Minimal-post-processing 320-Gbps true random bit generation using physical white chaos

Abstract

Chaotic external-cavity semiconductor laser (ECL) is a promising entropy source for generation of high-speed physical random bits or digital keys. The rate and randomness is unfortunately limited by laser relaxation oscillation and external-cavity resonance, and is usually improved by complicated post processing. Here, we propose using a physical broadband white chaos generated by optical heterodyning of two ECLs as entropy source to construct high-speed random bit generation (RBG) with minimal post processing. The optical heterodyne chaos not only has a white spectrum without signature of relaxation oscillation and external-cavity resonance but also has a symmetric amplitude distribution. Thus, after quantization with a multi-bit analog-digital-convertor (ADC), random bits can be obtained by extracting several least significant bits (LSBs) without any other processing. In experiments, a white chaos with a 3-dB bandwidth of 16.7 GHz is generated. Its entropy rate is estimated as 16 Gbps by single-bit quantization which means a spectrum efficiency of 96%. With quantization using an 8-bit ADC, 320-Gbps physical RBG is achieved by directly extracting 4 LSBs at 80-GHz sampling rate.

Ultrafast Fully Photonic Random Bit Generator

“…Very recently, the generation rates of RBGs have shown the potential to reach a level of terabit per second (Tb/s) using similar multi-bit extraction [14][15][16][17]. We also demonstrated a 320 Gb/s random bit generation using physical white chaos [18]. However, it should be noticed that none of the ultrafast RBG proposals described above operates in real time.…”

“…Since then, chaotic LDs have been regarded as a highly promising source of randomness for ultrafast physical RBGs with much significant work having been reported over the past ten years or so [6][7][8][9][10][11][12][13][14][15][16][17][18] R from the first-order derivative between a digitized chaotic signal from a single optical feedback LD by a virtual 8-bit ADC and its time-shifted version [7]. Further, Kanter et al enhanced this rate into 300 Gb/s using high-order derivatives of the digitized chaotic signal [8].…”

Time-delay signature concealed broadband gain-coupled chaotic laser with fiber random grating induced distributed feedback

“…Broadband chaotic semiconductor lasers have been extensively studied during the past several decades for their valuable applications in secure communications [1][2][3][4][5], random number generations [6][7][8][9][10][11][12], chaotic lidar [13,14], compressive sensing [15], and time domain reflectometry [16,17]. It is well-known that semiconductor lasers exhibit a rich variety of lasing dynamics with external perturbations such as optical feedback, laser injection, current modulation, and optoelectronic feedback [18][19][20].…”

Recommendations and illustrations for the evaluation of photonic random number generators

“…Chaotic systems amplify uncertainties in initial conditions and sources of intrinsic noise [35,36]; only in the last decade has this inherent unpredictability been harnessed for random number generation in the form of chaotic lasers [18,[37][38][39][40][41][42][43][44][45]. For a review of chaotic lasers including their applications to RNGs, see ref.…”

“…Due to the increasing importance of the security of digital information and the wide variety of physical methods used to generate random numbers, a standard set of evaluation metrics for random number generation is essential. Previous works have used a variety of methods to estimate the entropy of physical sources of randomness [8][9][10][11]19,23,[25][26][27][40][41][42]44,45,50]; however, many of these techniques assume that there are no inter-sample correlations. As of this writing, there is no widely accepted technique to estimate the entropy of physical entropy sources.…”