Chaos Synchronization and Communication in Mutually Coupled Semiconductor Lasers Driven by a Third Laser

We numerically investigate the chaos synchronization and message transmission between two mutual coupling semiconductor lasers (MCSLs) subject to identical unidirectional injections (UIs) from an external cavity semiconductor laser (ECSL). The synchronization between the MCSLs is realized through injection locking in conjunction with symmetric operation. The simulation results show that stable isochronal synchronization between the MCSLs can be achieved under proper driving injections. This type of synchronization is robust to parameter mismatch up to tens of percentage and frequency de-tuning of several tens of gigahertz, which is much better than those of the MCSLs systems with self-feedback. Moreover, the investigations on the mutual chaos pass filtering effects and the message transmission indicate that the isochronal synchronization allows mutual message exchange with a bit rate higher than 10 Gb/s, when the chaos modulation technology is adopted. In addition, the MCSLs can synchronize with the ECSL for proper UI and MC, which provides an opportunity for array chaos synchronization and chaos communication networks. Finally, leader/laggard synchronization can also be achieved in the proposed system.