title: Ultra-fast quantum randomness generation by accelerated phase diffusion in a pulsed laser diode.
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.
authors: C
authors: C
authors: Abellán
authors: W
authors: W
authors: Amaya
authors: M
authors: M
authors: Jofre
authors: M
authors: M
authors: Curty
authors: A
authors: A
authors: Acín
authors: J
authors: J
authors: Capmany
authors: V
authors: V
authors: Pruneri
authors: M W
authors: MW
authors: Mitchell