Wavelength Tunability of All-Optical Clock-Recovery Based on Quantum-Dash Mode-Locked Laser Diode Under Injection of a 40-Gb/s NRZ Data Stream

Wavelength tunability of an all-optical clock recovery operation based on a quantum-dash mode-locked Fabry-Pérot laser diode is experimentally investigated. Synchronization of the device to the injection of 40-Gb/s nonreturn-to-zero (NRZ) incoming data is assessed by analyzing both the carrier-to-noise ratio and the linewidth of the 40-GHz beat-tones measured at the mode-locked laser output. Under optical injection, beat-tone linewidths below 10 Hz are measured. Recovered clock pulses featuring a width of 1.6 ps are obtained irrespective of the wavelength detuning between the laser spectra and the optical carrier of the incoming data stream.