Dual-channel physical random bits generation by a master-slave vertical-cavity surface-emitting lasers chaotic system

Taking the chaotic output from a master-slave framework chaotic system as chaotic entropy resource, we propose a scheme for acquiring dual-channel high-speed physical random bits (PRBs). For such a scheme, a vertical-cavity surface-emitting laser (VCSEL) under polarization-preserved optical feedback from a fiber Bragg grating is utilized as the master VCSEL (M-VCSEL). Under suitable operating parameters, both X and Y polarization components (X-PC and Y-PC) of the M-VCSEL can output chaotic signals with comparable power and weak time-delay signatures. The chaotic outputs from the X-PC and Y-PC of the M-VCSEL are divided into two parts, and then injected into the corresponding polarized component of another VCSEL (named as slave VCSEL, S-VCSEL) after undergoing different flight-time, and such an injection method is named as dual-path polarization-preserved optical injection (DP-PPOI). The X-PC and Y-PC in the S-VCSEL under DP-PPOI can simultaneously output chaotic signals with enhanced bandwidth, which are quantified by 8-bit analog-to-digital converters and taken as the entropy sources for generating dual-channel bit sequence after adopting m least significant bits (m-LSBs) extraction and logical exclusive-OR post-processing. Finally, the randomness of the bit sequences generated under optimized parameters is tested by NIST SP 800-22 statistical test suite. The results demonstrate that dual-channel random bits at rate of 500 Gbit s−1 can be obtained, and the rate of random bits can be further increased to 1 Tbit s−1 through adopting cross-merging method.