Polarization properties of four-wave mixing in strained semiconductor optical amplifiers

We present a theoretical and experimental study of the polarization properties of the four-wave mixing susceptibility of highly-strained multiquantum-well optical amplifiers and show how the intensity and polarization of the four-wave mixing signal depend on the polarization of the input waves. We demonstrate the validity of our model by generating a wavelength-converted signal having a polarization orthogonal to that of the pump wave at the output of the amplifier. In addition, we discuss the possibility of making the conversion efficiency independent of the input signal polarization by proper selection of the pump polarization.