Coherence collapse and low-frequency fluctuations in quantum-dash based lasers emitting at 1.57 mu m

Optical feedback tolerance is experimentally investigated on a 600-mu m-long quantum-dash based Fabry-Perot laser emitting at 1.57 mu m. While quantum- dashes are structurally intermediate to quantum-wells and quantum-dots, the observed behaviour is distinctly like that of a quantum-well based laser but with greater stability. Coherence collapse and low-frequency fluctuation regimes are observed and are reported here. The onset of the coherence collapse regime is experimentally determined and is found to vary from -29 dB to -21 dB external feedback level when increasing the current from twice to nine times the threshold current. (c) 2007 Optical Society of America.