Low distortion amplification of 16 and 64QAM signals using SOA

Amplification of single channel and three Wavelength division multiplexing (WDM) channels with 16 and 64QAM modulated signals is demonstrated using an SOA with holding beam in the non-transparency wavelength to minimize phase distortion. We demonstrate an optical gain of 10 dB for single channel and for each channel in WDM operation. We also show that, the performance with holding beam can provide with minimal phase distortions a better bit-error rate value when compared to the linear regime of SOA operation for the same output power level.