Tolerance to Optical Feedback of 10 GBPs Quantum-Dash Based Lasers Emitting at 1.55 μm

Tolerance to optical feedback is investigated on quantum-dash based lasers emitting at 1.55 μm on both static and dynamic regimes. The onset of coherence collapse regime is experimentally determined using three criteria: optical spectrum broadening, relative intensity noise increase and bit error rate degradation. In spite of a relatively high linewidth enhancement factor (α_H˜4.5), a -32 dB onset of coherence collapse corresponding to -24 dB maximum optical return loss tolerance from the system was achieved at 10 Gbps rate.