Randomness-Enhanced Chaotic Source With Dual-Path Injection From a Single Master Laser

The randomness and bandwidth enhancement of chaotic signals in optically injected semiconductor lasers (SLs) with dual-path injection from a single master laser are investigated experimentally and numerically. It is shown that both the randomness and bandwidth of chaotic signals generated in a slave SL (SSL) can be enhanced significantly, especially for positive frequency detuning, by simply adding an additional injection path in the conventional master-slave configuration. The region of injection parameter space leading to wideband randomness-enhanced chaos in SSL can be greatly broadened compared to the SSL with single-path injection. This low-cost and simple configuration for wideband randomness-enhanced chaotic source is highly desirable for high-speed random number generators based on chaotic SLs.