Theoretical analysis of the operating state of semiconductor lasers subject to strong optical feedback

In this paper, computer simulations are employed to explore the optimum operations of semiconductor lasers (SLs) under strong optical feedback (OFB). Various material and structural parameters are used, such as the injection current I, the grating reflectivity R_g, the linewidth enhancement factor α, and aξ/V, where a is the tangential coefficient of the linear gain, ξ is the field confinement factor and V is the volume of the active region. The simulation is performed based on a new time delay model for SLs, which is applicable under strong OFB. The simulation results show that the lasing operation of SLs under strong OFB is classified into continuous wave (CW), chaos and pulsation depending on the operating conditions. The differences and characteristic features of each lasing operation in the regime of strong OFB are given.