Correlated Random Bit Generation Using Chaotic Semiconductor Lasers Under Unidirectional Optical Injection

Abstract

Correlated random bit generation is investigated using three optically injected chaotic semiconductor lasers. Based on a rate-equation model, a continuous-wave injection first perturbs a common laser into chaos. The common laser then optically injects a pair of response lasers through a public channel unidirectionally. The two response lasers of identical parameters are synchronized. Their chaotic emissions are digitized in yielding correlated random bit streams. As the scheme advantageously involves no feedback loops, the output bits contain no undesirable time-delay information artifacts. Security is ensured as the response lasers produce bits that cannot be extracted using the information in the public channel alone. Output bit streams are generated at a tunable rate of up to about 2 Gbps with randomness verified by a test suite of the National Institute of Standards and Technology. The streams are correlated with a low bit error ratio of less than 4 $\%$ , which is sensitive to parameter mismatch between the response lasers.