We demonstrate the generation of a supercontinuum from modulation instability and Raman self-frequency shift in a distributed feedback random Raman fiber laser. This laser has the potential for random number generation at Tbps speeds.
A simple novel method for random number generation is presented, based on a random Raman fiber laser. This laser is built in a half-open cavity scheme, closed on one side by a narrow-linewidth 100 mm fiber Bragg grating. The interaction between the randomly excited lasing modes of this laser, in addition to nonlinear effects such as modulation instability, allow the generation of random bits at rates of up to 540 Gbps with minimal post processing. Evaluation of the resulting bit streams' randomness by the NIST statistical test suite highlights the importance of evaluating the physical entropy content, as bit sequences generated by this random laser pass all the statistical tests with a significance level of 0.01, despite being generated at more than twice the theoretical entropy generation speed.
Here we propose a novel complementary concept of all-optical technique that might dramatically increase the generation rate of random bits by using simultaneously multiple spectral channels with uncorrelated signals somewhat similar to use of wave-division-multiplexing in communications. We propose to exploit the intrinsic nonlinear dynamics of extreme spectral broadening and supercontinuum (SC) generation in optical fibre, a process known to be often associated with non-deterministic fluctuations [2]. In this paper, we report proof-of concept results indicating that the fluctuations in highly nonlinear fibre SC generation can potentially be used for random number generation.
A bidirectional pumping Brillouin random fiber laser based on a non-uniform fiber is proposed and demonstrated for truly random number generation with enhanced bit rate. Numerical simulation indicates that, thanks to the unique distributed Brillouin gain profile along the non-uniform fiber, random lasing oscillation within a broadband Brillouin gain can be established by the mutual effect of Brillouin scattering and enhanced Rayleigh scattering, providing physical entropy source for truly random number generation. The poof-of-concept experiments demonstrate a truly random number with a bit rate of 71 Mbps, which significantly breaks through the limitation of the intrinsic Brillouin bandwidth (~10 MHz) in communication fibers.
We demonstrate for the first time, to the best of our knowledge, a high-speed physical random bit generator at gigabits/second without the time-delay signature based on chaotic power fluctuations of a random fiber laser. The random fiber laser is configured using a ring structure with semiconductor optical amplifiers as the optical gain and a fiber random grating as the random feedback medium. The long-length ring cavity provides a large number of densely spaced cavity modes that co-exist within the gain bandwidth tailored by the optical filter. Unlike fixed cavity modes in conventional fiber ring lasers, these modes are less phase-correlated due to the random distributed feedback from the fiber random grating fabricated by a plane-by-plane inscription technique without phase control, leading to intensified lasing output fluctuations with high-dimensional chaotic dynamic natures without specific cavity features, when the random fiber laser is operated slightly above the lasing threshold. Random bit generation at a bit rate up to ∼1.6 Gbps is achieved with verified randomness through standard tests. Different from the previously reported schemes requiring offline post-processing procedures, this physical random number generator can function in real time, offering high-quality randomness and security assurance for pertinent applications.
Fast and reliable random number generation (RNG) is a key requirement for, e.g., secure telecommunication or quantum simulations. This has driven the development of physical random number generators to replace deterministic, pseudo-random number generators. Semiconductor lasers exhibiting chaotic dynamics induced for example by optical feedback [1] can provide up to 1 Tbit/s, but their speed is ultimately limited by the time scales of the laser dynamics. Parallel RNG via spatial or spectral multiplexing can further increase the speed but previous demonstrations were limited by low intrinsic speed or a small number of channels.