Ultra-fast quantum randomness generation by accelerated phase diffusion in a pulsed laser diode

Abstract

Abstract:We demonstrate a high bit-rate quantum random number generator by interferometric detection of phase diffusion in a gain-switched DFB laser diode. Gain switching at few-GHz frequencies produces a train of bright pulses with nearly equal amplitudes and random phases. An unbalanced Mach-Zehnder interferometer is used to interfere subsequent pulses and thereby generate strong random-amplitude pulses, which are detected and digitized to produce a high-rate random bit string. Using established models of semiconductor laser field dynamics, we predict a regime of high visibility interference and nearly complete vacuum-fluctuation-induced phase diffusion between pulses. These are confirmed by measurement of pulse power statistics at the output of the interferometer. Using a 5.825 GHz excitation rate and 14-bit digitization, we observe 43 Gbps quantum randomness generation.

Random Number Generation with Cosmic Photons

“…The main results are summarized in Table I. First, we notice that the photon counting signal rates exceed 10 6 s −1 (which is within the linear operation mode of the SPAD in use) for CRSS with lower magnitude, demonstrating that this method is as efficient as laser-based RNGs in generating random numbers [19][20][21][22][23][24][25]. Second, despite the dramatic fluctuation of signal rates (shown by signal ranges in Table I ), the true signal rate (with background subtracted) scales with magnitude as expected, as indicated in Fig.…”

Generation of Fresh and Pure Random Numbers for Loophole-Free Bell Tests

“…To be secure, they must close two spacetime loopholes: no basis choice may influence a distant particle (locality loophole), and the entanglement generation must not influence the basis choices (freedom-ofchoice loophole). Current efforts [6,7,[12][13][14] to simultaneously close the detection [4,6,7], locality [3], and freedom-of-choice (FoC) [5,8] loopholes require random number generators (RNGs) with an unprecedented combination of speed, unpredictability, and confidence [15][16][17].Here we combine ultrafast RNG by accelerated laser phase diffusion [18][19][20] with real-time randomness extraction and metrological randomness assurances [21] to produce a RNGs suitable for loophole-free Bell tests. Because the laser phase diffusion is driven by effects, including spontaneous emission, that are unpredictable both in quantum theory and in an important class of stochastic hidden variable theories, the source can be used to address the "freedom-of-choice" loophole [22].…”

Random numbers from vacuum fluctuations

“…Since the reflection/transmission of the photon is intrinsically random due to the quantum nature of the process, the unpredictability of the generated numbers is ensured 14 . Other implementations of QRNGs measure the amplified spontaneous emission 15 , the vacuum fluctuations of the electromagnetic field [16][17][18] , or the intensity 19,20 and phase noise of different light sources [21][22][23][24][25] .…”