Influence of nonlinear gain in the operations of semiconductor laser with optical feedback

Effects of nonlinear gain on the operations and route-to-chaos of semiconductor laser subject to optical feedback are investigated. The simulation is performed based on numerical solution of an improved time delay model, which is applicable under any arbitrary strength of feedback. The route-to-chaos and the operations of laser are classified in terms of the bifurcation diagrams of the photon number at each feedback rate. The simulation results show that, inclusion of nonlinear gain in the rate equations cause significant changes in the route-to-chaos and operations of the laser. The value of the feedback rate at which the transition from CW to periodic oscillation or chaos state occur increase, as the intensity of the nonlinear gain is increased. Under strong feedback and by increasing the values of the nonlinear gain the operations of the laser change from chaos operations to periodic oscillations or CW operation depending on feedback strength.