Polarization-Insensitive All-Optical 160-Gb/s Clock Recovery With a Monolithic Passively Mode-Locked Laser Diode in Polarization-Diversity Configuration

A new polarization-diversity configuration was proposed and demonstrated for all-optical, polarization-insensitive clock recovery using a mode-locked laser diode. The system was easily achieved only by adding an adequate length of polarization-maintaining fiber to a conventional polarization-dependent clock recovery setup. Stable clock recovery with small polarization dependence less than 0.5 dB was successfully achieved remaining at low timing jitter of less than 0.17 ps with no significant changes in the pulse characteristics. We also succeeded in the stable clock recovery for the input of polarization-scrambled data signals.