Direct generation of all-optical random numbers from optical pulse amplitude chaos

Abstract

We propose and theoretically demonstrate an all-optical method for directly generating all-optical random numbers from pulse amplitude chaos produced by a mode-locked fiber ring laser. Under an appropriate pump intensity, the mode-locked laser can experience a quasi-periodic route to chaos. Such a chaos consists of a stream of pulses with a fixed repetition frequency but random intensities. In this method, we do not require sampling procedure and external triggered clocks but directly quantize the chaotic pulses stream into random number sequence via an all-optical flip-flop. Moreover, our simulation results show that the pulse amplitude chaos has no periodicity and possesses a highly symmetric distribution of amplitude. Thus, in theory, the obtained random number sequence without post-processing has a high-quality randomness verified by industry-standard statistical tests.

Fast and Tunable All-Optical Physical Random Number Generator Based on Direct Quantization of Chaotic Self-Pulsations in Two-Section Semiconductor Lasers

“…We quantize the generated chaotic self-pulsations with the same method as that in [28] and [34], which is implemented using a DFB laser functioning as an AOFF. Through injecting a CW light into such a laser diode, a bistability phenomenon can appear due to the spatial hole burning effect, which is the base of AOFF operation.…”

“…1. Herein, it must be pointed out that only when the injected pulse power is higher above a certain threshold determined by the hysteresis curve width (expressed as ΔP = P th2 − P th1 in [28] and [34]), the switch between the two output states happens. In addition, it should be noted that this kind of AOFF is proposed and demonstrated from both experiment and simulation by Huybrechts et al [40]- [42].…”

“…On the basis of the aforementioned phenomena, the quantizing to the chaotic self-pulsations can be achieved numerically. For more details, see [28] or [34]. Fig.…”

“…The reason why the threshold bias for high-quality randomness is only allowed in such a small range is that the AOFF threshold (i.e., the width of the bistability range, ΔP = P th2 − P th1 in [28] and [34]) at the quantizing step in our TRNG (see Section II-B) is located at a low level, only 0.1 mW, so that the chaotic pulse streams have to be attenuated to make their mean pulse power in accordance with the threshold. In fact, the AOFF threshold, ΔP = P th2 − P th1 , has a large room to be increased.…”

“…Recently, we have proposed and demonstrated a simple method of a TRNG using discrete-time stochastic systems as physical entropy sources [34]. In this method, a discrete pulse amplitude chaos from a fiber ring laser passively mode locked by nonlinear polarization rotation is directly quantized into high-quality random number sequences in the absence of sampling and postprocessing procedures.…”