Kohsuke Nishimura

Learn More
Based on nine up-to-date types of semiconductor-optical-amplifier (SOA) samples, we devised a power-consumption model of SOA-based all-optical gates as a tool to develop faster and more efficient OTDM systems for bitrates from 10 to 160 Gb/s and those over 160 Gb/s. The conventional effect of a continuous wave (cw) holding beam was included in the model.(More)
A traveling-wave electroabsorption modulator (TW-EAM) is used to realize three simultaneous functions: demultiplexing, detection, and pulse generation. These coexisting functions are achieved by utilizing microwave harmonic frequencies and independent wavelengths in the TW-EAM. When combined with a phase-locked-loop, these functions enable simultaneous(More)
We describe an optical clock recovery circuit that employs a traveling-wave electroabsorption modulator-based ring oscillator. This approach provides synchronized optical clock and the original optical data signal from the same output at separate wavelengths, eliminating additional timing adjustments for the subsequent nonlinear decision gate for(More)
An injection-locking traveling-wave electroabsorption modulator-based ring oscillator is demonstrated to perform optical clock recovery and simultaneous reshaping of 40-Gb/s optical packets. The transient response analysis and experimental results show strong injection and short loop length reduce the locking time to within 0.3 s. The recovered packet(More)
We propose a new method to characterize the conversion efficiency from the injected carriers to the excess photons in the process of all-optical gating in SOA, and investigated the efficiencies of SOAs with different structures. @2006 Optical Society of America OCIS codes: (250.5980) Semiconductor optical amplifiers; (190.5970) Semiconductor nonlinear(More)
This paper represents a comparative study among different types of existing single phase AC to DC step down converter. Their performances and outputs have been analyzed depending on their equations. Different parameters such as voltage gain, harmonic contents in input current, parameters of changing output voltage are compared among three different existing(More)
This paper proposes a new D-LDD (Double Lightly-Doped Drain) structure for InGaP-InGaAs H-MESFETs (Heterostructure-MESFET). A D-LDD H-MESFET has three kinds of low resistance layers in the drain region, while a conventional H-MESFET has two layers. This structure improves MAG accompanied by Rd reduction with minimized gate-breakdown-voltage degradation and(More)