2.8Gbps Random Bit Generation Based On Bandwidth-Enhanced Chaotic Laser

Chaotic laser with good randomness and wide bandwidth characteristic can be generated easily by semiconductor laser under appropriate external disturbance. Based on its randomness, chaotic laser can be employed as physical entropy source to extract random bit sequences. Benefit from its wide bandwidth characteristic, chaos-based random number generator can greatly improve the bit rate of random bit sequences. Furthermore, it is difficult to accurately measure the initial conditions, and the evolution is very sensitive to the initial conditions. So, it is almost impossible to backstepping the chaotic evolutional law according to the known chaotic time series. That is to say, the random number generator based on chaotic laser can produce very secure random sequences. So chaos-based random number generator can generate high speed and good randomness random bit sequences, which has very broad applied prospect in modern science & technology and our lives.Focusing on the high-speed random number generator that based on broadband chaotic laser, the main works are summarized as follows:1. According to our team's previous research, we experimentally demonstrate the generation of ultra-broad bandwidth chaotic laser by an optical feedback semiconductor laser with continuous-wave optical injection. And it serves as physical source in our 2.87Gbps random bit generator.2. Based on the noise-like characteristic of the ultra-broad bandwidth chaotic laser that generated by optical feedback semiconductor laser with external optical injection, we introduce the extraction of 2.87Gbps high-speed random number from ultra-broad bandwidth chaotic time series.3. Combing the broadband detectors, high-speed comparators, D flip-flops and multi-frequency clock generator, we design the high-speed analog to digital conversion circuit to exact high-speed random sequences from chaotic time series. Finally,2.87Gbps random bit sequences are realized.4. The randomness of random bit sequences is improved effectively using an exclusive OR operation to combine the two binary sequences that generated by high-speed analog to digital conversion circuit.5. We adopt NIST randomness test suite to test the obtained random bit sequences. The results indicate that multi-speed random bit sequences after exclusive OR operation all can pass the NIST test and have enough randomness.