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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)
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
Cited by: Papers (133)
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
Eight-Channel Reflection-type Transversal Filter for Compact and Easy-to-Fabricate InP-Based Optical Multiplexer
Journal of Lightwave Technology
Cited by: Papers (10)
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
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)
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
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-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
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
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)
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
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 |
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
1.3-μm Range Metamorphic InGaAs Laser With High Characteristic Temperature for Low Power Consumption Operation
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
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
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
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 |
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
Polarization-Insensitive Phase Trimming of Silica-Based Waveguide Using 193- and 244-nm UV Irradiation
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
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
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
Waveguide Interconnection in Silica-Based Planar Lightwave Circuit Using Femtosecond Laser
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
Ultralow Power Consumption Silica-Based PLC-VOA/Switches
Kei Watanabe;Yasuaki Hashizume;Yusuke Nasu;Masaki Kohtoku;Mikitaka Itoh;Yasuyuki Inoue
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
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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