Papers - ARAI Masakazu
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Maeda K., Fujisawa T., Arai M.
Journal of Materials Science: Materials in Electronics 36 ( 2 ) 2025.1
Publishing type：Research paper (scientific journal) Publisher：Journal of Materials Science: Materials in Electronics
Lattice-matched InAs/GaAs0.08Sb0.92 superlattices were grown on InAs substrates via metalorganic vapor-phase epitaxy, and the excitation intensity dependence of photoluminescence (PL) was measured from 20 to 300 K. The observed spectra were compared with the calculated spontaneous emission transitions. At 20 K, the changes in the calculated and measured spectral shapes with the carrier density in the wells closely concur. The blue shift of the emission peak, as the excitation intensity increased, was due to emission from a higher-order band. We determined the specific wavelengths at which the luminescence intensity increased rapidly at certain excitation intensities. These results broaden the spectral range. At 300 K, the PL spectrum was obtained only under strong excitation. Furthermore, higher-order transitions were also dominant in this case.
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GaAs基板上メタモルフィックInGaAs量子井戸レーザーの高温動作 Reviewed
荒井昌和
レーザー研究 52 ( 5 ) 253 2024.5
Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal)
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GaAsSb/InGaAs tunnel FETs using thick SiO<inf>2</inf> mask for regrowth Reviewed
Fan J., Xu R., Arai M., Miyamoto Y.
Japanese Journal of Applied Physics 63 ( 3 ) 03SP75 2024.3
Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Applied Physics
The regrowth conditions for lateral tunnel FETs featuring heterojunctions involve a tradeoff between selective growth and heavy doping. This study mitigated the connection between single crystals on the InP layer and polycrystals on the SiO2 mask by significantly increasing the thickness of the SiO2 mask to surpass that of the growing GaAsSb layer. We successfully fabricated p-GaAsSb/i-InGaAs tunnel FETs using a thick SiO2 mask, wherein the carrier concentration of the p-GaAsSb source was 5 × 1019 cm−3, and the growth temperature was maintained at 500 °C. The observed current-voltage (I-V) characteristics exhibited an on/off ratio of 5 × 104 and demonstrated ambipolar current behavior, confirming the presence of a p-type source. However, the observed subthreshold swing (SS) was limited to 120 mV dec−1. In comparison with the I-V characteristics of the planar transistor, degradation of SS can be explained by interface state, and the factor that characterizes the change of the drain current with the surface potential d Ψ s / d ( log 10 I D ) is estimated as 52 mV dec−1
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Hombu K., Hikita K., Fujisawa T., Maeda K., Arai M.
Physica Status Solidi (A) Applications and Materials Science 2024.2
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Physica Status Solidi (A) Applications and Materials Science
Midinfrared photonic devices are used as lasers and photodetectors in optical gas sensors and fiber-optic communications. Herein, the pair number dependence and strain compensation dependence of the InAsSb/InAsP superlattice structure to increase luminescence intensity and reduce crystal defects is investigated. InAs substrates are used to demonstrate various effects of strain compensation, including its role in increasing luminescence intensity and improving the surface flatness. Furthermore, the photoluminescence spectra of a grown superlattice between the InAs substrate and GaAs substrate with two-temperature-step growth are shown.
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Surface morphology improvement by diethylzinc doping on metamorphic InAs on GaAs using MOVPE Reviewed
Arai M., Nakagawa S., Hombu K., Hirata Y., Maeda K.
Journal of Crystal Growth 617 127274 2023.9
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Crystal Growth
We investigate the effect of diethylzinc doping on surface roughness during InAs growth on a GaAs substrate using metal-organic vapor phase epitaxy. Surface roughness was measured using atomic force microscopy and scanning electron microscopy. The surface flatness was considerably improved following the introduction of diethylzinc. Furthermore, we evaluate the Raman scattering and X-ray diffraction to investigate the crystallinity. The results confirm that diethylzinc doping effectively improves surface roughness.
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Crude Protein Content Estimation of Rhodes Grass Using Vegetation Indices Calculated by the Spectral Reflectance Reviewed
Arai Masakazu, Nakamura Keishiro, Ishigaki Genki
Japanese Journal of Grassland Science 69 ( 1 ) 23 - 26 2023.4
Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Grassland Science
DOI： 10.14941/grass.69.23
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Electrode Shape Dependence of InGaAsP Photovoltaic Characteristics under Laser Irradiation for Optical Wireless and Fiber Power Transmission Reviewed
Masakazu ARAI, Akira KUSHIYAMA, Yuga MOTOMURA, and Kensuke NISHIOKA
The Review of Laser Engineering 51 ( 3 ) 171 - 175 2023.3
Authorship：Lead author, Last author Language：English Publishing type：Research paper (scientific journal)
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Arai Masakazu, Ikari Tetsuo, Fukuyama Atsuhiko, Sakoda Riku, Yatabe Tatsuhiko
Memoirs of Faculty of Engineering, University of Miyazaki 51 63 - 67 2022.11
Language：Japanese Publishing type：Research paper (scientific journal)
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Maeda Koji, Arai Masakazu, Ohama Tomohito, Iwakiri Yuto, Fujisawa Takeshi
Memoirs of Faculty of Engineering, University of Miyazaki 51 35 - 39 2022.11
Language：Japanese Publishing type：Research paper (scientific journal)
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Wide Wavelength Range Emission from InAs/GaSb Type-II Superlattice Grown by MOVPE
Arai M., Iwakiri Y., Fujisawa T., Maeda K.
Conference Digest - IEEE International Semiconductor Laser Conference 2022-October 2022
Language：Japanese Publishing type：Research paper (international conference proceedings) Publisher：Conference Digest - IEEE International Semiconductor Laser Conference
We investigated the emission wavelength shift of type-II InAs/ GaSb superlattice on InAs substrate grown by MOVPE. With increasing the injection carrier density, very wide wavelength range emission over 2000 nm was observed. Calculated spectrum using k p perturbation method show the same tendency.
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LiDARとドローンを用いた牧草の収量推定 Reviewed
荒井昌和，庄中原，中村渓士郎，石垣元気，小川将克
レーザー研究 第49巻 ( 第10号 ) 2021.10
Language：Japanese Publishing type：Research paper (scientific journal)
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Ohishi Yuki, Imamura Yuki, Arai Masakazu, Maeda Koji, Oishi Yuki
Memoirs of Faculty of Engineering, University of Miyazaki 50 75 - 78 2021.9
Language：Japanese Publishing type：Research paper (scientific journal)
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Zn Doping Effect on Surface Morphology of Metamorphic InAs on GaAs Grown by MOVPE
Nakagawa S., Imamura Y., Hirata Y., Maeda K., Arai M.
26th Microoptics Conference, MOC 2021 2021
Language：Japanese Publishing type：Research paper (international conference proceedings) Publisher：26th Microoptics Conference, MOC 2021
We investigate the effect of Zn doping on surface roughness during InAs growth on GaAs substrate by metal organic vapor phase epitaxy (MOVPE). The surface roughness was measured by atomic force microscope (AFM) and scanning electron microscope (SEM). We confirmed the Zn doping was effective to improve the surface roughness.
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Sakakura M., Kita N., Ishigaki G., Arai M.
26th Microoptics Conference, MOC 2021 2021
Language：Japanese Publishing type：Research paper (international conference proceedings) Publisher：26th Microoptics Conference, MOC 2021
We investigated the correlation among the crude protein content of grass, the vegetation index and fluorescence intensity for non-destructive nutrient estimation in farm land. Vegetation index image was measured through optical band pass filter under sunlight. Fluorescence was measured under blue LED irradiation. We confirmed high correlation to crude protein content.
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Preface to Special Issue on Laser Applications to Agriculture and Agricultural Products Reviewed
The Review of Laser Engineering 49 ( 10 ) 548 2021
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Laser Society of Japan
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Aso Taiki, Ohishi Yuki, Imamura Yuki, Arai Masakazu, Maeda Koji
Memoirs of Faculty of Engineering, University of Miyazaki 49 69 - 72 2020.9
Language：Japanese Publishing type：Research paper (scientific journal)
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Tamura Hiroki, Morita Chihiro, Bonkobara Yasuhiro, Arai Masakazu, Sugamoto Kazuhiro, Sakamoto Makoto, Ishizu Takahiro, Morita Chihiro
Memoirs of Faculty of Engineering, University of Miyazaki 49 17 - 22 2020.9
Language：Japanese Publishing type：Research paper (scientific journal)
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Excitation Intensity Dependence of Photoluminesence on InAs/GaSb Superlattice with Constant Ratio of Layer Thickness
2020.2
Language：Japanese Publishing type：Research paper (bulletin of university, research institution)
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Temperature Dependence of Mid-infrared Photoluminescence for InAs/GaSb Superlattice with Varying GaSb Layer Thickness
2020.2
Language：Japanese Publishing type：Research paper (bulletin of university, research institution)
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Microscopic gain analysis of modulation-doped GeSn/SiGeSn quantum wells: epitaxial design toward high-temperature lasing Reviewed
T. Fujisawa, M. Arai, and K. Saitoh
Optics Express 27 ( 3 ) 2457 2019.4
Language：English Publishing type：Research paper (scientific journal)
DOI： 10.1364/OE.27.002457
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Akie M., Fujisawa T., Sato T., Arai M., Saitoh K.
IEEE Journal of Selected Topics in Quantum Electronics 24 ( 6 ) 2018.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Journal of Selected Topics in Quantum Electronics
© 2018 IEEE. We propose a taper coupler electroabsorption modulator (EAM) composed of GeSn/SiGeSn multiple-quantum-well (MQW) on Ge-on-Si platform for mid-infrared (2 μm) integrated optical active devices. The epitaxial design is performed by calculating the absorption spectra of GeSn/SiGeSn MQW using many-body theory to investigate the extinction characteristics of GeSn MQW waveguides. Two types of taper couplers are considered for connecting Ge-rib waveguide and GeSn-MQW-highmesa waveguide efficiently. One is an adiabatic taper coupler (ATC) type EAM and it is useful for thin Ge-buffer structure in terms of the extinction ratio. Another is a resonant taper coupler (RTC) type EAM and it is superior to ATC type EAM for thick Ge-buffer. It is confirmed that RTC type EAM can obtain the high extinction characteristics with low-loss and shorter device length (6.87 dB, -3.97 dB, and 215 μm) compared with conventional ATC type EAM for thick Ge-buffer (5.67 dB, -4.9 dB, and 340 μm).
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Arai M., Takahashi K., Yamagata Y., Inoue Y., Wakaki R., Maeda K.
Japanese Journal of Applied Physics 57 ( 8 ) 2018.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Applied Physics
© 2018 The Japan Society of Applied Physics. We investigated the gas flow sequence to realize a short-period and lattice-matched InAs/GaAsSb superlattice on an InAs substrate by metalorganic vapor phase epitaxy (MOVPE) growth for applications in mid-infrared photonic devices. The arsenic composition of GaAsSb for lattice matching was adjusted by adding AsH3flow to residual arsenic incorporation. The growth conditions for lattice-matched superlattices at a period of 5 nm were found. The superlattices with period thicknesses of 1 to 9 nm were successfully confirmed by the photoluminescence (PL) peak in the range from 2.4 to 5 µm depending on layer thickness at 20 K. The emission wavelength can be controlled by changing the layer thickness of superlattices. The results led to the improvement of InAs/GaAsSb type II superlattice growth.
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Heteroepitaxial Growth of GaAs/Ge Buffer Layer on Si for Metamorphic InGaAs Lasers Invited Reviewed
M. Arai, T. Kakitsuka and S. Matsuo
IEICE TRANSACTIONS on Electronics E101.C ( 7 ) 537 - 544 2018.7
Language：English Publishing type：Research paper (scientific journal)
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中赤外発光受光素子用III-V(Sb)系材料の結晶成長と評価 Reviewed
荒井昌和,高橋翔,井上祐貴,藤原由生,吉元圭太,山形勇也,西岡賢祐,前田幸治
レーザー研究 2017.12
Language：Japanese Publishing type：Research paper (scientific journal)
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MOVPE Growth of Lattice Matched InAs/GaAsSb Superlattice on InAs Substrate for Mid-Infrared Sensing Devices Reviewed
Kakeru Takahashi, Yuki Fujiwara, Yuya Yamagata,Keita Yoshimoto, Yuki Inoue, Ryosuke Wakaki, Koji Maeda, Masakazu Arai
22nd Microoptics Conference 2017.11
Language：English Publishing type：Research paper (international conference proceedings)
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Sato T., Akie M., Arai M., Fujisawa T., Saitoh K.
2017 Conference on Lasers and Electro-Optics, CLEO 2017 - Proceedings 2017-January 1 - 2 2017.10
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：2017 Conference on Lasers and Electro-Optics, CLEO 2017 - Proceedings
© 2017 IEEE. A highly efficient GeSn electroabsorption modulator using higher-order-mode is proposed for mid-infrared photonics. Proposed structure is suitable for monolithic integration on Ge-on-Si platform and > 10 dB enhancement of the extinction ratio is possible.
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Design and Growth of Metamorphic Sb-based materials on GaAs substrate for Mid-Infrared Photonic Devices Reviewed
Keita Yoshimoto, Yuya Yamagata,Yuga Imamura and Masakazu Arai
2017 CLEO Pacific Rim Conference 2017.7
Language：English Publishing type：Research paper (international conference proceedings)
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Wavelength Range Extension by Chirped and Nitrogen Incorporated InGaAs(N) Quantum Wells for Super Luminescent Diode Reviewed
Yuga Imamura, Keita Yoshimoto, Masakazu Arai
2017 CLEO Pacific Rim Conference 2017.7
Language：English Publishing type：Research paper (international conference proceedings)
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松島 敏則, 三成 剛生, 木下 啓藏, 杉山 睦, 櫻井 啓一郎, 手老 龍吾, 荒井 昌和, 木村 康男, 佐藤 勝昭, 内山 裕士
応用物理 86 ( 10 ) 854 - 857 2017
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：公益社団法人 応用物理学会
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Epitaxial growth on lattice-mismatched substrate for high-performance lasers
Nakao R., Arai M., Kobayashi W., Kakitsuka T., Yamamoto T., Matsuo S.
2016 Compound Semiconductor Week, CSW 2016 - Includes 28th International Conference on Indium Phosphide and Related Materials, IPRM and 43rd International Symposium on Compound Semiconductors, ISCS 2016 2016.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：2016 Compound Semiconductor Week, CSW 2016 - Includes 28th International Conference on Indium Phosphide and Related Materials, IPRM and 43rd International Symposium on Compound Semiconductors, ISCS 2016
© 2016 IEEE. Heteroepitaxial, or metamorphic, growth enables us to overcome limitations on the performance of semiconductor devices caused by the lattice-matching restriction. We have demonstrated high-crystalline-quality metamorphic grown InGaAs and GaAs/Ge layers on GaAs and Si substrates, respectively. The InGaAs layer on GaAs allows us to make laser diodes operating at 25 Gbit/s with high characteristic temperature of 187 K at 1.3-μm wavelength. Moreover, III-V compound semiconductors on Si substrate are promising to for large-scale and low-cost fabrication. We have also achieved a high-crystalline-quality GaAs layer on Si substrate by using an MOVPE-grown Ge buffer layer.
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Nakao R., Arai M., Kobayashi W., Yamamoto T., Matsuo S.
IEEE Journal on Selected Topics in Quantum Electronics 21 ( 6 ) 2015.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Journal on Selected Topics in Quantum Electronics
© 1995-2012 IEEE. We demonstrate a lattice relaxation control by in situ curvature measurement for a metamorphic buffer. Using this relaxation control, we investigated a thin (240 nm) 0.15 Ga 0.85 As metamorphic buffer for fabricating an unstrained In 0.10 Ga 0.90 As quasi-substrate on a GaAs substrate and succeeded in fabricating a 1.3-μm metamorphic InGaAs multiple-quantum well laser diode (LD) on the metamorphic buffer. We confirmed that the LD was directly modulated at 25 Gb/s with a high-characteristic temperature (T0 = 187 K).
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Kobayashi W., Arai M., Fujisawa T., Sato T., Ito T., Hasebe K., Kanazawa S., Ueda Y., Yamanaka T., Sanjoh H.
Optics Express 23 ( 7 ) 9533 - 9542 2015.4
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Optics Express
©2015 Optical Society of America. We propose a novel approach for simultaneously controlling the chirp and increasing the output power of an EADFB laser by monolithically integrating a short-cavity SOA. We achieved a 40-Gbit/s 5-km SMF transmission at a wavelength of 1.55 μm by using an EADFB SOA with a lower power consumption than a stand-alone EADFB laser.
DOI： 10.1364/OE.23.009533
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25-Gb/s operation of metamorphic laser with thin metamorphic buffer on GaAs substrate
Nakao R., Arai M., Kobayashi W., Kohtoku M.
Conference Digest - IEEE International Semiconductor Laser Conference 68 - 69 2014.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Digest - IEEE International Semiconductor Laser Conference
© 2014 IEEE. We have achieved the first 25-Gb/s operation for a metamorphic laser with a high characteristic temperature (T0=187 K) at 1.3 μm on a GaAs substrate using a thin metamorphic buffer to suppress wafer curvature.
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Kobayashi W., Arai M., Fujisawa T., Shibata Y., Sato T., Ito T., Hasebe K., Yamanaka T., Sanjoh H.
European Conference on Optical Communication, ECOC 2014.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：European Conference on Optical Communication, ECOC
© 2014 Systematic Paris Region Systems and ICT Cluster. We demonstrate 40-Gbit/s operation by chirp control and increased output power employing an EADFB laser integrated with short-cavity SOA. We achieved 5-km SMF transmission in the 1.55-μm wavelength with lower power consumption than a stand-alone EADFB.
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Planar n-SI-n heterostructure athermal InP (110) optical modulator
Ogiso Y., Nakanishi Y., Kanazawa S., Yamada E., Tanobe H., Arai M., Shibata Y., Kohtoku M.
Optics Express 22 ( 21 ) 25776 - 25781 2014.10
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Optics Express
© 2014 Optical Society of America. We report an athermal InP (110) optical modulator with a simple planar n-SI-n heterostructure. A symmetrical push-pull operation provides a high-extinction ratio of >25 dB over the entire C-band and zero-chirp modulation. A Mach-Zehnder optical modulator (MZM) exhibits a 3 dBEO bandwidth of 30 GHz and 40-Gb/s NRZ high-speed modulation with wavelength and temperature insensitive operation. We also successfully demonstrate an MZM integrated twin-IQ modulator that exhibits 56-Gb/s × 2 athermal QPSK modulation at constant drive and bias voltages.
DOI： 10.1364/OE.22.025776
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Novel planar structure single-RF drive MZ optical modulator on InP(110) substrate
Ogiso Y., Arai M., Yamada E., Tanobe H., Shibata Y., Kohtoku M.
Conference Proceedings - International Conference on Indium Phosphide and Related Materials 2013.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Proceedings - International Conference on Indium Phosphide and Related Materials
A MZ optical modulator (MZM) with a novel planar structure was proposed. A single-RF drive push-pull MZM with a simple coplanar waveguide (CPW) was fabricated by utilizing a (110)-oriented InP substrate in terms of the crystallographic orientation dependence of the electro-optic Pockels effect. The device exhibits a 3 dB-EO bandwidth of 30 GHz and 40 Gb/s NRZ high speed modulation. © 2013 IEEE.
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Static properties of planar Mach-Zehnder optical modulator on (110) InP substrate
Ogiso Y., Arai M., Sato T., Shibata Y., Kohtoku M.
Electronics Letters 49 ( 14 ) 901 - 903 2013.7
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Electronics Letters
A single drive Mach-Zehnder optical modulator with a new simple planar structure was investigated by utilising a lateral electric field. To obtain the Pockels effect induced by the lateral electric field, a (110)-oriented InP substrate is introduced. The device exhibits an extinction ratio of > 25 dB over the entire C-band, a wide operating wavelength bandwidth of 80 nm and temperature insensitivity. © 2013 Institution of Engineering and Technology.
DOI： 10.1049/el.2013.1659
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Arai M., Kobayashi W., Kohtoku M.
IEEE Journal on Selected Topics in Quantum Electronics 19 ( 4 ) 2013.5
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Journal on Selected Topics in Quantum Electronics
We demonstrated a 1.3-μm-range laser with a high characteristic temperature (T0 = 220 K) and the highest operating temperature (200 °C) ever reported for a metamorphic laser. The temperature characteristics were greatly improved by inserting a p-InGaAlAs electron stopper layer. In addition, we realized a high fr value with a low injection current using a short cavity (L = 200 μm) laser operating at a high temperature. The bias current at 10 Gbit/s and 85 °C was only 15 mA. These results show that a laser with a metamorphic buffer on a GaAs substrate is a good candidate as an uncooled light source with low power consumption. © 1995-2012 IEEE.
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1.3-μm-range InGaAs metamorphic laser for low power consumption operation
Arai M., Kobayashi W., Kohtoku M.
Conference Digest - IEEE International Semiconductor Laser Conference 60 - 61 2012.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Digest - IEEE International Semiconductor Laser Conference
We demonstrated a 1.3-μm-range metamorphic short cavity laser with a high characteristic temperature (T0=200K). The bias current for 10-Gbps modulation at high temperature was reduced and we revealed the potential for low-power consumption operation. © 2012 IEEE.
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Demonstration of high temperature operation in 1.3-μm-range metamorphic InGaAs laser
Arai M., Kondo Y., Kanazawa S., Tadokoro T., Kohtoku M.
2012 Conference on Lasers and Electro-Optics, CLEO 2012 2012.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：2012 Conference on Lasers and Electro-Optics, CLEO 2012
A 1.3-μm-range metamorphic InGaAs laser with high characteristic temperature (T 0 = 220 K) and the highest operating temperature (200°C) ever reported for a metamorphic laser has been achieved by inserting an electron stopper layer in the p-cladding layer. © 2012 OSA.
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InGaAs metamorphic laser for low-power-consumption operation
Arai M., Kobayashi W., Kohtoku M.
NTT Technical Review 10 ( 12 ) 2012.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：NTT Technical Review
In this article, we review our efforts to reduce the power consumption of optical transmitter modules for Ethernet and telecommunications use. To reduce the power consumption, we aim to eliminate the light source's temperature controller and improve the stability of the output power and modulation characteristics under ambient temperature conditions. We describe a 1.3-μm-range metamorphic laser on a GaAs substrate that exhibits improved temperature characteristics. It has a characteristic temperature of 220 K and is capable of lasing up to 200°C. In addition, the bias current for 10-Gbit/s modulation at high temperature has been reduced. This laser is promising for uncooled light sources operating with low power consumption.
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Fujisawa T., Yamanaka T., Tadokoro T., Fujiwara N., Arai M., Kobayashi W., Kawaguchi Y., Tsuzuki K., Kano F.
IEEE Journal of Quantum Electronics 47 ( 1 ) 60 - 65 2011
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Journal of Quantum Electronics
We have found that the extinction ratio (ER) of an electroabsorption modulator integrated with a distributed feedback laser strongly depends on the incident power to the modulator. Our theoretical consideration based on full device simulation reveals that the temperature change in the modulator dominates the phenomenon. To obtain the intrinsic extinction characteristics of the modulator, we use microscopic theory, which takes into account quantum mechanical many-body interactions in semiconductors and makes it possible to exclude unknown experimental fitting parameters. A heat-flux analysis is performed for the calculation of the temperature distribution in the entire device. As the incident power to the modulator increases, the photocurrent also increases, leading to an increase in the temperature of the modulator by some tens of degrees Celsius by Joule heating. The increase red-shifts the absorption spectrum of the modulator, and the detuning, which is the difference between the lasing wavelength and the band-edge wavelength of the modulator, becomes small, leading to a larger ER. The calculated results are in good agreement with the experiment, showing the validity of our discussion, and indicate that the ER of electroabsorption modulators is strongly affected by the internal heating of the device. © 2010 IEEE.
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Kobayashi W., Arai M., Fujiwara N., Fujisawa T., Tadokoro T., Tsuzuki K., Yamanaka T., Kano F.
Technical Digest - 15th OptoElectronics and Communications Conference, OECC2010 840 - 841 2010.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Technical Digest - 15th OptoElectronics and Communications Conference, OECC2010
10-Gb/s 80-km and 40-Gb/s 2-km SMF transmissions with low power penalty over wide temperature range are demonstrated with a 1.55-μm InGaAlAs EAM-integrated DFB laser. These devices are suitable for use as 10-/40-Gb/s uncooled light sources.
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Full C-band 10-Gb/s 40-km SMF transmission of InGaAlAs electroabsorption modulator
Kobayashi W., Fujiwara N., Yamanaka T., Tadokoro T., Fujisawa T., Shibata Y., Ishikawa M., Arai M., Tsuzuki K., Kano F.
Journal of Lightwave Technology 28 ( 20 ) 3012 - 3018 2010.10
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Lightwave Technology
This paper describes the 10-Gb/s, full C-band (1530 to 1565 nm) operation of 1.55-μm electroabsorption modulators (EAMs) designed to eliminate the cost of a back up light source for a 10-Gb/s dense wavelength division multiplexing (DWDM) system. We employ InGaAlAs as the material for the EAM multiple-quantum well (MQW), and design it to achieve a sufficient extinction ratio and a low chirp (α) parameter over a wide wavelength range. A ridge waveguide buried in benzocyclobutene (BCB) is also introduced for the EAM waveguide. We design the width of the ridge waveguide and the thickness of a core layer that includes an MQW and separate confinement hetero-structure (SCH) layers by calculating the EAM capacitance. 6-well and 12-well based EAMs are fabricated to allow us to compare the wavelength dependence of their static/dynamic extinction ratios (SER/DER), and their small-signal electrical to optical (E/O) responses. We confirm that the 12-well based EAM provides a sufficient DER over the C band. We also determine that the wavelength detuning (Δλ) between an input light wavelength and an EA absorption peak is 100 nm at an input wavelength of 1530 nm, and evaluate the wavelength dependence of the chirp parameter, and the 40-km SMF transmission characteristics such as eye diagrams and the power penalty (PP). These experiments were conducted using a wavelength tunable laser while maintaining the input power of the EAM at about 13 dBm and changing the input wavelength over the C band. The EAM was also driven with a constant modulation voltage swing (VPP)of 2.0 V while changing only the EAM bias voltage (Vb). We also measured the input power dependence of the chirp parameter. These results show that the 12-well based InGaAlAs EAM is a promising candidate for an optical modulator that can be used over the C band in a low cost 10-Gb/s optical network system. © 2010 IEEE.
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Fujisawa T., Yamanaka T., Tadokoro T., Fujiwara N., Arai M., Kobayashi W., Kawaguchi Y., Tsuzuki K., Kano F.
Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference: 2010 Laser Science to Photonic Applications, CLEO/QELS 2010 2010.10
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference: 2010 Laser Science to Photonic Applications, CLEO/QELS 2010
Incident-power-dependent extinction ratio of electroabsorption modulators is shown and theoretically investigated by using microscopic theory combined with heat-flux calculation. The phenomenon stems from voltage-dependent temperature rise and the calculated results agree well with the experiment. © 2010 Optical Society of America.
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Growth of large platy InGaAs crystals and fabrication of semiconductor laser diodes
Kinoshita K., Yoda S., Arai M., Kawaguchi Y., Kondo Y., Kano F., Aoki H., Hosokawa T., Yamamoto S., Matsushima M.
Conference Proceedings - International Conference on Indium Phosphide and Related Materials 74 - 76 2010.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Proceedings - International Conference on Indium Phosphide and Related Materials
We have succeeded in increasing size of InxGa 1-x As (x: 0.1 - 0.13) platy single crystals to 30 x30 mm 2 in surface area for mass production of laser diodes. Key points are to suppress convection in a melt and to keep constant temperature gradient for obtaining homogeneous crystals. Grown crystals have enough quality as substrates for 1.3 μm laser diodes. Fabricated laser diodes on these substrates were evaluated by measuring lasing characteristics at various temperatures and by measuring bit error rate for transmission through a single mode fiber up to 20 km. Lasers showed high temperature stability and error free transmission and showed the merit of ternary substrates.
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Fujisawa T., Arai M., Kano F.
Journal of Applied Physics 107 ( 9 ) 2010.5
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Applied Physics
Electroabsorption in highly strained GaInAs and GaInNAs quantum wells (QWs) grown on GaInAs or quasi-GaInAs substrates is investigated by using microscopic many-body theory. The effects of various parameters, such as strain, barrier height, substrate composition, and temperature are thoroughly examined. It is shown that the value of the absorption coefficient strongly depends on the depth of the QWs under large bias electric field due to the small overlap integral of wave functions between the conduction and valence bands. The use of GaInNAs QWs makes the strain in the well layer very small. Further, the effective quantum-well depth is increased in GaInNAs QWs due to the anticrossing interaction between the conduction and N-resonant bands, making it possible to obtain larger absorption coefficient under large bias electric fields without using wide-band gap materials for barriers. © 2010 American Institute of Physics.
DOI： 10.1063/1.3360937
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Kobayashi W., Arai M., Yamanaka T., Fujiwara N., Fujisawa T., Tadokoro T., Tsuzuki K., Kondo Y., Kano F.
Journal of Lightwave Technology 28 ( 1 ) 164 - 171 2010.1
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Lightwave Technology
This paper describes the wide temperature range operation of an electroabsorption modulator (EAM) integrated with DFB laser diodes (LDs) (EML) designed to reduce the power consumption and size of optical transmitters.We optimized the multiquantum wells (MQWs) for LD and EAM separately to realize uncooled operation. We employed a conduction band offset (ΔE c ) of around 250 meV for the LD and 150 meV for the EAM. The number of well layers was set at 6 for the LD and 12 for the EAM, respectively.We fabricated theEMLusing a butt-joint (BJ) process to allow us to design the LD and the EAM independently. We introduced a ridge waveguide structure for the LD and EAM waveguides, and designed the width of the LD and EAM mesa to achieve a high optical coupling efficiency between the LD and the EAM. We then used the 200- m-long EAM for 10-Gb/s operation and the 150-μm-long EAM for 40-Gb/s operation, and thus obtained a dynamic extinction ratio of over 9 dB at 10 Gb/s from -25 °C to 100 C and of 8.2 dB at 40 Gb/s from -15 to 80°C. We achieved a power penalty of less than 2 dB after an 80-km single-mode fiber (SMF) transmission at 10 Gb/s and a 2-km SMF transmission at 40 Gb/s over a wide temperature range. These results confirm the suitability of this EML with a BJ structure for use as a 10-Gb/s or 40-Gb/s uncooled light source. © 2009 IEEE.
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Fujisawa T., Arai M., Fujiwara N., Kobayashi W., Tadokoro T., Tsuzuki K., Akage Y., Iga R., Yamanaka T., Kano F.
European Conference on Optical Communication, ECOC 2009.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：European Conference on Optical Communication, ECOC
High-performance 1.3-μm InGaAlAs electroabsorption modulator integrated with DFB laser module for metro-area 100-Gbi/s Ethernet system (100GBASE-ER4) has been realized. Long-reach (40 km) error-free transmission under 25-Gbit/s operation on SMF is achieved for the first time. © VDE VERLAG GMBH.
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Kobayashi W., Arai M., Yamanaka T., Fujiwara N., Fujisawa T., Ishikawa M., Tsuzuki K., Shibata Y., Kondo Y., Kano F.
IEEE Photonics Technology Letters 21 ( 15 ) 1054 - 1056 2009.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Photonics Technology Letters
We have developed a 1.55-μm uncooled electroabsorption modulator (EAM) integrated distributed-feedback laser with an InGaAlAs multiple quantum-well active/absorption stripe. These two components were directly butt-jointed using a simplified fabrication process. We demonstrated an 80-km single-mode fiber (SMF) transmission at 10 Gb/s over an extremely wide temperature range of 125°C (25°C-100°C) by adjusting only the bias voltage of the EAM depending on the temperature while keeping the modulation voltage swing constant at 2.5 V. We achieved a dynamic extinction ratio of over 9 dB and an 80-km SMF transmission with a power penalty of less than 2 dB over a wide temperature range. © 2009 IEEE.
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Kobayashi W., Yamanaka T., Arai M., Fujiwara N., Fujisawa T., Tsuzuki K., Ito T., Kondo Y., Kano F.
Conference Proceedings - International Conference on Indium Phosphide and Related Materials 367 - 370 2009.10
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Proceedings - International Conference on Indium Phosphide and Related Materials
A 2-km 40-Gb/s transmission from -15 to 80°C is demonstrated using a 1.55-μm InGaAlAs EML for the first time. A powerpenalty below 2 dB with a dynamic extinction ratio of over 8.2 dB is achieved at -15°C.
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Uncooled (25-85 °c) 10-GbPs operation of 1.3-μm-range metamorphic InGaAs laser on gaas substrate
Arai M., Tadokoro T., Kobayashi W., Fujisawa T., Nakashima K., Yuda M., Kondo Y.
Conference Proceedings - International Conference on Indium Phosphide and Related Materials 226 - 229 2009.10
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Proceedings - International Conference on Indium Phosphide and Related Materials
We have realized the first 10-Gbps direct modulation of a 1.3-μm-range laser diode with an InGaAs metamorphic buffer on a GaAs substrate. A 200-μm-long device had threshold currents as low as 5.2 and 11.4 mA at 25 and 85 °C, respectively. The maximum operating temperature was 135 °C. This excellent performance is attributed to the high quality InGaAs metamorphic buffer. ©2009 IEEE.
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Arai M., Tadokoro T., Fujisawa T., Kobayashi W., Nakashima K.
IEEE Photonics Technology Letters 21 ( 18 ) 1344 - 1346 2009.9
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Photonics Technology Letters
We have realized 10-Gb/s direct modulation up to 100 C using a metamorphic InGaAs multiple-qunatum well (MQW) laser on a GaAs substrate. The highly strained InGaAs quantum well (QW) and strain-compensated GaAs barrier layer allowed 1.3-μ m-range lasing and an increased number of QWs (six). This laser with a 200-μm-long short cavity and a narrow ridge had maximum relaxation oscillation frequencies of 13 and 6 GHz at 25° C and 100 °C, respectively. A 10-km single-mode fiber error-free transmission was successfully obtained at a temperature of 85 ° C. © 2009 IEEE.
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Kobayashi W., Yamanaka T., Arai M., Fujiwara N., Fujisawa T., Tsuzuki K., Ito T., Tadokoro T., Kano F.
IEEE Photonics Technology Letters 21 ( 18 ) 1317 - 1319 2009.9
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Photonics Technology Letters
We present the uncooled operation of a 1.55-μm 40-Gb/s InGaAlAs electroabsorption modulator (EAM) integrated distributed-feedback (DFB) laser within a temperature range of 95 °C (-15 ° C to 80 °C). To the best of our knowledge, this is the largest temperature range reported so far for such a 40-Gb/s EAM integrated DFB laser. We designed the EAM to operate at high speed by reducing the electrical parasitics, and we achieved a 3-dB frequency bandwidth of over 39 GHz for an EAM length of less than 150 m. We demonstrated a 2-km single-mode fiber (SMF) transmission at 40-Gb/s over a wide temperature range of 15 °C to 80 °C by adjusting only the bias voltage to the EAM while keeping the modulation voltage swing constant at 2.0 V when the temperature changed. We achieved a dynamic extinction ratio of over 8.2 dB and a 2-km SMF transmission with a power penalty of less than 2 dB over a wide temperature range. © 2009 IEEE.
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Fujisawa T., Arai M., Yamanaka T., Kondo Y., Kano F.
Journal of Applied Physics 105 ( 11 ) 2009.7
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Applied Physics
Material properties of highly strained GaInNAs quantum wells grown on GaInAs or quasi-GaInAs substrates are investigated by using microscopic theory together with a band structure calculation based on ten-band kp theory specially formulated for highly strained materials. It is shown that the material gain of GaInNAs quantum wells is reduced by incorporating N into a well layer although the strain in the well layer becomes small. The reduction can be compensated by properly choosing barrier materials. The performance of laser diodes, such as characteristic temperatures T 0 and differential gains, is also investigated, and the present results show that very high T 0 (≃140 K) and differential gain with moderate strain (≃1.6%) can be achieved by carefully designing quantum well structures, indicating the applicability of these lasers for high-temperature and high-speed operation. © 2009 American Institute of Physics.
DOI： 10.1063/1.3126522
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Arai M., Nakashima K., Fujisawa T., Tadokoro T., Kobayashi W., Yuda M., Kondo Y.
IEEE Journal on Selected Topics in Quantum Electronics 15 ( 3 ) 724 - 730 2009.5
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Journal on Selected Topics in Quantum Electronics
In this paper, we have newly developed an InGaAs metamorphic buffer on a GaAs substrate grown by metalorganic vapor-phase epitaxy, and realized a fully relaxed quasi-InGaAs substrate with low threading dislocation density. We have also successfully developed a 1.3-μ m-range ridge waveguide laser with InGaP upper cladding and InAlGaAs lower cladding layers. This laser has achieved the highest continuous-wave operating temperature (173° C) reported for a metamorphic laser. We measured the relaxation oscillation frequency from the relative intensity noise and undertook a 10-Gb/s direct modulation experiment. © 2006 IEEE.
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Arai M., Tadokoro T., Fujisawa T., Kobayashi W., Nakashima K., Yuda M., Kondo Y.
Electronics Letters 45 ( 7 ) 359 - 360 2009.4
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Electronics Letters
The first direct modulation of a 1.3m-range metamorphic laser diode on a GaAs substrate has been realised. A 200m-long device had threshold currents as low as 5.2 and 11.4mA at 25 and 85°C, respectively. This laser also achieved 10Gbit/s direct modulation up to 85°C. © 2009 The Institution of Engineering and Technology.
DOI： 10.1049/el.2009.0263
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10-Gbps direct modulation using a 1.31-μm ridge waveguide laser on an InGaAs ternary substrate
Arai M., Kobayashi W., Fujisawa T., Yuda M., Tadokoro T., Kinoshita K., Yoda S., Kondo Y.
Applied Physics Express 2 ( 2 ) 2009.2
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Applied Physics Express
We have realized a high-performance ridge waveguide laser diode on an InGaAs ternary substrate. To improve the thermal conductivity, we chose a low indium content (In: 0.13) InGaAs substrate and realized a 1.31-μm emission using highly strained InGaAs multiple-quantum-wells. The improved thermal conductivity of the substrate enables continuous wave operation even with a reduced ridge width and a short cavity length (L = 200 μm). These improvements led to the first demonstration of a 10-Gbps data transmission using a laser on an InGaAs ternary substrate. © 2009 The Japan Society of Applied Physics.
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Kobayashi W., Arai M., Yamanaka T., Fujiwara N., Fujisawa T., Ishikawa M., Tsuzuki K., Shibata Y., Kondo Y., Kano F.
Conference on Optical Fiber Communication, Technical Digest Series 2009
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference on Optical Fiber Communication, Technical Digest Series
An 80-km SMF transmission at 10-Gb/s using a 1.55-μm, InGaAlAs EML was demonstrated over an extended temperature range (-25°C to 100°C). A dynamic extinction ratio of over 9 dB at -25°C was obtained. © 2009 OSA.
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Kikuchi N., Shibata Y., Tsuzuki K., Yasui T., Ishikawa M., Ishii H., Arai M., Sato T., Kawaguchi Y., Kano F.
Conference on Optical Fiber Communication, Technical Digest Series 2009
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference on Optical Fiber Communication, Technical Digest Series
A traveling-wave-electrode InP n-p-i-n Mach-Zehnder modulator monolithically integrated with a semiconductor optical amplifier was developed. Loss-less operation and full C-band 40-Gbit/s DPSK modulation with a low driving voltage of 3 Vpp was successfully demonstrated. © 2009 OSA.
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Yasui T., Shibata Y., Kikuchi N., Tsuzuki K., Kawaguchi Y., Arai M., Yasaka H.
Conference Proceedings - International Conference on Indium Phosphide and Related Materials 2008.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Proceedings - International Conference on Indium Phosphide and Related Materials
10-Gbit/s optical duobinary transmission over a 200-km single-mode fiber is demonstrated using a lossless InP n-p-i-n MachZehnder modulator monolithically integrated with a semiconductor optical amplifier. The device gain exceeds 8 dB and the static extinction ratio is over 26 dB for a wavelength of 1550 nm. An error free operation was achieved with a power penalty of less than 5 dB at a low driving voltage of 2.8 Vpp for push-pull operation.
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Arai M., Fujisawa T., Kobayashi W., Nakashima K., Yuda M., Kondo Y.
Conference Digest - IEEE International Semiconductor Laser Conference 57 - 58 2008.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Digest - IEEE International Semiconductor Laser Conference
We have successfully developed a 1.26 μm ridge waveguide laser diode with an InGaAs metamorphic buffer on an GaAs substrate grown by metal-organic vapor-phase epitaxy. This laser has achieved the highest operating temperature (188 °C) reported for a metamorphic laser. ©2008 IEEE.
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Kinoshita K., Ueda T., Yoda S., Arai M., Kawaguchi Y., Kondo Y., Aoki H., Hosokawa T., Yamamoto S., Matsushima M.
Conference Proceedings - International Conference on Indium Phosphide and Related Materials 2008.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Proceedings - International Conference on Indium Phosphide and Related Materials
We have prepared homogeneous ternary In x Ga 1-x As (x: 0.1 - 0.13μm platy single crystals for 1.3 μm laser diode substrates by a novel bulk crystal growth technique named the TLZ (traveling liquidus-zone) method. We further improved the crystal quality by optimizing growth conditions and In x Ga 1-x As (x: 0.1 - 0.13) single crystals having high quality area larger than 10 ×30mm 2 were reproducibly grown.
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A 1.31 μm ridge waveguide laser for 10 Gbps direct modulation on an InGaAs ternary substrate
Arai M., Fujisawa T., Kobayashi W., Kawaguchi Y., Yuda M., Tadokoro T., Kondo Y., Kinoshita K., Ueda T., Yoda S.
Conference Proceedings - International Conference on Indium Phosphide and Related Materials 2008.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Proceedings - International Conference on Indium Phosphide and Related Materials
We have developed high performance ridge waveguide laser diodes on an InGaAs ternary substrate grown by a novel bulk crystal growth technique (TLZ method). A low indium content (In: 0.13) InGaAs substrate improves the thermal conductivity and enables laser operation even with a short cavity (L=200 μm). Single lateral mode operation was obtained by reducing the ridge width. This laser operates at a long wavelength of 1.31 μm with a highly strained InGaAs quantum well. These improvements led to the first demonstration of a 10 Gbps data transmission using a ridge waveguide laser on an InGaAs substrate.
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Arai M., Fujisawa T., Kobayashi W., Nakashima K., Yuda M., Kondo Y.
Electronics Letters 44 ( 23 ) 1359 - 1360 2008.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Electronics Letters
A 1.26m ridge waveguide laser diode with an InGaAs metamorphic buffer on a GaAs substrate grown by metal-organic vapour-phase epitaxy has been successfully developed. This laser has achieved the highest operating temperature (173°C) for continuous-wave operation reported for a metamorphic laser. © 2008 The Institution of Engineering and Technology.
DOI： 10.1049/el:20082657
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Yasui T., Shibata Y., Tsuzuki K., Kikuchi N., Kawaguchi Y., Arai M., Yasaka H.
OFC/NFOEC 2008 - 2008 Conference on Optical Fiber Communication/National Fiber Optic Engineers Conference 2008.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：OFC/NFOEC 2008 - 2008 Conference on Optical Fiber Communication/National Fiber Optic Engineers Conference
Full C-band 10-Gbit/s 100-km SMF transmission of NRZ signals is demonstrated using a lossless InP n-p-i-n Mach-Zehnder modulator monolithically integrated with a semiconductor optical amplifier. A power penalty of less than 1.5 dB is confirmed. © 2006 Optical Society of America.
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Yasui T., Shibata Y., Tsuzuki K., Kikuchi N., Ishikawa M., Kawaguchi Y., Arai M., Yasaka H.
IEEE Photonics Technology Letters 20 ( 13 ) 1178 - 1180 2008.7
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Photonics Technology Letters
An InP n-p-i-n Mach-Zehnder modulator and a semiconductor optical amplifier were monolithically integrated to compensate for the modulator's insertion loss. The device gain exceeded 10 dB, and fiber-to-fiber lossless operation was demonstrated for the full C-band region. The error-free transmission of a 10-Gb/s nonreturn-to-zero signal over a 100-km single-mode fiber was also demonstrated across the full C-band region. A power penalty of less than 1.5 dB was confirmed. © 2008 IEEE.
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Fujisawa T., Arai M., Kakitsuka T., Yamanaka T., Kondo Y., Yasaka H.
Applied Physics Express 1 ( 4 ) 0412031 - 0412033 2008.4
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Applied Physics Express
Temperature characteristics of multi-quantum-well lasers on InGaAs ternary substrates are investigated. By using InAlGaAs barriers and low-In-content InGaAs substrates, the characteristic temperature of the laser can reach as high as 150K between 25 and 85°C due to the enhancement of the material gain. Calculated characteristic temperatures are in good agreement with those obtained by experiment, showing the validity of the results presented here. © 2008 The Japan Society of Applied Physics.
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1.3 μm band InGaAs MQWs with InGaP metamorphic graded buffer layer on GaAs substrate
Arai M., Kondo Y.
Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest 2007.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest
We have realized 1.3 μm-band highly strained InGaAs multiple quantum wells on a metamorphic InGaP graded buffer layer on a GaAs substrate grown by metal-organic vapor-phase epitaxy. We confirmed that the InGaP metamorphic buffer is more effective in improving the crystal quality than InGaAs buffer by performing photoluminescence and transmission electron microscope measurements.
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GROWTH of platy InGaAs single crystals and fabrication of 1.3 μm laser diodes
Kinoshita K., Ueda T., Adachi S., Masaki T., Yoda S., Arai M., Watanabe T., Yuda M., Kondo Y.
Conference Proceedings - International Conference on Indium Phosphide and Related Materials 339 - 342 2007.10
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Proceedings - International Conference on Indium Phosphide and Related Materials
High quality In x Ga 1-x As platy single crystals (x: 0.1 - 0.2) were grown by the newly invented growth method named as the traveling liquidus-zone (TLZ) method. Laser diodes lasing at 1.3 μm wavelength were fabricated on these substrates and showed good temperature stability of output power as predicted. © 2007 IEEE.
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Arai M., Kinoshita K., Yoda S., Kondo Y.
Conference Proceedings - International Conference on Indium Phosphide and Related Materials 241 - 244 2007.10
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Proceedings - International Conference on Indium Phosphide and Related Materials
We have developed highly strained InGaAs quantum wells (QWs) with a 1.3 μm-band emission on a low indium content InGaAs ternary substrate using low temperature metal-organic vapor phase epitaxy (MOVPE). The indium content of the substrate is 0.1, and this has the advantage of providing good thermal conductivity and good crystal quality. In this study, we newly introduced a binary GaAs barrier layer for strain compensation. We performed photoluminescence (PL) and transmission electron microscope (TEM) measurements to confirm that the crystal quality had improved. We realized a broad area laser with GaAs strain compensation that achieved low threshold current operation. © 2007 IEEE.
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Arai M., Watanabe T., Yuda M., Kinoshita K., Yoda S., Kondo Y.
IEEE Journal on Selected Topics in Quantum Electronics 13 ( 5 ) 1295 - 1301 2007.9
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Journal on Selected Topics in Quantum Electronics
We have developed high-performance 1.3-μm-band laser diodes on an InGaAs ternary substrate with a low indium content (In:0.1) grown by a novel bulk crystal growth technique called the traveling liquidus-zone (TLZ) method. This laser has a long-wavelength lasing of 1.28 μm and provides lasing operation up to 195°C by using a highly strained InGaAs quantum well. The characteristic temperatures are 130 K from 25 to 95°C and 95 K from 95 to 155°C. We investigated junction heating by comparing the lasing wavelengths for pulsed and continuous-wave (CW) operation. And, we showed the possibility of realizing a high-performance laser on an InGaAs ternary substrate. © 2007 IEEE.
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Arai M., Watanabe T., Yuda M., Kinoshita K., Ogata Y., Yoda S., Kondo Y.
Conference Digest - IEEE International Semiconductor Laser Conference 157 - 158 2006.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Digest - IEEE International Semiconductor Laser Conference
We have developed high-performance 1.3 μm-band laser diodes on an InGaAs ternary substrate with a low indium content (In: 0.1) grown by a novel bulk crystal growth technique (TLZ method). This laser operates at a long wavelength of 1.28 μm and at temperatures up to195 °C by using a highly strained InGaAs quantum well. The characteristic temperatures are 130 K from 25 to 95 °C and 95 K from 95 to 155°C. © 2006 IEEE.
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Ariga M., Arai M., Kageyama T., Setiagung C., Ikenaga Y., Iwai N., Shimizu H., Nishikata K., Kasukawa A., Koyama F.
IEEE Journal on Selected Topics in Quantum Electronics 11 ( 5 ) 1074 - 1078 2005.9
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Journal on Selected Topics in Quantum Electronics
The behavior of relative intensity noise of GaInNAsSb 1300-nm-range vertical-cavity surface-emitting lasers (VCSELs) is presented for the first time. The relative intensity noise drastically increases beyond a critical optical feedback. It was theoretically and experimentally found that the increase of relaxation oscillation frequencies was effective for the sensitivity of the optical feedback in the single-mode long-wavelength VCSELs. In our experiment, the critical feedback levels were -32 and -29 dB when frequencies were 4.0 and 5.8 GHz. This result is in good agreement with a theory.
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Kondo T., Arai M., Matsutani A., Miyamoto T., Koyama F.
Conference on Optical Fiber Communication, Technical Digest Series 2 74 - 76 2004.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference on Optical Fiber Communication, Technical Digest Series
We demonstrate 10 Gb/s single mode fiber data transmission using an uncooied 1.12 μn GalnAs/GaAs QW VCSEL with optical feedback. Isolator-free operation with-24 dB optical feedback is successfully demonstrated for the first time.
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Noise characteristics of GaInNAsSb 1.3μm-range VCSEL with optical feedback for isolator-free module
Ariga M., Kageyama T., Setiagung C., Ikenaga Y., Kumada K., Hama T., Iwai N., Shimizu H., Nishikata K., Kasukawa A., Arai M., Koyama F.
Conference Digest - IEEE International Semiconductor Laser Conference 87 - 88 2004.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Digest - IEEE International Semiconductor Laser Conference
The reflection-noise characteristics of 1.3μm-range VCSELs are presented for the first time. It is theoretically and experimentally found that the increase of relaxation-oscillation-frequencies was effective for the sensitivity of optical feedback in single-mode long-wavelength VCSELs. © 2004 IEEE.
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A thermally tunable GaAlAs-GaAs micromachined optical filter with submillisecond tuning speed
Amano T., Hino T., Koyama F., Arai M., Matsutani A.
IEEE Photonics Technology Letters 16 ( 6 ) 1501 - 1503 2004.6
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Photonics Technology Letters
We fabricated a GaAlAs-GaAs thermally tunable vertical-cavity filter with a thermal strain control layer and heating element on a micromachined cantilever structure. We achieved a large negative temperature dependence of -0.79 nm/K for the vertical-cavity filter by loading a GaAs strain control layer. The tuning voltage is as low as 4.9 V for wavelength tuning of 18.1 nm. We examined the dynamic response of the thermally tunable micromachined GaAlAs-GaAs filter, exhibiting both rise time and fall time of below 100 μs.
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Long wavelength GaInAs/GaAs VCSELs and multi-wavelength arrays
Koyama F., Arai M.
Proceedings of SPIE - The International Society for Optical Engineering 5277 146 - 154 2004.6
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Proceedings of SPIE - The International Society for Optical Engineering
We have developed highly strained GaInAs/GaAs quantum well (QW) vertical cavity surface emitting lasers (VCSELs) emitting at 1.1-1.2 μm wavelength band. Excellent temperature characteristics, enabling uncooled operations, have been realized. We successfully extended the emission wavelength of highly strained GaInAs QWs up to 1.2 mm without degradations of crystal qualities. We demonstrated uncooled low threshold current operations and high speed operations up to 10 Gb/s. We realized error-free data transmission in a standard single-mode fiber using a GaInAs single-mode VCSEL. For further upgrade of high speed LANs, we carried out the growth of highly strained GaInAs/GaAs quantum wells on a patterned substrate for realizing multiple wavelength VCSEL arrays in a wide wavelength span. We demonstrated a single-mode multiple-wavelength VCSEL array on a patterned GaAs substrate covering a new wavelength window of 1.1- 1.2 μm. By optimizing a pattern shape, we achieved multiple-wavelength operation with widely and precisely controlled lasing wavelengths. The maximum lasing span is as large as 190 nm. The multiple-wavelength array and wavelength engineering of VCSELs may open up future ultra-high capacity short reach systems.
DOI： 10.1117/12.546343
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Size Reduction of Tunable Micromachined Filters for Fast Wavelength Tuning
Amano T., Hino T., Janto W., Arai M., Koyama F.
Japanese Journal of Applied Physics, Part 2: Letters 43 ( 2 A ) 2004.2
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Applied Physics, Part 2: Letters
We present the design and fabrication of a micromachined GaAs/AlGaAs filter for fast wavelength tuning. The size reduction of tunable micromachined filters is carried out to increase the speed of wavelength tuning. We fabricated micromachined filters having a miniature filter structure with an air gap of 300 nm and a short cantilever of 45 μm length, and exhibiting a fast response time of below 2.5 μs.
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Kondo T., Arai M., Matsutani A., Miyamoto T., Koyama F.
Electronics Letters 40 ( 1 ) 65 - 66 2004.1
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Electronics Letters
Isolator-free 10 Gbit/s singlemode fibre data transmission using an uncooled 1.12 μm GaInAs/GaAs QW VCSEL with optical feedback is demonstrated for the first time. The relative intensity noise is below 130 dB/Hz even with an optical feedback of -22 dB.
DOI： 10.1049/el:20040056
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Kondo T., Arai M., Matsutani A., Miyamoto T., Koyama F.
Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS 2 501 - 502 2003.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS
A highly strained GaInAs/GaAs VCSEL emitting at 1.13 μm was demonstrated. As such, the threshold current was below 1 mA. A maximum single mode output power of over 2mW was achieved. Such reuslts indicated that a highly strained 1.1-1.2μm range GaInas VCSEL can be useful for high capacity metro-area networks.
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Amano T., Koyama F., Arai M., Matsutani A.
Japanese Journal of Applied Physics, Part 2: Letters 42 ( 11 B ) 2003.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Applied Physics, Part 2: Letters
We present the design of novel micromachined vertical-cavity light emitters/lasers with a thermal strain control layer for temperature-insensitive operations. The temperature dependence of a resonant wavelength can be freely controlled in a micromachined cantilever structure. We demonstrated a micromachined resonant-cavity light emitter with a small temperature dependence of the emission wavelength. The temperature dependence was as small as +0.015 nm/K, which is five times smaller than that of conventional single-mode lasers.
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Arai M., Kondo T., Onomura A., Matsutani A., Miyamoto T., Koyama F.
IEEE Journal on Selected Topics in Quantum Electronics 9 ( 5 ) 1367 - 1373 2003.9
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Journal on Selected Topics in Quantum Electronics
The wavelength engineering of vertical cavity surface emitting lasers (VCSEL) on a nonplanar substrate enables us to realize a multiwavelength VCSEL array. We are able to control the wavelength of both a cavity resonance and the gain peak of an active region, depending on patterned shapes. A main limiting factor in expanding the wavelength span in arrays is the offset between the gain peak and the resonant wavelength. In order to overcome this offset, we optimized a gain-cavity detuning to extend the wavelength span. A wavelength span of over 100 nm was obtained from a fabricated 12-channel array. The output power is over 1 mW, and threshold current is 0.65 ± 0.2 mA. We carried out the compensation of the threshold current-density variation by the precise control of oxide apertures in each element. In addition, we proposed a growth-pressure control in epitaxial growth on a patterned substrate for further extension of the lasing wavelength span. We demonstrated a 0.96-1.16-μm multiple-wavelength VCSEL array with highly strained GaInAs-GaAs QWs exhibiting a record wavelength span of 192 nm. These technologies would enable low-cost wideband wavelength division multiplexing data links.
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Densely integrated multiple-wavelength vertical-cavity surface-emitting laser array
Onomura A., Arai M., Kondo T., Matsutani A., Miyamoto T., Koyama F.
Japanese Journal of Applied Physics, Part 2: Letters 42 ( 5 B ) 2003.5
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Applied Physics, Part 2: Letters
We demonstrated a densely integrated multiple-wavelength GaInAs/GaAs vertical-cavity surface-emitting laser (VCSEL) array using non planar metal-organic chemical vapor deposition (MOCVD). The fabricated 1-mm-long array consists of 20-channel VCSELs and the pitch between each channel is as small as 50 μm. The lasing wavelength of each channel was precisely designed based on the relationship between the lasing wavelength and the pattern width. The wavelength spacing is within 1 nm. All VCSELs exhibited single-mode operation, an output power of over 1.2 mW and a threshold current of 0.52 ± 0.1 mA.
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Design and fabrication of GaAs-GaAlAs micromachined tunable filter with thermal strain control
Amano T., Koyama F., Hino T., Arai M., Mastutani A.
Journal of Lightwave Technology 21 ( 3 ) 596 - 601 2003.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Lightwave Technology
In this paper, we present the design and fabrication of a novel GaAlAs-GaAs micromachined vertical Cavity filter with a thermal strain control layer for wide wavelength tuning. The integration of a thermal strain control layer and heating element enables wavelength tuning induced by heating. The proposed tunable filter under thermal tuning operation provides Us large tuning range over conventional micromachined tunable filters using electrostatic force. The calculated result shows a possibility of large continuous tuning range of over 100 nm. We fabricated a micromachined GaAlAs-GaAs vertical cavity filter with a strain control layer. The temperature dependence of the filter can be freely controlled either with temperature insensitive operation or with an enhanced temperature dependence, which depends on the thickness of the thermal strain control layer. We demonstrate a thermal wavelength tuning of 53 nm with a low tuning voltage of 6.1 V for the first time.
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Micromachined resonant cavity light emitter with low temperature dependence of emission wavelength
Amano T., Koyama F., Arai M., Mastutani A.
Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest 1 2003
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest
We present the design and the fabrication of novel micromachined vertical-cavity light emitters/lasers with a thermal strain control layer for temperature insensitive operations. The temperature dependence of a resonant wavelength can be freely controlled in a michromachined cantilever structure. We demonstrated a micromachined resonant cavity light emitter with a low temperature dependence of an emission wavelength. The temperature dependence was as small as + 0.015 nm/K.
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Arai M., Kondo T., Matsutani A., Miyamoto T., Koyama F.
Device Research Conference - Conference Digest, DRC 2003-January 153 - 154 2003
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Device Research Conference - Conference Digest, DRC
© 2003 IEEE. In this paper, we propose a growth pressure control during MOCVD growth of VCSEL wafers on a patterned substrate to avoid the mismatch between a grain peak and resonant mode. We demonstrate a multiple wavelength GaInAs/GaAs VCSEL array emitting in a new wavelength window of 0.9-1.2 μm, exhibiting a record wavelength span of 192 nm.
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Multi-oxide layer vertical-cavity surface-emitting lasers with improved modulation bandwidth
Azuchi M., Jikutani N., Arai M., Kondo T., Koyama F.
Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest 1 2003
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest
We demonstrated VCSELs with multi-oxide layers (MOX) to reduce parasitic capacitance for high speed modulation beyond 10 GHz. We achieved a small signal modulation bandwidth of 11 GHz while that of a conventional single oxide layer VCSEL is 7 GHz.
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1.23μm long wavelength highly strained GaInAs/GaAs quantum well laser
Kondo T., Arai M., Onomura A., Miyamoto T., Koyama F.
Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS 2 618 - 619 2002.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS
An attempt was made to extend the emission wavelength of highly strained GaInAs/GaAs SQW over 1.2 μm under growing at a high growth rate of 9 μm/h. The longest Pl peak wavelength of 1.27 μm was obtained. A highly strained GaInAs/GaAs SQW stripe-laser was also demonstrated. The lasing wavelength reached 1.23 μm with a threshold current density of 1.7 kA/cm2.
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Dynamic response of thermally tunable micromachined optical filter with low tuning voltage
Amano T., Hino T., Koyama F., Arai M., Matsutani A.
Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS 2 829 - 830 2002.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS
An overview is given of some tuning characteristics of a GaAlAs/GaAs micromachined tunable filter with integrating a thermal strain control layer and heating element on a top surface. The design of micromachined filters for wide tuning range and for fast wavelength tuning is presented. Experimentally, the fast tuning response with rise time and fall time of below 100 μs is demonstrated.
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Densely integrated multiple-wavelength vertical cavity surface emitting laser array
Onomura A., Arai M., Kondo T., Matsutani A., Miyamoto T., Koyama F.
Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS 2 689 - 690 2002.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS
The operation of a 20-ch densely integrated multiple wavelengths VCSEL array on a patterned GaAs substrate was followed. All VCSELs exhibited single mode operation, and output power of over 1.2mW, and the threshold current of 0.52±0.1 mA. The result shows a possibility of large scale multiple-wavelength sources densely packed in a small chip.
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1200 nm highly strained GaInAs/GaAs surface emitting lasers
Koyama F., Miyamoto T., Arai M., Kondo T.
Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS 1 271 - 272 2002.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS
Low threshold current density operations of highly strained GaInAs/GaAs QW lasers emitting at nearly 1.2 μm wavelength was demonstrated. It was realized that 1.2 μm uncooled vertical cavity surface emitting lasers (VCSELs) and multiple-wavelength arrays including their use in single mode fiber data transmission. This paper reviews the results on 1.2 μm GaInAs/GaAs VCSELs including their temperature lasing characteristics and wavelength engineering on patterned substrates.
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Singlemode fibre transmission using 1.2 μm band GaInAs/GaAs surface emitting laser
Kondo T., Arai M., Azuchi M., Uchida T., Matsutani A., Miyamoto T., Koyama F.
Electronics Letters 38 ( 16 ) 901 - 903 2002.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Electronics Letters
Singlemode fibre (SMF) transmission using a 1.2 μm band GaInAs/GaAs vertical cavity surface emitting laser (VCSEL) is demonstrated. It was observed that the short optical pulse with a pulse width of 60 ps was compressed to 50 ps after transmitting in a 10 km-long SMF due to the frequency chirp of a VCSEL and the negative fibre dispersion at 1.2 μm. This result indicates that this new wavelength window would enable high bit rate data transmission beyond 10 Gbit/s without chirp penalties.
DOI： 10.1049/el:20020598
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GaAlAs/GaAs micromachined thermally tunable vertical cavity filter with low tuning voltage
Amano T., Koyama F., Arai M.
Electronics Letters 38 ( 14 ) 738 - 740 2002.7
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Electronics Letters
A GaAlAs/GaAs micromachined thermally tunable vertical cavity filter with a low tuning voltage is proposed and its fabrication described. The integration of a thermal strain control layer and heating element enables wavelength tuning induced by heating. Wavelength tuning of 23.2 nm with a low tuning voltage of 4.7 V is demonstrated experimentally.
DOI： 10.1049/el:20020490
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Arai M., Kondo T., Matsutani A., Miyamoto T., Koyama F.
IEEE Journal on Selected Topics in Quantum Electronics 8 ( 4 ) 811 - 816 2002.7
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Journal on Selected Topics in Quantum Electronics
We carried out the growth of highly strained GaInAs-GaAs quantum wells (QWs) on a patterned substrate for extending an emission wavelength on a GaAs substrate. We examined the shift of photoluminescence wavelength of the QWs and show a large wavelength shift due to the spatial modulation in well thickness and indium composition. We demonstrated a single-mode multiple-wavelength vertical-cavity surface-emitting laser (VCSEL) array on a patterned GaAs substrate covering a new wavelength window of 1.1-1.2 μm. By optimizing a pattern shape, we achieved multiple-wavelength operation with widely and precisely controlled lasing wavelengths. The maximum lasing span is as large as 77 nm. We carried out a data transmission experiment through a 5-km single-mode fiber with 2.5 Gb/s/channel. The total throughput reaches 10 Gb/s. The VCSEL-based wavelength-division-multiplexing (WDM) source would be a good candidate for WDM-LAN beyond 10 Gb/s.
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Kondo T., Arai M., Azuchi M., Uchida T., Matsutani A., Miyamoto T., Koyama F.
Japanese Journal of Applied Physics, Part 2: Letters 41 ( 5 B ) 2002.5
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Applied Physics, Part 2: Letters
We demonstrate highly strained GaInAs/GaAs quantum well (QW) vertical cavity surface emitting lasers (VCSELs) emitting at 1.16 μm with a low threshold current density and high efficiency in the 1.2-μm-wavelength band. The VCSEL structure was monolithically grown on a (100) n-type GaAs substrate by low-pressure metalorganic vapor phase epitaxy (MOVPE). The threshold current is 3 mA for a 10 × 10 μm2 oxide aperture device, corresponding to a threshold current density of 3 kA/cm2. The maximum output power ismore than 2 mW. The maximum CW operating temperature is 85°C and the threshold current is almost constant in temperature range of 25-75°C.
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Single high-order transverse mode surface emitting laser with micromachined surface relief
Shinada S., Koyama F., Nishiyama N., Arai M.
IEICE Transactions on Electronics E85-C ( 4 ) 995 - 1000 2002.4
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEICE Transactions on Electronics
We demonstrate a single high-order transverse mode surface emitting laser (VCSEL) with narrow trenches formed on a top surface. The design and the fabrication of a single high-order mode 850 nm GaAs VCSEL with micromachined surface relief are presented. Stable single-mode operation with a side-mode suppression ratio of over 40 dB was obtained in an entire measured current range. We obtained the maximum single mode power of over 3.5 mW and a record low series resistance of below 50 Ω. In addition, a single-lobe far field pattern is demonstrated even under high-order transverse mode operation by loading phase-shift on the top surface. A coupling efficiency with optical fibers is dramatically improved.
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1.4 μm GaInNAs/GaAs quantum well laser grown by chemical beam epitaxy
Ikenaga Y., Miyamoto T., Makino S., Kageyama T., Arai M., Koyama F., Iga K.
Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers 41 ( 2 A ) 664 - 665 2002.2
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
The room-temperature pulsed operation of GaInNAs/GaAs double quantum well (DQW) lasers emitting at 1.4 μm grown by chemical beam epitaxy (CBE) with increased nitrogen composition was demonstrated. An increased threshold current density was observed with respect to a 1.3 μm GaInNAs laser due to degradation of the crystal quality. The results showed that the long-wavelength lasers beyond 1.3 μm can be obtained by improving the crystal quality.
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Optical near field by vertical cavity surface emitting laser
Shinada S., Koyama F., Nishiyama N., Arai M., Matsutani A., Goto K., Iga K.
Electronics and Communications in Japan, Part II: Electronics (English translation of Denshi Tsushin Gakkai Ronbunshi) 85 ( 2 ) 43 - 53 2002.2
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Electronics and Communications in Japan, Part II: Electronics (English translation of Denshi Tsushin Gakkai Ronbunshi)
Our research examines the generation of an optical near field by a vertical cavity surface emitting laser (VCSEL), which can readily be formed into a two-dimensional array, and the possible application to optical recording capable of high-speed data transfers due to the higher density and parallel processing achieved when the optical near field is used as the optical head. We propose a VCSEL with metal micro-aperture for generating the optical near field. Then we demonstrate the ability to create a micro spot size of 100 nm or smaller based on this structure from analysis of the intensity distribution of the micro-aperture by the two-dimensional finite element method. We also form a micro-aperture by using a focused ion beam in a GaAs/AlGaAs VCSEL with an 850-nm wavelength and perform initial evaluations. In these evaluations, we obtained an emitted power density of 0.12 mW/μm2 from a 400-nm square micro-aperture. Furthermore, we observed the light from a 100-nm square aperture in near field observations and verified the generation of an optical near field by this structure.
DOI： 10.1002/ecjb.1092
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Arai M., Kondo T., Azuchi M., Uchida T., Matsutani A., Miyamoto T., Koyama F.
Conference Proceedings - International Conference on Indium Phosphide and Related Materials 303 - 306 2002
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Proceedings - International Conference on Indium Phosphide and Related Materials
We demonstrated a single-mode multiple wavelength VCSEL array with highly strained GaInAs/GaAs QWs on a patterned GaAs substrate in a new wavelength band of 1.1-1.2 μm. The emission wavelength of a 4-channel array ranges from 1137 nm to 1144 nm. We carried out data transmission experiment through a 5 km single mode fiber with 2.5 Gbps/channel. The total throughput reaches at 10 Gbps. This novel WDM source would be a good candidate for WDM-LAN beyond 10 Gbps. In addition, we show a potential extension of the wavelength span for multiple wavelength VCSEL arrays by optimizing the pattern shape of a substrate.
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Arai M., Kondo T., Matsutani A., Miyamoto T., Koyama F.
Conference Digest - IEEE International Semiconductor Laser Conference 9 - 10 2002
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Digest - IEEE International Semiconductor Laser Conference
A multiple-wavelength vertical-cavity surface emitting lasers (VCSEL) array with highly strained GaInAs/GaAs quantum wells (QA) was studied. The VCSEL array is emitting in a new wavelength window of 1.0-1.2 μm exhibiting a record wavelength span of over 100 nm. It was found that the lasers exhibit an output power of over 1 mW and the threshold current is 0.65±0.2 mA.
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GaAlAs/GaAs micromachined tunable vertical filter with low tuning voltage below 5 volts
Amano T., Koyama F., Hino T., Arai M., Matsutani A.
Device Research Conference - Conference Digest, DRC 2002-January 143 - 144 2002
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Device Research Conference - Conference Digest, DRC
© 2002 IEEE. MEMS based tunable filters and vertical cavity surface-emitting lasers (VCSELs) are attracting much interest because of their unique features, such as wide continuous tuning, polarization insensitive operation and 2-dimensional array integration. There remain difficulties in tuning range and tuning voltage of such MEMS based filters using electrostatic force because a micromachined cantilever is pulled down by an electrostatic force and its actual allowed movement is limited to be 1/3 of the air gap width. Also, a tuning voltage is typically several tens of volts. In this paper, we propose and demonstrate a GaAlAs/GaAs micromachined tunable filter with a thermal strain control layer and a heating element, which enable low tuning voltage. We present the design of thermally tunable filters with a tuning range of over 300 nm. Experimentally, we demonstrate wavelength tuning of a thermally tunable MEMS filter, which shows a record low tuning voltage of 4.7 V for tuning range of 23.2 nm.
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Temperature characteristics of 1.16 μm highly strained GaInAs/GaAs VCSELs
Kondo T., Arai M., Nishiyama N., Azuchi M., Matsutani A., Miyamoto T., Koyama F., Iga K.
Proceedings of SPIE - The International Society for Optical Engineering 4649 39 - 49 2002
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Proceedings of SPIE - The International Society for Optical Engineering
We demonstrated highly strained GaInAs/GaAs QW VCSELs emitting at 1.16 μm. The fabricated device shows a record low threshold current density and high efficiency in the 1.2 μm wavelength band. The VCSEL structure was monolithically grown on a (100) n-type GaAs substrate by a low-pressure metalorganic vapor phase epitaxy (MOVPE). The active region consists of 8 nm thick Ga0.64In0.36As TQWs separated by 25 nm GaAs barrier layers. The compressive strain of QWs is 2.3%. The threshold current is 3 mA for a 10 μm ∼10 μm oxide device, corresponding to a threshold current density of 3 kA/cm2. We achieved the maximum output power of over 2 mW and a slope efficiency of 0.3 W/A at 25°C, which are the record data for 1.2 μm band GaInAs VCSELs. The maximum CW operating temperature is 85°C. The threshold current is almost constant in the temperature range of 20-70°C which results from appropriate wavelength matching between the gain peak and lasing mode. The temperature dependence of the lasing wavelength is 0.07 nm/K. The details of their device fabrication and lasing characteristics are discussed. © 2002 SPIE · 0277-786X/01/$15.00.
DOI： 10.1117/12.469248
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Arai M., Kondo T., Nishiyama N., Matsutani A., Miyamoto T., Koyama F., Iga K.
Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS 2 600 - 601 2001.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS
The metallorganic chemical vapor deposition (MOCVD) growth of multiple wavelength vertical cavity surface emitting laser (VCSEL) array was demonstrated using patterned substrate. The single-mode VCSEL array was with highly strained GaInAs quantum well (QW) on a patterned GaAs substrate. A patterned substrate having a wedge shaped mesa was prepared by standard photolithography followed by wet etching. The obtained emission wavelength of a 16-channel array ranged from 1116 nm to 1154 nm.
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Arai M., Nishiyama N., Azuchi M., Matsutani A., Koyama F., Iga K.
Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest 2 2001.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest
We have investigated the modulation characteristic of a highly strained GaInAs/GaAs vertical cavity surface emitting laser. This laser exhibits stable polarization operation and an emitting wavelength is 1125 nm. The eye pattern after 5 km single-mode fiber transmission was clearly opened under 1 Gbits/s modulation speed.
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Micromachined GaAlAs/GaAs vertical cavity tunable filter with enhanced thermal tuning range
Amano T., Koyama F., Arai M., Miyamoto T., Iga K.
European Conference on Optical Communication, ECOC 2 216 - 217 2001.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：European Conference on Optical Communication, ECOC
We have proposed a novel micromachined vertical cavity tunable filter with a thermal strain control layer, which enables wavelength tuning induced by heating. We show a possibility of a large tuning range of over 100 nm. Experimentally, we demonstrate both of negative and positive wavelength tuning for micromachined GaAlAs/GaAs filters.
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Shinada S., Nishiyama N., Arai M., Koyama F.
Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS 2 564 - 565 2001.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS
A single-lobe far field pattern of a GaAs single high-order mode vertical cavity surface emitting laser (VCSEL) was demonstrated with surface micromachined relief. A π-phase shift in partially etched surface resulted in a single-lobe far field pattern using a focussed ion beam (FIB). The mode stability of VCSEL under high speed modulation was also discussed. A fiber coupling efficiency was observed to be improved with the introduction of the phase-shift on the surface.
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Single high-order transverse mode 850 nm VCSEL with micromachined surface relief
Shinada S., Koyama F., Nishiyama N., Arai M., Iga K.
Conference on Lasers and Electro-Optics Europe - Technical Digest 106 - 107 2001.10
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference on Lasers and Electro-Optics Europe - Technical Digest
Stable high order mode GaAs vertical cavity surface emitting lasers (VCSEL) was achieved with surface micromachined relief. Eight straight trenchers crossing each other on the top surface were fabricated to give excess reflection loss. Focused ion beam was used for surface micromachining to form 14 μm long and 500 nm wide trenches. The fabricated device showed stable single high order transverse mode operation under modulation and a low resistance of below 50 ω was obtained due to large oxide aperture.
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Arai M., Nishiyama N., Azuchi M., Matsutani A., Koyama F., Iga K.
Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers 40 ( 6 A ) 4056 - 4057 2001.6
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
We have demonstrated the monolithic integration of multi-wavelength vertical cavities with highly strained GaInAs/GaAs quantum wells on a patterned GaAs (311)B substrate. Using a patterned substrate, the resonant wavelength can be controlled in the range from 1.13 μm to 1.145 μm. The obtained result may open up the field of multi-wavelength surface emitting lasers emitting in the 1.1-1.2 μm band enabling their use in wavelength division multiplexing local area networks (WDM-LANs).
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Nishiyama N., Arai M., Shinada S., Azuchi M., Matsutani A., Miyamoto T., Koyama F., Iga K.
Japanese Journal of Applied Physics, Part 2: Letters 40 ( 5 A ) 2001.5
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Applied Physics, Part 2: Letters
A highly strained GaInAs vertical-cavity surface-emitting laser (VCSEL) emitting at 1.12 μm has been realized on a GaAs(311)B substrate by metal organic chemical vapor deposition (MOCVD) for the first time. The threshold current of an 8 μm oxide aperture device was as low as 0.9 mA. This device operated at up to 170°C without a heatsink under the CW condition. The polarization direction of the oscillation mode was stable and the orthogonal polarization suppression ratio (OPSR) was 30 dB. The operating lifetime of over 2000 under room-temperature CW conditions was confirmed without any degradation in spite of high strain of over 2%.
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Shinada S., Koyama F., Nishiyama N., Arai M., Iga K.
IEEE Journal on Selected Topics in Quantum Electronics 7 ( 2 ) 365 - 370 2001.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Journal on Selected Topics in Quantum Electronics
We have proposed a microaperture vertical cavity surface-emitting laser (VCSEL) for use in near-field optical data storage. We carried out the near-field analysis of microaperture VCSEL using two-dimensional (2-D) finite element method. We calculated the distribution of optical near-field generated near a microaperture, and showed that the spot size is potentially smaller than 100 nm, which is less than wavelength by a factor of 8. We fabricated a VCSEL loaded by an Au film on the top surface for blocking the emitting light and formed a subwavelength-size aperture using focused ion beam (FIB) etch through this film. Single-mode operation was obtained for a microaperture VCSEL with 3-μm square active region. The differential quantum efficiency was increased by a factor of 3 in comparison with that before forming a 400-nm square aperture. We estimated the power density of light radiated from a 400-nm square aperture to be 0.17 mW/μm2. In addition, we measured the near-field distribution of a 200-nm square aperture VCSEL by using a scanning near-field microscope.
DOI： 10.1109/2944.954151
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Nishiyama N., Arai M., Shinada S., Azuchi M., Miyamoto T., Koyama F., Iga K.
IEEE Journal on Selected Topics in Quantum Electronics 7 ( 2 ) 242 - 248 2001.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Journal on Selected Topics in Quantum Electronics
We have realized high-quality GaInAs-GaAs quantum wells (QWs) with high strain of over 2% on GaAs (311)B substrate for a polarization controlled vertical-cavity surface-emitting laser (VCSEL). By increasing the composition in GaInAs, the optical anisotropy in photoluminescence (PL) intensity was increased. The anisotropy of 50% was obtained at 1.15 μm emission wavelength. We have demonstrated edge-emitting lasers and VCSELs emitting at over 1.1 μm on GaAs (311)B substrate for the first time. The 1.15-μm edge-emitting laser showed a characteristic temperature of 210 K and the threshold current density of 410 A/cm2. The threshold current and lasing wavelength of VCSELs are 0.9 mA and 1.12 μm, respectively. The orthogonal polarization suppression ratio was 25 dB and CW operation up to 170°C without a heat sink was achieved.
DOI： 10.1109/2944.954136
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GaInAs/GaAs single mode vertical cavity surface emitting laser (VCSEL) array on GaAs (311)B
Arai M., Nishiyama N., Azuchi M., Shinada S., Matsutani A., Koyama F., Iga K.
IEICE Transactions on Electronics E84-C ( 3 ) 331 - 338 2001.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEICE Transactions on Electronics
We have demonstrated a dynamically stable polarization operation of GaInAs/GaAs vertical-cavity surface-emitting laser (VCSEL) array grown on a GaAs (311)B substrate. A fabricated 3 × 3 VCSEL array consists of devices with an oxide aperture of 3.4 μm × 3.4μm. The threshold current was 0.61 ± 0.05 mA and the threshold voltage was 1.79 ± 0.03V. All of the devices exhibited single-transverse mode operation with an injection current up to three times the threshold. The side-mode suppression ratio (SMSR) is larger than 30 dB. The array also exhibited stable-polarization operation with an orthogonal polarization suppression ratio (OPSR) of over 25 dB. We measured the time-resolved OPSR under square-wave direct modulation. It was found that the orthogonal non-lasing mode was suppressed even at the first peak of relaxation oscillation with OPSR > 17 dB. In an experiment of 5 Gb/s non-return-to-zero (NRZ) pseudo-random bit sequence (PRBS) modulation, the OPSR was maintained being greater than 27 dB. These observed stable and single polarization characteristics were originated from the anisotropic optical gain of strained GaInAs/GaAs quantum wells formed on (311)B substrate. We also carried out an intensity noise measurement under single-transverse and stable polarization operation for the first time. The relative intensity noise (RIN) of -140 dB/Hz was obtained. In addition, we achieved 2.5 Gb/s data transmission through a 100m multi-mode fiber. No error floor was observed at -20dBm of received power level. The minimum received power is determined by the thermal noise.
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AlAs oxidation system with H2O vaporizer for oxide-confined surface emitting lasers
Arai M., Nishiyama N., Shinada S., Koyama F., Iga K.
Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers 39 ( 6 A ) 3468 - 3469 2000.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
We have developed an oxidation apparatus with high reproducibility for fabricating oxide-confined vertical cavity surface emitting lasers (VCSELs). Precise control of AlAs oxidation can be realized for a high-performance VCSEL array in mass production. In this system, we introduce a vaporizer with a water mass flow controller for stable and precise control of H2O vapor. We have achieved good reproducibility and controllability. The run-to-run deviation of the oxidized window is ±0.1 μm for nominal ∼10.4 μm oxidation. © 2000 The Japan Society of Applied Physics.
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Arai M., Nishiyama N., Shinada S., Matsutani A., Koyama F., Iga K.
Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS 2 728 - 729 2000.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS
Several 960 nm single-mode vertical-cavity surface-emitting laser (VCSEL) arrays were grown on a GaAs (311)B substrate. All the devices in a 3 × 3 array exhibited single-transverse-mode and stable-polarization operation in an entire injection current range.
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Near-field characterization of micro-aperture surface emitting laser for near field data storage
Shinada S., Koyama F., Nishiyama N., Arai M., Iga K.
Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS 2 896 - 897 2000.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS
A 400 nm square micro-aperture VCSEL with single transverse mode operation was fabricated. Near field characterization was carried out using a sharpened fiber probe. The FWHM of intensity below threshold was 250 nm.
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Koyama F., Amano T., Furukawa N., Nishiyama N., Arai M., Iga K.
Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers 39 ( 3 B ) 1542 - 1545 2000.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
We propose a micromachined vertical cavity resonator enabling temperature insensitive operation for surface emitting lasers or optical add/drop filters. The strain-induced displacement from differential thermal expansion is used to compensate the wavelength shift caused by temperature variation. Also, a wavelength-trimming technology using the same principle with precise strain control is suggested. The possibility of a drastic reduction in the temperature sensitivity of wavelengths, as well as precise wavelength adjustment, is presented. We fabricated a micromachined vertical cavity filter with a GaAlAs/GaAs multilayer reflector, which is mechanically tuned by differential thermal expansion. We observed a large negative temperature coefficient of the resonant wavelength. It is demonstrated that its temperature dependence can be widely controlled by the proposed concept. The possibility of temperature-insensitive operation is discussed. ©2000 Publication Board, Japanese Journal of Applied Physics.
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Nishiyama N., Arai M., Shinada S., Miyamoto T., Koyama F., Iga K.
Conference Digest - IEEE International Semiconductor Laser Conference 11 - 12 2000.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Conference Digest - IEEE International Semiconductor Laser Conference
The first lasing operation of 1.12 μm highly strained GaInAs/GaAs quantum well vertical cavity surface emitting lasers (VCSEL) on a GaAs (113)B substrate is demonstrated. These lasers are viable for LANs with a link length of several km or longer. The wells have the In content of 33% and 2.3% strain. The threshold current is 0.9 mA. These VCSELs also show large polarization stability with orthogonal suppression ratio (OPSR) of 25 dB.
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Growth and optical properties of highly strained GaInAs/GaAs quantum wells on (3 1 1)B GaAs by MOCVD
Nishiyama N., Arai M., Shinada S., Miyamoto T., Koyama F., Iga K.
Journal of Crystal Growth 221 ( 1-4 ) 530 - 534 2000.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Crystal Growth
We have investigated some characteristics of highly strained GaInAs/GaAs quantum wells grown on GaAs (3 1 1)B substrate by metal organic chemical vapor deposition (MOCVD) for the enhancement of polarization stabilities of vertical-cavity surface-emitting lasers (VCSELs). Quantum wells (QWs) with an In composition of over 30% have been grown without any degradation in crystal properties. We have achieved an emission wavelength of 1.16 μm (In = 35%) with a full-width at half-maximum of 20 meV and found that the optical intensity anisotropy between the orthogonal directions of [2̄ 3 3̄] and [0 1̄ 1 ̄] was increased to be 50% for QWs with 33% In.
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Sato S., Nishiyama N., Miyamoto T., Takahashi T., Jikutani N., Arai M., Matsutani A., Koyama F., Iga K.
Electronics Letters 36 ( 24 ) 2018 - 2019 2000.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Electronics Letters
Electrically pumped near 1.3μm GaInNAs/GaAs vertical-cavity surface-emitting lasers grown by metalorganic chemical vapour deposition are demonstrated for the first time. The threshold current and voltage under continuous wave operation of a 10 × 10μm2 oxide aperture device were 7.6mA and 2.8V, respectively. The output power exceeded 0.1 mW and the slope efficiency was approx. 0.1 W/A.
DOI： 10.1049/el:20001430
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Nishiyama N., Arai M., Shinada S., Miyamoto T., Koyama F., Iga K.
Japanese journal of applied physics 39 ( 10 B ) 2000.10
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese journal of applied physics
We have demonstrated a λ = 1.15 μm highly strained GaInAs/GaAs quantum well laser grown on GaAs (311)B substrate for the first time. The threshold current density of double quantum well lasers was as low as 410 A/cm2 and the characteristic temperature in the operating temperature range from 10°C to 70°C was 210K. Wavelength extension to near 1.3 μm and improved polarization stability of vertical-cavity surface-emitting lasers (VCSELs) formable on GaAs substrate can now be expected.
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Arai M., Nishiyama N., Shinada S., Matsutani A., Koyama F., Iga K.
Japanese Journal of Applied Physics, Part 2: Letters 39 ( 8 B ) 2000.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Applied Physics, Part 2: Letters
We have demonstrated a dynamically stable polarization mode GaInAs/GaAs vertical-cavity surface-emitting laser (VCSEL) grown on a GaAs (311)B substrate. The fabricated device exhibited a stable and single polarization under DC and high-speed modulation. Under DC operation, the orthogonal polarization suppression ratio (OPSR) was larger than 30 dB. We measured the time-resolved OPSR using square-wave modulation. It was found that the orthogonal mode was suppressed even for the first peak of the relaxation oscillation with OPSR>17 dB. In a 5 Gbps non-return-to-zero (NRZ) pseudo-random bit sequence (PRBS) modulation experiment, the OPSR was greater than 27 dB. These stable and single polarization characteristics were due not only to the anisotropic optical gain on a (311)B substrate, but also strained GaInAs/GaAs quantum wells and the thin oxide layer which was employed in this experiment.
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Multi-oxide layer structure for single-mode operation in vertical-cavity surface-emitting lasers
Nishiyama N., Arai M., Shinada S., Suzuki K., Koyama F., Iga K.
IEEE Photonics Technology Letters 12 ( 6 ) 606 - 608 2000.6
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Photonics Technology Letters
We propose a novel vertical-cavity surface emitting laser (VCSEL) with Al(Ga)As multi-oxide layer (MOX) structure for the purpose of enlarging window aperture maintaining single transverse mode operation. We have fabricated an InGaAs-GaAs VCSEL with the proposed MOX structure formed on GaAs (311)B substrate. We have performed a numerical simulation to investigate single-mode behavior of the proposed structure and showed a possibility of single-mode VCSEL's with a large active area. We have fabricated an 11-μm current aperture 960-nm wavelength VCSEL with this MOX structure. The threshold current and voltage were 1.0 mA and 2.0 V, respectively, which are comparable to those of conventional oxide VCSEL's. In 8-μm aperture, single-mode operation was maintained with a driving current up to four times the threshold.
DOI： 10.1109/68.849058
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Arai M., Nishiyama N., Shinada S., Matsutani A., Koyama F., Iga K.
Japanese Journal of Applied Physics, Part 2: Letters 39 ( 6 B ) 2000.6
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Applied Physics, Part 2: Letters
We have demonstrated a single-transverse-mode and stable-polarization GaInAs/GaAs vertical-cavity surface-emitting laser (VCSEL) array grown on a GaAs(311)B substrate. A fabricated 3×3 VCSEL array consists of devices with an oxide aperture of 3.4 μm×3.4 μm and exhibited single-transverse mode operation with an injection current up to three times the threshold. The Side-mode suppression ratio (SMSR) is larger than 30 dB. The array also exhibits stable-polarization operation with an orthogonal polarization suppression ratio (OPSR) of over 25 dB. The threshold current was 0.61±0.05 mA and the threshold voltage was 1.79±0.03 V. The obtained uniform single-mode array characteristics are due to the high uniformity and controllability of the improved oxidation process.
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Fabrication of micro-aperture surface emitting laser for near field optical data storage
Shinada S., Koyama F., Nishiyama N., Arai M., Goto K., Iga K.
Japanese Journal of Applied Physics, Part 2: Letters 38 ( 11 B ) 1999.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Applied Physics, Part 2: Letters
We fabricated a micro-aperture vertical cavity surface emitting laser (VCSEL) for use in near field optical data storage. A composite mirror of Au and a 11-pair semiconductor distributed Bragg reflector (DBR) provides a reflectivity of more than 99%. Fabricated VCSEL devices exhibited sub-mA low threshold operation. A micro-aperture with a diameter below 400 nm was introduced in Au film using focused ion beam etching. A localized near field at a 400 nm aperture was observed and the output power from the aperture was estimated to be 10 μW.
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Nishiyama N., Mizutani A., Hatori N., Arai M., Koyama F., Iga K.
IEEE Journal on Selected Topics in Quantum Electronics 5 ( 3 ) 530 - 536 1999.5
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Journal on Selected Topics in Quantum Electronics
We have demonstrated an oxide confinement polarization controlled vertical-cavity surface-emitting laser (VCSEL) grown on a GaAs (311)B substrate. The polarization state was well controlled along the [2̄33] crystal direction due to an anisotropic gain in the (311)B plane. We fabricated a small oxide aperture VCSEL with a threshold of 260 μA and realized single-transverse mode and single-polarization operation for the first time. The sidemode suppression ratio (SMSR) was 35 dB and the orthogonal polarization suppression ratio (OPSR) was 25 dB. In addition, we have measured polarization and transverse mode characteristics of multi- and single-transverse mode devices under high-speed modulation. In the multimode device of 12 μm × 12 μm oxide aperture, we have achieved stable polarization operation of over 25-dB OPSR up to 10 Gb/s and have observed no power penalty due to polarization instability under 2.5-Gb/s pseudorandom modulation. The single-mode device showed stable single-transverse mode and polarization under the modulation condition up to 5 GHz of sinusoidal modulation. SMSR and OPSR were over 30 and 10 dB, respectively.
DOI： 10.1109/2944.788415
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Nishiyama N., Mizutani A., Hatori N., Arai M., Koyama F., Iga K.
IEEE Photonics Technology Letters 10 ( 12 ) 1676 - 1678 1998.12
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Photonics Technology Letters
We have demonstrated an oxide confinement vertical-cavity surface-emitting laser grown on a GaAs (311)B substrate, and achieved single-transverse mode and single-polarization operation in the entire tested current range. The threshold was 0.6 mA for a 2.7 μm × 2.9 μm oxide aperture. Even under high-speed modulation up to 5 GHz, the device showed stable single-transverse mode and polarization. Sidemode suppression ratio and orthogonal polarization suppression ratio were over 30 and 10 dB, respectively.
DOI： 10.1109/68.730466