Unbiased All-Optical Random-Number Generator

TL;DR

This paper introduces a purely optical, unbiased random number generator based on an optical parametric oscillator, producing high-quality random bits without bias, memory effects, or the need for post-processing, suitable for cryptographic applications.

Contribution

It presents a novel all-optical randomness generator that leverages vacuum fluctuations and bi-stable states, eliminating detector noise influence and post-processing requirements.

Findings

Produces unbiased random bits with high entropy

Passes all standard randomness tests

No post-processing needed for randomness quality

Abstract

The generation of random bits is of enormous importance in modern information science. Cryptographic security is based on random numbers which require a physical process for their generation. This is commonly performed by hardware random number generators. These exhibit often a number of problems, namely experimental bias, memory in the system, and other technical subtleties, which reduce the reliability in the entropy estimation. Further, the generated outcome has to be post-processed to "iron out" such spurious effects. Here, we present a purely optical randomness generator, based on the bi-stable output of an optical parametric oscillator. Detector noise plays no role and no further post-processing is required. Upon entering the bi-stable regime, initially the resulting output phase depends on vacuum fluctuations. Later, the phase is rigidly locked and can be well determined versus a pulse train, which is derived from the pump laser. This delivers an ambiguity-free output, which is reliably detected and associated with a binary outcome. The resulting random bit stream resembles a perfect coin toss and passes all relevant randomness measures. The random nature of the generated binary outcome is furthermore confirmed by an analysis of resulting conditional entropies.