Kosuke Nishimura

Novel scheme for reducing the pattern effect in 40 Gbps SOA based all-optical switch utilizing transparent CW assist light

We have successfully confirmed the reduction of the pattern effect in semiconductor optical amplifier (SOA)-based all-optical switches at 40 Gb/s operation, utilizing the transparent CW assist light which clamped the gain profile of the SOA. Error-free operation without an error floor was obtained with a power penalty of 1 dB compared with the input data stream. The receiver sensitivity improvement of 2.3 dB was confirmed at BER=10/sup -9/. The scheme for the reduction of the pattern effect is an attractive method for high-speed operation because the required signal powers can be small.

Patterning effect at 40 Gbit/s of wavelength converter utilizing cross-phase modulation in InGaAsP/InP electroabsorption modulator

Cross-absorption and cross-phase modulation in an InGaAsP/InP electroabsorption modulator (EAM) were experimentally analyzed. The patterning effect of the EAM-based delayed-interferometric wavelength converter was studied by numerical simulation based on the experimental results.

Control pulse propagation direction dependence of cross-gain and cross-phase modulation induced in semiconductor optical amplifier

Cross-gain and cross-phase modulation induced in semiconductor optical amplifier depending on the propagation direction of control pulse was investigated numerically and experimentally.

Device length dependency of cross gain modulation and gain recovery time in semiconductor optical amplifier

The cross gain modulation and its recovery time in the SOAs with the various lengths were experimentally investigated. It was found that these values strongly depended on the device length.

Optical 3R regeneration with single InGaAsP/InP electroabsorption modulator

A new optical 3R regeneration technique, which is referred to as RF-XAM 3R regeneration, that requires only one electroabsorption modulator (EAM) for both clock recovery and gating was proposed for the first time. The idea was experimentally verified at 20 Gbit/s and we have confirmed that the RF-XAM 3R regenerator possesses retiming function. The simple configuration of our proposed scheme is expected to contribute not only to reduction in size and power consumption, but also high stability and easy tunability.

Experimental demonstration of Gbit/s wavelength conversion based on cross gain modulation in cascaded semiconductor optical amplifiers

We experimentally demonstrated 10 Gbit/s XGM based wavelength conversion by using cascaded SOAs adapting intentional loss in-between. The input power dynamic range toward lower level side was increased from 0.8 dB to 1.8 dB by cascading SOAs with the intermediate loss.