Parallel generation of fast random bits based on optoelectronic phase-chaos systems

We model the performance of an optoelectronic phase-chaos system operating with telecom components to generate random bits. The key component of the system is differential delay, namely the system is subject to two delay times which differ in an amount much larger than the autocorrelation time. This is implemented by a delay loop and an imbalanced Mach-Zhender modulator. We show that after suitable digitalization of the chaotic signal the generated bits pass all the NIST test for randomness. We also show that the system can be extended to have several chains in parallel each with a Mach-Zhender modulator, each chain being used to produce a sequence of random bits. If the differential delays of the Mach-Zhenders differ by an amount larger than the autocorrelation time of the chaotic dynamics, the output of the different chains is uncorrelated and therefore can be used for parallel generation of statistically independent random bit-streams. In addition, we also find that a sequence constructed by interleaving the parallel bit-streams also pass all the NIST tests for randomness. Based on the least significant bits which can be included in the sequence and the number of the parallel branches which can be implemented, we show that bit rates up to Tb/s can be achieved.