All optical clock recovery of 40 GHz quantum dash mode-locked laser to return-to-zero 160 Gb/s data stream

Optical injection in passively mode-locked (ML) semi-conductor lasers has been extensively studied for a variety of applications, the synchronization (or the so-called all-optical clock-recovery (ORC)) being among the most attractive uses for optical time division multiplexed networks. In recent studies, quantum-dash (QDash) Fabry-Perot (FP) semiconductor lasers have shown to be good candidates for implementing optical clock recovery due to their low power consumption, compact size, fast carrier dynamics, as well as broad and nearly flat gain spectrum around 1550 nm [1]. The performance of the recovered clock has usually been assessed by locking the QDash laser to optical injection of multiplexed trains of pulses. Unfortunately by multiplexing the data stream to achieve a higher bit-rate, there are still spurious spectral components at the free-running frequency of the ML laser which may affect the analysis of its locking performance.