Nonlinear Amplitude Response of Slave Laser Induces the Chaos Pass Filtering Effect in Synchronized Semiconductor Laser Diodes

The process of synchronization in chaotic oscillators has been extensively explored using semiconductor laser based systems. One potential application of chaotic synchronization makes use of the large amplitude noise-like fluctuations that are characteristic of chaotic dynamics to mask a message. The message is then extracted from the chaotic background by comparing the slave laser output to that of the transmitted signal. The slave preferentially locks to the chaotic fluctuations and not the message via a process usually referred to as chaos pass-filtering. For the first time it will be shown that a nonlinear amplitude response is responsible for the chaos-pass filtering effect.