Optical-feedback-induced chaos and its control in semiconductor lasers

In this paper we describe some of the effects of external optical feedback (OFB) on semiconductor lasers by simulation of the stochastic rate equations. Particular attention is paid to the laser's transition to optical chaos. In addition, we describe three techniques for avoiding this chaotic regime. The technique of high frequency injection, used in optical recording, can delay the onset of chaos till very high values of OFB. Experimental results are given and are in excellent agreement with the theory. A second technique called occasional proportional feedback can be used with some success to stabilize the chaotic output of semiconductor lasers. The final technique for controlling chaos consists of the optimization of various system and laser parameters so that the laser is least susceptible to OFB.