Reduction of semiconductor optical amplifier induced distortion and crosstalk in a 1.3-μm WDM transport system

A four-wavelength 256-QAM wavelength-division-multiplexing (WDM) semiconductor-optical-amplifier (SOA) amplified transport system using a light injection technique over an 80-km single-mode fiber (SMF) link is proposed and demonstrated. SOA-induced distortion and crosstalk can be reduced by employing the light injection technique, thus system performance can be further improved. Our proposed WDM transport system can transmit 252 256 quadrature amplitude modulation digital channels with a bit-error rate <10/sup -9/. It can be concluded that our light injection technique is a very useful approach for reducing distortion and crosstalk in an SOA amplified WDM transport system.