US 11,709,657 B2
High bandwidth quantum random number generator
Taofiq Paraiso, Cambridge (GB); Davide Marangon, Cambridge (GB); Thomas Roger, Cambridge (GB); Zhiliang Yuan, Cambridge (GB); and Andrew Shields, Cambridge (GB)
Assigned to Kabushiki Kaisha Toshiba, Minato-ku (JP)
Filed by Kabushiki Kaisha Toshiba, Minato-ku (JP)
Filed on Feb. 28, 2020, as Appl. No. 16/804,286.
Claims priority of application No. 1903675 (GB), filed on Mar. 18, 2019.
Prior Publication US 2020/0301669 A1, Sep. 24, 2020
Int. Cl. G06F 7/58 (2006.01); G06N 10/00 (2022.01); G01J 9/02 (2006.01); H01S 5/042 (2006.01); H01S 5/40 (2006.01); H01S 5/12 (2021.01); H04L 9/08 (2006.01)
CPC G06F 7/588 (2013.01) [G01J 9/02 (2013.01); G06N 10/00 (2019.01); H01S 5/0428 (2013.01); H01S 5/12 (2013.01); H01S 5/4012 (2013.01); H04L 9/0852 (2013.01); H04L 9/0869 (2013.01)] 19 Claims
OG exemplary drawing
 
1. An optical device for a quantum random number generator comprising:
a source of phase randomised pulses of light, the source of phase randomised pulses of light further comprising
a plurality of gain-switched lasers, each gain-switched laser having an output, and each gain-switched laser being configured to emit a stream of pulses such that the phase of each pulse in the stream of pulses is randomised, and
an optical pulse combiner, the optical pulse combiner being configured to receive streams of pulses from the output of each gain-switched laser, combine the streams of pulses with one another into an interleaved stream of pulses and direct the interleaved stream of pulses into at least one output of the optical pulse combiner, the at least one output of the optical pulse combiner being the output of the source of phase randomised pulses of light,
wherein the source of phase randomised pulses of light is configured such that the streams of pulses of light emitted by the plurality of gain-switched lasers are temporally offset relative to one another;
a phase measurement element, the phase measurement element being configured to receive the interleaved stream of pulses from the output of the source of phase randomised pulses of light from the optical pulse combiner; and
an optical detector, the optical detector being optically coupled to the phase measurement element,
wherein the phase measurement element is a time delay interferometer and is configured to direct light from the at least one output of the source of phase randomised pulses towards two arms, at least one arm comprising an interferometer delay,
wherein light from the two arms are interfered with each other and directed to the output of the phase measurement element, and
wherein the interferometer delay is set to allow the interferometer to interfere two pulses from the interleaved stream of pulses from the output of the source of phase randomised pulses of light.