WIDELY TUNABLE 4-WAVE-MIXING IN SEMICONDUCTOR OPTICAL AMPLIFIERS WITHCONSTANT CONVERSION EFFICIENCY

The conversion efficiency and output signal-to-noise ratio (SNR) of si ngle-pump four-wave mixing (FWM) in semiconductor optical amplifiers ( SOA's) is strongly dependent on frequency shift. We examine a scheme f or FWM in SOA's that uses two orthogonally polarized pumps. We compare experimentally and theoretically the conversion efficiency and SNR of the orthogonal-pump scheme,vith single-pump FWM, The orthogonal-pump scheme has nearly constant conversion efficiency and SNR over the 4.5- THz range of frequency shifts measured. Experimental and theoretical r esults for the conversion efficiency and SNR of the orthogonal-pump sc heme agree to within 3.5 dB.