Enhanced Two-Channel Optical Chaotic Communication Using Isochronous Synchronization

The concealment of time delay signature of chaotic signals, which are generated by a slave laser (SL) with dual-chaotic optical injections (DCOI) from two external-cavity master lasers (MLs), is investigated numerically. Under certain circumstances, the SL can generate complex and wideband chaotic signals by adopting DCOI. Two scenarios of time delay concealment are identified by adjusting the injection strength and frequency detuning. Both the time delays of MLs can be masked simultaneously or only one of them can be eliminated. It is shown that enhanced two-channel optical chaotic communication using isochronous synchronization is successfully achieved, when twin semiconductor lasers are driven by the time delay eliminated chaotic signal. Moreover, this two-channel approach can be extended to any communication systems using complex chaotic signals generated by a small network of coupled semiconductor lasers. Our results are also valuable for understanding the characteristics of time delay signatures in laser networks and chaos-based multiplexing systems.