OPTICAL SPECTRAL INVERSION WITHOUT FREQUENCY-SHIFT BY 4-WAVE-MIXING USING 2 PUMPS WITH ORTHOGONAL POLARIZATION

We propose a method to obtain spectral inversion of a signal without s hifting its frequency, We use four-wave mixing (FWM) in a semiconducto r optical amplifier (SOA) with two pumps of orthogonal polarization, A conjugate field is generated with a polarization orthogonal to that o f the incoming signal and is selected at the amplifier output by a pol arizer, Using a commercially available pig-tailed SOA of 1.5-mm length , we obtain after the polarizer 21.5 dB of intensity ratio between con jugate and amplified incoming signal.