Erasure of time-delay signatures in the output of an opto-electronic feedback laser with modulated delays and chaos synchronisation

By studying the autocorrelation function of the opto-electronic feedback semiconductor laser output the authors establish that the signatures of time delays can be erased in systems incorporating modulated feedback time delays. This property is of importance for the suitability of such laser systems for secure chaos-based communication systems. The authors also make the first report on chaos synchronisation in both uni-directionally and bi-directionally coupled multiple time-delay chaotic semiconductor lasers with modulated opto-electronic feedbacks.