Masaki Kohtoku - IEEE Xplore Author Profile

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Author details

Masaki Kohtoku

Also published under: M. Kohtoku

Publications

63

Citations

779

Publications by Year

19912021

Co-Authors:

Makoto AbeMasakazu AraiS. AraiS. BabaJ. Endo

Show All Co-Authors (112)

Masaki Kohtoku

Also published under: M. Kohtoku

Affiliation

Telecommunications & Energy Laboratories

Furukawa Electric Co.

Ltd., Chiba, Japan

Publication Topics

Coupling Loss,
Insertion Loss,
Low Loss,
Optical Amplifier,
Photonic Integrated Circuits,
Au Deposits,
Baud Rate,
Bending Radius,
Bias Voltage,
Bit Error Rate,
Chip Size,
Cladding Layer

Biography

Masaki Kohtoku received the B.E., M.E., and Ph.D. degrees from the Tokyo Institute of Technology, Tokyo, Japan, in 1989, 1991, and 2006, respectively. In 1991, he joined the NTT Photonics Laboratories, Kanagawa, Japan, where he was involved in research on InP-based monolithic integrated circuit and silica-based PLC. He is now with the NTT Device Innovation Center. His research interests include the design, fabrication, trimming, and characterization of AWGs and their integrated devices. He is a Member of the Institute of Electronics, Information and Communication Engineers of Japan and the Japan Society of Applied Physics.(Based on document published on 14 December 2016).

Publications

63

Citations

779

Publications by Year

19912021

Co-Authors:

Makoto Abe
Masakazu Arai
S. Arai
S. Baba
J. Endo

Show All Co-Authors (112)

Author's Published Works

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Showing 1-25 of 63 results

Conferences (33)

Journals (30)

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M. Kohtoku(42)
Masaki Kohtoku(21)
Y. Yoshikuni(12)
Y. Inoue(10)
S. Oku(9)
NTT Photonics Laboratories, NTT Corporation, Atsugi, Kanagawa, Japan(13)
NTT Opto-Elecronics Laboratories, Atsugi, Kanagawa, Japan(11)
NTT Photonics Laboratories, NTT Corporation, Kanagawa, Japan(5)
NTT Photonics Laboratories, Kanagawa, Japan(4)
NTT Photonics Laboratories, Atsugi, Kanagawa, Japan(3)
IEEE Photonics Technology Letters(14)
Journal of Lightwave Technology(10)
IEEE Journal of Selected Topics in Quantum Electronics(5)
Optical Fiber Communication Conference and Exhibit(3)
2005 IEEE LEOS Annual Meeting Conference Proceedings(2)
IEEE(63)
Anaheim, CA, USA(8)
Chiba, Japan(3)
San Diego, CA, USA(3)
Kobe, Japan(2)
Kyoto, Japan(2)
Coupling Loss(17)
Low Loss(14)
Mach-Zehnder Interferometer(14)
Insertion Loss(13)
Excessive Loss(11)

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Results

Compact semiconductor optical amplifier with U-turn shape deep-ridge passive waveguide for Si photonic circuits

Masahiro Yoshida;Kazuomi Maruyama;Kazuaki Kiyota;Masaki Kohtoku

2021 27th International Semiconductor Laser Conference (ISLC)

Year: 2021 | Conference Paper |

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We propose an SOA with U-turn shape deep-ridge passive waveguide for integration on a silicon photonics platform. We fabricated the U-turn waveguide with the bending radius of 75 μm, and good gain characteristics were obtained in the entire C-band.Show More

Compact semiconductor optical amplifier with U-turn shape deep-ridge passive waveguide for Si photonic circuits

Masahiro Yoshida;Kazuomi Maruyama;Kazuaki Kiyota;Masaki Kohtoku

2021 27th International Semiconductor Laser Conference (ISLC)

Year: 2021 | Conference Paper |

Transmitter-Receiver Optical Sub Assembly using Ultra-Compact Tunable DBR/Ring Laser

Kazuya Nagashima;Yozo Ishikawa;Atsushi Izawa;Masayoshi Nishita;Noritaka Matsubara;Hiroyuki Ishii;Thanakit Saeyang;Yoshihiro Ogiso;Yuta Ueda;Masaki Kohtoku

2021 Optical Fiber Communications Conference and Exhibition (OFC)

Year: 2021 | Conference Paper |

Cited by: Papers (1)

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We demonstrate a tiny optical module which integrates an ultra-compact wavelength tunable laser, InP-based transmitter and PLC-based receiver. The optical module exhibits low-insertion loss (<13.6 dB) and high bandwidth (>45 GHz) for ≥400-Gb/s coherent-optical links.Show More

Transmitter-Receiver Optical Sub Assembly using Ultra-Compact Tunable DBR/Ring Laser

Kazuya Nagashima;Yozo Ishikawa;Atsushi Izawa;Masayoshi Nishita;Noritaka Matsubara;Hiroyuki Ishii;Thanakit Saeyang;Yoshihiro Ogiso;Yuta Ueda;Masaki Kohtoku

2021 Optical Fiber Communications Conference and Exhibition (OFC)

Year: 2021 | Conference Paper |

Over 67 GHz Bandwidth and 1.5 V Vπ InP-Based Optical IQ Modulator With n-i-p-n Heterostructure

Yoshihiro Ogiso;Josuke Ozaki;Yuta Ueda;Norihide Kashio;Nobuhiro Kikuchi;Eiichi Yamada;Hiromasa Tanobe;Shigeru Kanazawa;Hiroshi Yamazaki;Yoshitaka Ohiso;Takuro Fujii;Masaki Kohtoku

Journal of Lightwave Technology

Year: 2017 | Volume: 35, Issue: 8 | Journal Article |

Cited by: Papers (133)

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We report novel high-bandwidth InP-based Mach-Zehnder modulator and in-phase/quadrature (IQ) modulators that we realized by combining an n-i-p-n heterostructure and a capacitively loaded traveling wave electrode. The extremely low electrical and optical loss structure enhances the 3-dB electro-optic bandwidth of over 67 GHz without degrading other properties such as driving voltage and optical los...Show More

Over 67 GHz Bandwidth and 1.5 V Vπ InP-Based Optical IQ Modulator With n-i-p-n Heterostructure

Yoshihiro Ogiso;Josuke Ozaki;Yuta Ueda;Norihide Kashio;Nobuhiro Kikuchi;Eiichi Yamada;Hiromasa Tanobe;Shigeru Kanazawa;Hiroshi Yamazaki;Yoshitaka Ohiso;Takuro Fujii;Masaki Kohtoku

Journal of Lightwave Technology

Year: 2017 | Volume: 35, Issue: 8 | Journal Article |

Eight-Channel Reflection-type Transversal Filter for Compact and Easy-to-Fabricate InP-Based Optical Multiplexer

Yuta Ueda;Takeshi Fujisawa;Masaki Kohtoku

Journal of Lightwave Technology

Year: 2016 | Volume: 34, Issue: 11 | Journal Article |

Cited by: Papers (10)

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We developed an eight-channel (8ch) reflection-type transversal filter (RTF) with a 9 × 9 multimode interference coupler on an InP wafer to prove channel scalability of RTFs. Fabricated two types of 8ch RTF with different sizes (1-mm and 1.5-mm long) exhibited comparable filter performance and peak wavelength fluctuation less than 1 nm, and each excess loss from a designed transmittance was about ...Show More

Eight-Channel Reflection-type Transversal Filter for Compact and Easy-to-Fabricate InP-Based Optical Multiplexer

Yuta Ueda;Takeshi Fujisawa;Masaki Kohtoku

Journal of Lightwave Technology

Year: 2016 | Volume: 34, Issue: 11 | Journal Article |

Compact InP-based optical modulator for 100-Gb/s coherent pluggable transceivers

2015 Optical Fiber Communications Conference and Exhibition (OFC)

Year: 2015 | Conference Paper |

Cited by: Papers (4)

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InP-based MZ modulators are suitable for realizing coherent pluggable transceivers. They offer compact size, low driving voltage and high performance. Targeting lower power consumption, we employed a reduced driving voltage and an athermal twin-IQ modulator.Show More

Compact InP-based optical modulator for 100-Gb/s coherent pluggable transceivers

2015 Optical Fiber Communications Conference and Exhibition (OFC)

Year: 2015 | Conference Paper |

Low Driving Voltage Operation of MZI-Type EA Modulator Integrated With DFB Laser Using Optical Absorption and Interferometric Extinction

Yuta Ueda;Takeshi Fujisawa;Shigeru Kanazawa;Wataru Kobayashi;Kiyoto Takahata;Hiroaki Sanjoh;Hiroyuki Ishii;Masaki Kohtoku

IEEE Journal of Selected Topics in Quantum Electronics

Year: 2015 | Volume: 21, Issue: 6 | Journal Article |

Cited by: Papers (12) | Patents (1)

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We have developed a novel electroabsorption modulator (EAM)-integrated distributed feedback laser (EA-DFB laser), in which an EAM functioning as an external modulator is integrated in a Mach-Zehnder interferometer (MZI). The MZI-type EAM (MZEA) modulates light intensity by both optical absorption and interferometric extinction. As a result, it improves the extinction ratio (ER) of a conventional E...Show More

Low Driving Voltage Operation of MZI-Type EA Modulator Integrated With DFB Laser Using Optical Absorption and Interferometric Extinction

Yuta Ueda;Takeshi Fujisawa;Shigeru Kanazawa;Wataru Kobayashi;Kiyoto Takahata;Hiroaki Sanjoh;Hiroyuki Ishii;Masaki Kohtoku

IEEE Journal of Selected Topics in Quantum Electronics

Year: 2015 | Volume: 21, Issue: 6 | Journal Article |

25-Gb/s Operation of Metamorfic Laser with Thin Metamorfic Buffer on GaAs Substrate

R. Nakao;M. Arai;W. Kobayashi;M. Kohtoku

2014 International Semiconductor Laser Conference

Year: 2014 | Conference Paper |

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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.Show More

25-Gb/s Operation of Metamorfic Laser with Thin Metamorfic Buffer on GaAs Substrate

R. Nakao;M. Arai;W. Kobayashi;M. Kohtoku

2014 International Semiconductor Laser Conference

Year: 2014 | Conference Paper |

Tunable Diode Laser Spectroscopy (TDLS) and Laser Light Sources

Ryoko Yoshimura;Hiromi Oohashi;Tomonari Sato;Manabu Mitsuhara;Masaki Kohtoku

2014 IEEE Photonics Society Summer Topical Meeting Series

Year: 2014 | Conference Paper |

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This paper describes tunable diode laser spectroscopy and its laser light source technologies especially for InP-based distributed feedback lasers operating in the 2-2.3 μm region. Application examples including isotope ratio analysis are also introduced.Show More

Tunable Diode Laser Spectroscopy (TDLS) and Laser Light Sources

Ryoko Yoshimura;Hiromi Oohashi;Tomonari Sato;Manabu Mitsuhara;Masaki Kohtoku

2014 IEEE Photonics Society Summer Topical Meeting Series

Year: 2014 | Conference Paper |

Athermal InP(110) twin-IQ modulator with planar single-RF electrode structure

Y. Ogiso;Y. Nakanishi;S. Kanazawa;E. Yamada;N. Kikuchi;H. Tanobe;Y. Shibata;M. Kohtoku

2014 OptoElectronics and Communication Conference and Australian Conference on Optical Fibre Technology

Year: 2014 | Conference Paper |

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We report an athermal InP IQ modulator that exhibits a low optical insertion loss, a 3-dB EO bandwidth of over 25 GHz, and 56-Gb/s×2 QPSK modulations between temperatures of 20 and 80°C.Show More

Athermal InP(110) twin-IQ modulator with planar single-RF electrode structure

Y. Ogiso;Y. Nakanishi;S. Kanazawa;E. Yamada;N. Kikuchi;H. Tanobe;Y. Shibata;M. Kohtoku

2014 OptoElectronics and Communication Conference and Australian Conference on Optical Fibre Technology

Year: 2014 | Conference Paper |

Low-Loss Cascaded Mach–Zehnder Multiplexer Integrated $25\hbox{-}{\rm Gbit}/{\rm s}\times 4\hbox{-}{\rm Lane}$ EADFB Laser Array for Future CFP4 100 GbE Transmitter

Takeshi Fujisawa;Shigeru Kanazawa;Yuta Ueda;Wataru Kobayashi;Kiyoto Takahata;Akira Ohki;Toshio Ito;Masaki Kohtoku;Hiroyuki Ishii

IEEE Journal of Quantum Electronics

Year: 2013 | Volume: 49, Issue: 12 | Journal Article |

Cited by: Papers (28) | Patents (1)

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A 4 × 25-Gb/s electroabsorption modulator integrated with a distributed feedback (DFB) laser (EADFB laser) array monolithically integrated with a low-loss optical multiplexer (MUX) is developed for 100 GbE transmitters for the first time. A cascaded Mach-Zehnder (MZ) filter, which has no intrinsic loss, is used as the MUX. The design and fabrication of the MZ-MUX for 100 GbE are thoroughly describ...Show More

Low-Loss Cascaded Mach–Zehnder Multiplexer Integrated $25\hbox{-}{\rm Gbit}/{\rm s}\times 4\hbox{-}{\rm Lane}$ EADFB Laser Array for Future CFP4 100 GbE Transmitter

Takeshi Fujisawa;Shigeru Kanazawa;Yuta Ueda;Wataru Kobayashi;Kiyoto Takahata;Akira Ohki;Toshio Ito;Masaki Kohtoku;Hiroyuki Ishii

IEEE Journal of Quantum Electronics

Year: 2013 | Volume: 49, Issue: 12 | Journal Article |

Operating wavelength range of 25.8-Gb/s 1.3-µm DML extended to 30 nm

W. Kobayashi;K. Tsuzuki;T. Fujisawa;Y. Ohiso;Y. Ogiso;T. Ito;S. Kanazawa;T. Yamanaka;M. Kohtoku;H. Sanjoh

2013 18th OptoElectronics and Communications Conference held jointly with 2013 International Conference on Photonics in Switching (OECC/PS)

Year: 2013 | Conference Paper |

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A 30-nm operating wavelength range was realized for a 1.3-μm InGaAlAs DML with a 25.8-Gb/s push-pull driving configuration. Clear eye openings, an 8.0-dBm output power, and a 4.0-dB dynamic extinction ratio were obtained.Show More

Operating wavelength range of 25.8-Gb/s 1.3-µm DML extended to 30 nm

W. Kobayashi;K. Tsuzuki;T. Fujisawa;Y. Ohiso;Y. Ogiso;T. Ito;S. Kanazawa;T. Yamanaka;M. Kohtoku;H. Sanjoh

2013 18th OptoElectronics and Communications Conference held jointly with 2013 International Conference on Photonics in Switching (OECC/PS)

Year: 2013 | Conference Paper |

4×25-Gbit/s EADFB laser array monolithically integrated with cascaded Mach-Zhender multiplexer

T. Fujisawa;S. Kanazawa;Y. Ueda;W. Kobayashi;K. Takahata;A. Ohki;T. Itoh;M. Kohtoku;H. Ishii

2013 18th OptoElectronics and Communications Conference held jointly with 2013 International Conference on Photonics in Switching (OECC/PS)

Year: 2013 | Conference Paper |

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A 4×25-Gbit/s EADFB laser array chip monolithically integrated with a cascaded Mach-Zhender multiplexer is developed for CFP4-class 100GbE transmitters for the first time. Our compact TOSA containing this chip satisfies system requirements with semi-cooled operation.Show More

4×25-Gbit/s EADFB laser array monolithically integrated with cascaded Mach-Zhender multiplexer

T. Fujisawa;S. Kanazawa;Y. Ueda;W. Kobayashi;K. Takahata;A. Ohki;T. Itoh;M. Kohtoku;H. Ishii

2013 18th OptoElectronics and Communications Conference held jointly with 2013 International Conference on Photonics in Switching (OECC/PS)

Year: 2013 | Conference Paper |

InP-based compact reflection-type transversal filter

Y. Ueda;T. Fujisawa;K. Takahata;M. Kohtoku;H. Takahashi;H. Ishii

2013 International Conference on Indium Phosphide and Related Materials (IPRM)

Year: 2013 | Conference Paper |

Cited by: Papers (2)

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We developed a reflection-type 4x1 transversal filter (TF) on an InP substrate as a compact and low-loss wavelength multiplexer (MUX) for monolithically integrated light source arrays. The filter has a satisfactory MUX function and is very compact of about 900 Pm x 50 Pm which is one twentieth of a size of a conventional 4x1 TF. It is suitable for a MUX of a monolithically integrated light source ...Show More

InP-based compact reflection-type transversal filter

Y. Ueda;T. Fujisawa;K. Takahata;M. Kohtoku;H. Takahashi;H. Ishii

2013 International Conference on Indium Phosphide and Related Materials (IPRM)

Year: 2013 | Conference Paper |

Novel planar structure single-RF drive MZ optical modulator on InP(110) substrate

Yoshihiro Ogiso;Masakazu Arai;Eiichi Yamada;Hiromasa Tanobe;Yasuo Shibata;Masaki Kohtoku

2013 International Conference on Indium Phosphide and Related Materials (IPRM)

Year: 2013 | Conference Paper |

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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.Show More

Novel planar structure single-RF drive MZ optical modulator on InP(110) substrate

Yoshihiro Ogiso;Masakazu Arai;Eiichi Yamada;Hiromasa Tanobe;Yasuo Shibata;Masaki Kohtoku

2013 International Conference on Indium Phosphide and Related Materials (IPRM)

Year: 2013 | Conference Paper |

1.3-μm Range Metamorphic InGaAs Laser With High Characteristic Temperature for Low Power Consumption Operation

Masakazu Arai;Wataru Kobayashi;Masaki Kohtoku

IEEE Journal of Selected Topics in Quantum Electronics

Year: 2013 | Volume: 19, Issue: 4 | Journal Article |

Cited by: Papers (12)

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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 a...Show More

1.3-μm Range Metamorphic InGaAs Laser With High Characteristic Temperature for Low Power Consumption Operation

Masakazu Arai;Wataru Kobayashi;Masaki Kohtoku

IEEE Journal of Selected Topics in Quantum Electronics

Year: 2013 | Volume: 19, Issue: 4 | Journal Article |

50-Gb/s Direct Modulation of a 1.3-μm InGaAlAs-Based DFB Laser With a Ridge Waveguide Structure

Wataru Kobayashi;Toshio Ito;Takayuki Yamanaka;Takeshi Fujisawa;Yasuo Shibata;Takeshi Kurosaki;Masaki Kohtoku;Takashi Tadokoro;Hiroaki Sanjoh

IEEE Journal of Selected Topics in Quantum Electronics

Year: 2013 | Volume: 19, Issue: 4 | Journal Article |

Cited by: Papers (107)

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We demonstrate 50-Gb/s direct modulation by using 1.3-μm distributed-feedback lasers with a ridge waveguide structure. We employed InGaAlAs material for a multiple-quantum well to obtain a low damping factor K, and fabricated a ridge waveguide structure buried in benzocyclobutene to realize a structure with a low parasitic capacitance. In addition, to obtain high maximum frequency relaxation oscil...Show More

50-Gb/s Direct Modulation of a 1.3-μm InGaAlAs-Based DFB Laser With a Ridge Waveguide Structure

Wataru Kobayashi;Toshio Ito;Takayuki Yamanaka;Takeshi Fujisawa;Yasuo Shibata;Takeshi Kurosaki;Masaki Kohtoku;Takashi Tadokoro;Hiroaki Sanjoh

IEEE Journal of Selected Topics in Quantum Electronics

Year: 2013 | Volume: 19, Issue: 4 | Journal Article |

Ultracompact, 160-Gbit/s transmitter optical subassembly based on 40-Gbit/s×4 monolithically integrated light source

Takeshi Fujisawa;Shigeru Kanazawa;Kiyoto Takahata;Akira Ohki;Yuta Ueda;Ryuzo Iga;Hiroaki Sanjo;Takayuki Yamanaka;Masaki Kohtoku;Hiroyuki Ishii

2012 38th European Conference and Exhibition on Optical Communications

Year: 2012 | Conference Paper |

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The first ultracompact transmitter optical subassembly for long-distance, beyond-100-Gbit/s data communication systems based on a monolithically integrated light source is developed, and 40-Gbit/s× 4 operation with the clear eye openings up to 10-km single mode fibre transmission is demonstrated.Show More

Ultracompact, 160-Gbit/s transmitter optical subassembly based on 40-Gbit/s×4 monolithically integrated light source

Takeshi Fujisawa;Shigeru Kanazawa;Kiyoto Takahata;Akira Ohki;Yuta Ueda;Ryuzo Iga;Hiroaki Sanjo;Takayuki Yamanaka;Masaki Kohtoku;Hiroyuki Ishii

2012 38th European Conference and Exhibition on Optical Communications

Year: 2012 | Conference Paper |

1.3-μm-range InGaAs metamorphic laser for low power consumption operation

Masakazu Arai;Wataru Kobayashi;Masaki Kohtoku

ISLC 2012 International Semiconductor Laser Conference

Year: 2012 | Conference Paper |

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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.Show More

1.3-μm-range InGaAs metamorphic laser for low power consumption operation

Masakazu Arai;Wataru Kobayashi;Masaki Kohtoku

ISLC 2012 International Semiconductor Laser Conference

Year: 2012 | Conference Paper |

High-speed operation at 50 Gb/s and 60-km SMF transmission with 1.3-μm InGaAlAs-based DML

W. Kobayashi;T. Tadokoro;T. Ito;T. Fujisawa;T. Yamanaka;Y. Shibata;M. Kohtoku

ISLC 2012 International Semiconductor Laser Conference

Year: 2012 | Conference Paper |

Cited by: Papers (14)

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We demonstrate the 50-Gb/s operation of a 1.3-μm InGaAlAs directly modulated laser (DML) for the first time. Clear eye openings were achieved for a 60-km SMF transmission.Show More

High-speed operation at 50 Gb/s and 60-km SMF transmission with 1.3-μm InGaAlAs-based DML

W. Kobayashi;T. Tadokoro;T. Ito;T. Fujisawa;T. Yamanaka;Y. Shibata;M. Kohtoku

ISLC 2012 International Semiconductor Laser Conference

Year: 2012 | Conference Paper |

Demonstration of high temperature operation in 1.3-μm-range metamorphic InGaAs laser

Masakazu Arai;Yasuhiro Kondo;Shigeru Kanazawa;Takashi Tadokoro;Masaki Kohtoku

2012 Conference on Lasers and Electro-Optics (CLEO)

Year: 2012 | Conference Paper |

Cited by: Papers (1)

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A 1.3-μm-range metamorphic InGaAs laser with high characteristic temperature (T0 = 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.Show More

Demonstration of high temperature operation in 1.3-μm-range metamorphic InGaAs laser

Masakazu Arai;Yasuhiro Kondo;Shigeru Kanazawa;Takashi Tadokoro;Masaki Kohtoku

2012 Conference on Lasers and Electro-Optics (CLEO)

Year: 2012 | Conference Paper |

Polarization-Insensitive Phase Trimming of Silica-Based Waveguide Using 193- and 244-nm UV Irradiation

Yusuke Nasu;Masaki Kohtoku;Yoshinori Hibino

Journal of Lightwave Technology

Year: 2009 | Volume: 27, Issue: 20 | Journal Article |

Cited by: Papers (4) | Patents (1)

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In this paper, we describe polarization-insensitive phase trimming of silica-based waveguides with both 193- and 244-nm ultraviolet (UV) light and the trimming of both phase error and polarization dependence. A wide beam of 193-nm UV light from an ArF excimer laser is useful for phase trimming multiple waveguides. We utilize stress-release grooves to control birefringence generation while phase tr...Show More

Polarization-Insensitive Phase Trimming of Silica-Based Waveguide Using 193- and 244-nm UV Irradiation

Yusuke Nasu;Masaki Kohtoku;Yoshinori Hibino

Journal of Lightwave Technology

Year: 2009 | Volume: 27, Issue: 20 | Journal Article |

50-GHz-Spacing Athermal Mach–Zehnder Interferometer-Synchronized Arrayed-Waveguide Grating With Improved Temperature Insensitivity

Shin Kamei;Tsutomu Kitoh;Mikitaka Itoh;Tomohiro Shibata;Masaki Kohtoku

IEEE Photonics Technology Letters

Year: 2009 | Volume: 21, Issue: 17 | Journal Article |

Cited by: Papers (8) | Patents (3)

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We describe a technique designed to compensate for the residual temperature sensitivity of an athermal silica-based arrayed-waveguide grating (AWG) and its application to a 50-GHz-spacing multi/demultiplexer with a low loss and a wide passband. The device has a Mach-Zehnder interferometer (MZI)-synchronized configuration, in which the AWG and the MZI are athermalized with resin-filled grooves. The...Show More

50-GHz-Spacing Athermal Mach–Zehnder Interferometer-Synchronized Arrayed-Waveguide Grating With Improved Temperature Insensitivity

Shin Kamei;Tsutomu Kitoh;Mikitaka Itoh;Tomohiro Shibata;Masaki Kohtoku

IEEE Photonics Technology Letters

Year: 2009 | Volume: 21, Issue: 17 | Journal Article |

Waveguide Interconnection in Silica-Based Planar Lightwave Circuit Using Femtosecond Laser

Yusuke Nasu;Masaki Kohtoku;Yoshinori Hibino;Yasuyuki Inoue

Journal of Lightwave Technology

Year: 2009 | Volume: 27, Issue: 18 | Journal Article |

Cited by: Papers (8) | Patents (5)

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The interconnection of waveguides inside a silica-based planar lightwave circuit (PLC) is demonstrated both two- and three-dimensionally by using a femtosecond laser. The waveguides written with a femtosecond laser can be successfully connected to waveguides inside a PLC with low loss. Unlike previous work on the direct writing of 2-D and 3-D waveguides in bulk glass, the waveguide must be written...Show More

Waveguide Interconnection in Silica-Based Planar Lightwave Circuit Using Femtosecond Laser

Yusuke Nasu;Masaki Kohtoku;Yoshinori Hibino;Yasuyuki Inoue

Journal of Lightwave Technology

Year: 2009 | Volume: 27, Issue: 18 | Journal Article |

Ultralow Power Consumption Silica-Based PLC-VOA/Switches

Kei Watanabe;Yasuaki Hashizume;Yusuke Nasu;Masaki Kohtoku;Mikitaka Itoh;Yasuyuki Inoue

Journal of Lightwave Technology

Year: 2008 | Volume: 26, Issue: 14 | Journal Article |

Cited by: Papers (47) | Patents (1)

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We have achieved a silica-based PLC thermooptic switch with a power consumption of only 30 mW without any deterioration in the optical properties by using a tapered narrow ridge structure. To reduce the power consumption further, we propose a novel structure, the suspended narrow ridge structure, which has the advantages of both the tapered narrow ridge structure and the already reported suspended...Show More

Ultralow Power Consumption Silica-Based PLC-VOA/Switches

Kei Watanabe;Yasuaki Hashizume;Yusuke Nasu;Masaki Kohtoku;Mikitaka Itoh;Yasuyuki Inoue

Journal of Lightwave Technology

Year: 2008 | Volume: 26, Issue: 14 | Journal Article |

Port Scalable PLC-Based Wavelength Selective Switch with Low Extension Loss for Multi-Degree ROADM/WXC

Takashi Goh;Tsutomu Kitoh;Masaki Kohtoku;Motohaya Ishii;Takayuki Mizuno;Akimasa Kaneko

OFC/NFOEC 2008 - 2008 Conference on Optical Fiber Communication/National Fiber Optic Engineers Conference

Year: 2008 | Conference Paper |

Cited by: Papers (7)

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We demonstrate a port scalable PLC-based WSS with a low extension loss. The average insertion loss of the first four ports is 7.7 dB and the loss increment of a four-port extension is only 1.5 dB.Show More

Port Scalable PLC-Based Wavelength Selective Switch with Low Extension Loss for Multi-Degree ROADM/WXC

Takashi Goh;Tsutomu Kitoh;Masaki Kohtoku;Motohaya Ishii;Takayuki Mizuno;Akimasa Kaneko

OFC/NFOEC 2008 - 2008 Conference on Optical Fiber Communication/National Fiber Optic Engineers Conference

Year: 2008 | Conference Paper |

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