A new approach to modelling the coherence of optical feedback in dynamical semiconductor laser systems

It is well known that optical feedback in a laser system, such as the semiconductor laser-based one shown schematically in fig.1, can either stabilise or destabilise its output power and spectral characteristics. Semiconductor lasers have a level of sensitivity to optical feedback that is far greater than most lasers [1-3]. The current interest in using semiconductor laser with optical feedback systems, including versions implemented as integrated devices, in, for example, random number generation, reservoir computing and secure communications [1-3], sustains vigorous research activity in the field. The high, and increasing, potential for making strong connections between the predictions of increasingly sophisticated theoretical models of these complex systems and experimental measurements also reinforces the sustained activity in the field.