Parallel random bit generation based on a multi-longitudinal-mode self-chaotic semiconductor microcavity laser

Using parallel chaotic sources for simultaneous multi-channel random bit generation is an effective approach to increase the generation rate. We propose utilizing multiple longitudinal modes of a self-chaotic semiconductor microcavity laser as parallel chaotic sources to generate random bits, and found that retaining the least significant bits (LSBs)—a post-processing step typically required for random bit generation from chaotic semiconductor lasers—can dramatically reduce the correlation between different longitudinal modes. As long as no significant correlation remains between the longitudinal modes after retaining the LSBs, they can be used as parallel chaotic sources for random bit generation. In the case of 8-bit raw data, the correlation is generally eliminated when 5 or fewer LSBs are retained. Furthermore, without additional post-processing beyond LSB retention, the resulting random bit stream can typically retain up to 5 LSBs while still passing the statistical tests specified in the National Institute of Standards and Technology Special Publication 800-22. This implies that the correlation requirements for parallel chaotic sources can be significantly relaxed. We collected signals generated by three longitudinal modes of a self-chaotic laser at a sampling rate of 10 GSa/s, achieving a random bit generation rate of 130 Gb/s. The use of a solitary multi-longitudinal-mode self-chaotic microcavity laser not only simplifies the system but also further enhances the rate of random bit generation.