Cascaded wavelength converter for optical regeneration

Optical signal regeneration will be key technology for extending the total transmission distance and improvement of optical signal quality for next-generation high-speed optical transmission and optical packet networks. In addition, wavelength conversion will be advantageous for contention resolution to process each data packets with low packet loss. We have proposed and investigated the performance of a cascaded wavelength converters called a cross-gain-modulation type wavelength-converter cascaded optical regenerator (CGCOR), consisting of two-stage XGM wavelength converters based on semiconductor optical amplifiers (SOA's). By this configuration, power fluctuation in both low and high level for input light power can be suppressed, and so the improvement of the signal to noise ratio and input dynamic range can be achieved. On the other hand, a cascaded gain-saturated SOA with a XGM wavelength converter is also proposed for suppressing chirping and improving transmission characteristics. Both offset of input timing between XGM and input signal, and offset of the center wavelength of the optical bandpass filter from the input signal wavelength can result in the reduction of chirping and the error free performance in the 50km SMF transmission. The operation performance of two types of cascaded wavelength converter-type optical regenerator will be presented.