A Poincaré approach to investigate nonlinear polarization rotation in semiconductor optical amplifiers and its application to all-optical wavelength conversion

Nonlinear polarization rotation (NPR) in semiconductor optical amplifiers (SOAs) is initially investigated. The changes of ellipticity angle of the probe light in a counter-propagation scheme are presented on the Poincaré sphere, and agree with the numerical simulations. All-optical wavelength conversions based on NPR in SOAs are realized at a bit rate of 2.5Gbit/s.