Birefringence effects in an InGaAsP/InP tensile-strained bulk semiconductor optical amplifier (SOA) are demonstrated. All-optical wavelength conversions based on birefringence induced polarization rotation in SOAs are investigated. It is shown that a bit error rate of <10-9 can be achieved and an extinction of >9dB can be obtained at a bit rate of 2.488Gbit/s with a 2 31-1 non-return-to-zero (NRZ) pseudorandom bit sequence (PRBS).