All-Optical NRZ-OOK to BPSK Format Conversion in an SOA-Based Nonlinear Polarization Switch

All-optical format conversion from nonreturn-to-zero on-off keying to binary phase-shift keying is demonstrated in a semiconductor optical amplifier-based nonlinear polarization switch. This conversion is realized by cross-phase modulation effect for phase encoding and nonlinear polarization rotation effect for amplitude equalization. In the experiment, error-free operation at 10 Gb/s is achieved with a receiver sensitivity penalty of 1.3 dB after single-ended detection.