How Time-Distributed Feedback Impacts the Laser Dynamics?

Subjecting semiconductor lasers to time-distributed optical feedback has been considered in the recent years to improve the quality of the generated optical chaos, for instance by reducing the time-delay signature. The distribution of feedback in time is obtained by fiber Bragg gratings (FBGs), which have a well-known band-pass-like reflectivity spectrum with a main lobe surrounded by several side lobes. Due to its specific shape, it effectively suppresses the coherence collapse of the laser and can keep the laser in period-one operation even under relatively strong feedback [1]. The time-distributed feedback from a detuned FBG has been shown to effectively suppress the undesirable time-delay signature (TDS) due to dispersion at frequencies near the edge of the main lobe of the FBG [2]. Moreover, to vary the parameters of the feedback chirped FBGs have been employed [3], as well as the effects of the FBG feedback phase have been studied [4], however, the fundamental impact that the distribution of the feedback in time has on the laser dynamics has not been investigated yet.