The present invention provides a wavelength converter with wideband four-wave-mixing,
which includes a laser diode, an optical modulator, a first and a second polarization
controllers, a first, a second and a third tunable lasers, an optical coupler,
a semiconductor optical amplifier (SOA) and a multiplexer. The present invention
utilizes an assist beam that can improve the recovery rate and saturation power
of the SOA. While the SOA is operated at a bias current close to the transparent
condition for the assist beam, it does not influence the gain of the SOA wavelength converter.
