Birefringence in semiconductor optical amplifiers and its application to all optical noninverted wavelength conversion

We present experimental results on signal-induced birefringence effect in semiconductor optical amplifiers. The polarization rotation of a continuous-wave (CW) probe beam and the variation of the gain difference between the TE and TM mode with input signal power have been observed. Using the signal-induced birefringence, the noninverted wavelength conversion at 10 Gb/s nonreturn-to-zero (NRZ) data with high extinction ratio (> 13 dB) and negative chirp was obtained. Zero power penalty transmission over 110 km conventional single mode fiber (SMF) without any dispersion compensation measure after the conversion was achieved.