Quantum random number generation based on vacuum field fluctuations

[ANGLÈS] Random numbers are extensively used in a broad range of applications. Nevertheless, there are two main markets from a commercial point of view: (i) secure communications and (ii) stochastic simulation. According to the generation rate and quality of the random numbers required, different approaches have been used so far, most of them based on pseudo-random number generation. However, these type of generators have already started showing weakness both in the quality and the generation rate. Thus, novel techniques based on physical processes are being studied and used nowadays. In this work an ultra-fast random number generator based on quantum vacuum fluctuations is demonstrated. Not only assuring the intrinsic randomness of quantum mechanics, but also being compliant with the speed needs of current applications. Employing a DFB laser diode in gain-switched mode and interferometry, the random phase generated in spontaneous emission events is translated into random amplitudes easily measurable using off-the-shelf components, i.e. measuring a quantum phenomena in a macroscopic way. Thus, using established models of semiconductor lasers, we predict a regime of high-visibility interference and nearly complete vacuum-fluctuation-induced phase diffusion between pulses. These predictions are confirmed by measurement of pulse amplitude statistics at the exit of the interferometer.[ANGLÈS] Random numbers are extensively used in a broad range of applications. Nevertheless, there are two main markets from a commercial point of view: (i) secure communications and (ii) stochastic simulation. According to the generation rate and quality of the random numbers required, different approaches have been used so far, most of them based on pseudo-random number generation. However, these type of generators have already started showing weakness both in the quality and the generation rate. Thus, novel techniques based on physical processes are being studied and used nowadays. In this work an ultra-fast random number generator based on quantum vacuum fluctuations is demonstrated. Not only assuring the intrinsic randomness of quantum mechanics, but also being compliant with the speed needs of current applications. Employing a DFB laser diode in gain-switched mode and interferometry, the random phase generated in spontaneous emission events is translated into random amplitudes easily measurable using off-the-shelf components, i.e. measuring a quantum phenomena in a macroscopic way. Thus, using established models of semiconductor lasers, we predict a regime of high-visibility interference and nearly complete vacuum-fluctuation-induced phase diffusion between pulses. These predictions are confirmed by measurement of pulse amplitude statistics at the exit of the interferometer.

Sep 9, 20130 citations

Fast quantum randomness generation from vacuum fluctuation induced phase diffusion between pulses of laser diode

Р. П. Ермаков, V. L. Kurochkin, Violetta Sharoglazova +3 more

In this paper, the prototype of quantum random number generator (QRNG) which is shown by extracting ran- domness from vacuum fluctuation of the electromagnetic field inside the laser cavity. A distributed feedback (DFB) laser diode (LD) is directly modulated to produce short optical pulses. The laser is operated far above and far below the threshold resulting in field of pulse which has a true random phase. The efficient conversion of vacuum fluctuations to random sequence of power of optical pulses is made by homemade Michelson interferom- eter. A proposed device has proven to have far more superior interferometric visibility coupled with high power making it also a cost-effective PIN diode detector as compared to QRNGs based on phase fluctuation modu- lated by constant current. As a result a proposed device is highly integrated using only commercially available components. Due to appropriate realization of our device, we have a good quality of raw random bits that have passed all tests without postprocessing. So the postprocessing doesn't significantly decrease the speed of output random bits. In fact, we have successfully demonstrated a prototype of high speed QRNG at a generation rate of over 1 Gbps.In this paper, the prototype of quantum random number generator (QRNG) which is shown by extracting ran- domness from vacuum fluctuation of the electromagnetic field inside the laser cavity. A distributed feedback (DFB) laser diode (LD) is directly modulated to produce short optical pulses. The laser is operated far above and far below the threshold resulting in field of pulse which has a true random phase. The efficient conversion of vacuum fluctuations to random sequence of power of optical pulses is made by homemade Michelson interferom- eter. A proposed device has proven to have far more superior interferometric visibility coupled with high power making it also a cost-effective PIN diode detector as compared to QRNGs based on phase fluctuation modu- lated by constant current. As a result a proposed device is highly integrated using only commercially available components. Due to appropriate realization of our device, we have a good quality of raw random bits that have passed all tests without postprocessing. So the postprocessing doesn't significantly decrease the speed of output random bits. In fact, we have successfully demonstrated a prototype of high speed QRNG at a generation rate of over 1 Gbps.

International Conference on Micro- and Nano-Electronics (ICMNE)Mar 15, 20190 citations

Practical quantum random number generator based on sampling vacuum fluctuations

Qiang Zhou, Raju Valivarthi, Caleb John +1 more

Random number generation is an enabling technology for fields as varied as Monte Carlo simulations and quantum information science. An important application is a secure quantum key distribution (QKD) system; here, we propose and demonstrate an approach to random number generation that satisfies the specific requirements for QKD. In our scheme, vacuum fluctuations of the electromagnetic-field inside a laser cavity are sampled in a discrete manner in time and amplified by injecting current pulses into the laser. Random numbers can be obtained by interfering the laser pulses with another independent laser operating at the same frequency. Using only off-the-shelf opto-electronics and fibre-optics components at 1.5 $μ$ m wavelength, we experimentally demonstrate the generation of high-quality random bits at a rate of up to 1.5 GHz. Our results show the potential of the new scheme for practical information processing applications.Random number generation is an enabling technology for fields as varied as Monte Carlo simulations and quantum information science. An important application is a secure quantum key distribution (QKD) system; here, we propose and demonstrate an approach to random number generation that satisfies the specific requirements for QKD. In our scheme, vacuum fluctuations of the electromagnetic-field inside a laser cavity are sampled in a discrete manner in time and amplified by injecting current pulses into the laser. Random numbers can be obtained by interfering the laser pulses with another independent laser operating at the same frequency. Using only off-the-shelf opto-electronics and fibre-optics components at 1.5 $μ$m wavelength, we experimentally demonstrate the generation of high-quality random bits at a rate of up to 1.5 GHz. Our results show the potential of the new scheme for practical information processing applications.

arXiv:1703.00559Mar 2, 201710 citations

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

Carlos Abellán, Waldimar Amaya, Marc Jofre +5 more

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.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.

arXiv:1401.5658Optics ExpressJan 16, 2014168 citations

New insights on quantum random number generation (QRNG) by phase diffusion (Conference Presentation)

Markus Gräfe, Brigitta Septriani, Oliver de Vries

Randomness is essential ingredient for applications in cryptography, stochastic simulation, and fundamental science experiments [American Scientist 89, 4 (2001); PRL 115, 25 (2015)]. Common practice is to generate random numbers from mathematical algorithm using Pseudo-random number generators. We are interested in tackling this problem with quantum technology. Phase diffusion in spontaneous emission events is a quantum phenomena with inherent randomness [Opt. Express 19, 21 (2011)]. Implementations of this scheme using pulsed lasers can yield high-speed quantum random number generation (QRNG) [Opt. Express 22, 2 (2014)]. The general interest in the laser phase diffusion QRNG setup has been mainly focused on and motivated by the speed of the random number generations. Little has been stated about the performance of quantum phase noise as a randomness source in QRNG, from the perspective of the physics involved. We reanalyze the process of phase diffusion based QRNG and give an intuitive explaining picture of the underlying physics. Our findings show that a pulsed process is beneficial over the continuous-wave approach and give a upper bound of maximum random bit rate for a given experimental setting. In detail, the output of a semiconductor laser contains fluctuations in intensity and phase. This was originally studied first by Charles Henry in 1982 [J. Lightwave Techn. 4, 3 (1986)]. Based on that one can identify two phenomena contributing to the phase noise, which takes the form of a random walk. First, there will be phase changes due to the carrier-induced change in refractive index in the semiconductor laser. Second, spontaneous emission events take place in the active medium [Opt. Express 19, 21 (2011)]. Naturally, taking spontaneous emission events into account necessitates the application of stochastic laser rate equations for theoretical description. We solve these equations numerically be a Monte-Carlo simulation and investigate several random walk scenarios. One of our essential findings is that the phase fluctuation becomes much larger in the pulsed laser regime than in the continuous-wave mode. Additionally, there is a natural limit on the maximum pulse repetition rate for a given pulse width, since the phase jumps become smaller for shorter pulse distances. Since phase measurement is not a feasible procedure for optical signals, the phase fluctuation needs to be converted to an observable macroscopic parameter such as the optical intensity. This can be done by using an interferometer setup. The whole experimental setting is shown in Fig. 2 (left). An DFB laser diode is modulated using gain-switching technique to generate uniform amplitude signals with random phases. Each signal interferes with neighboring pulses through an unbalanced Mach-Zehnder interferometer. The delay in one arm was set to equal to the pulse repetition rate. With this setup we investigate the influence of several parameters on the shape of the probability distribution determining the quality of QRNG. The theoretical as well as experimental findings can help to find physical standards for QRNG verification rather than the ones based on classical statistical information theory.Randomness is essential ingredient for applications in cryptography, stochastic simulation, and fundamental science experiments [American Scientist 89, 4 (2001); PRL 115, 25 (2015)]. Common practice is to generate random numbers from mathematical algorithm using Pseudo-random number generators. We are interested in tackling this problem with quantum technology. Phase diffusion in spontaneous emission events is a quantum phenomena with inherent randomness [Opt. Express 19, 21 (2011)]. Implementations of this scheme using pulsed lasers can yield high-speed quantum random number generation (QRNG) [Opt. Express 22, 2 (2014)]. The general interest in the laser phase diffusion QRNG setup has been mainly focused on and motivated by the speed of the random number generations. Little has been stated about the performance of quantum phase noise as a randomness source in QRNG, from the perspective of the physics involved. We reanalyze the process of phase diffusion based QRNG and give an intuitive explaining picture of the underlying physics. Our findings show that a pulsed process is beneficial over the continuous-wave approach and give a upper bound of maximum random bit rate for a given experimental setting. In detail, the output of a semiconductor laser contains fluctuations in intensity and phase. This was originally studied first by Charles Henry in 1982 [J. Lightwave Techn. 4, 3 (1986)]. Based on that one can identify two phenomena contributing to the phase noise, which takes the form of a random walk. First, there will be phase changes due to the carrier-induced change in refractive index in the semiconductor laser. Second, spontaneous emission events take place in the active medium [Opt. Express 19, 21 (2011)]. Naturally, taking spontaneous emission events into account necessitates the application of stochastic laser rate equations for theoretical description. We solve these equations numerically be a Monte-Carlo simulation and investigate several random walk scenarios. One of our essential findings is that the phase fluctuation becomes much larger in the pulsed laser regime than in the continuous-wave mode. Additionally, there is a natural limit on the maximum pulse repetition rate for a given pulse width, since the phase jumps become smaller for shorter pulse distances. Since phase measurement is not a feasible procedure for optical signals, the phase fluctuation needs to be converted to an observable macroscopic parameter such as the optical intensity. This can be done by using an interferometer setup. The whole experimental setting is shown in Fig. 2 (left). An DFB laser diode is modulated using gain-switching technique to generate uniform amplitude signals with random phases. Each signal interferes with neighboring pulses through an unbalanced Mach-Zehnder interferometer. The delay in one arm was set to equal to the pulse repetition rate. With this setup we investigate the influence of several parameters on the shape of the probability distribution determining the quality of QRNG. The theoretical as well as experimental findings can help to find physical standards for QRNG verification rather than the ones based on classical statistical information theory.

Quantum Communications and Quantum ImagingSep 10, 20191 citation

Practical quantum random‐number generation based on sampling vacuum fluctuations

Qiang Zhou, Raju Valivarthi, Caleb John +1 more

Random-number generation is an enabling technology for fields as varied as Monte Carlo simulations and quantum information science, particularly secure quantum key distribution. Here, we propose and demonstrate an approach to random-number generation that satisfies the specific requirements for quantum key distribution. In our scheme, vacuum fluctuations of the electromagnetic field inside a laser cavity are sampled in a discrete manner in time and amplified by injecting current pulses into the laser. Random numbers can be obtained by interfering the laser pulses with another independent laser operating at the same frequency. Using only off-the-shelf optoelectronics and fiber-optic components at a 1.5-μm wavelength, we experimentally demonstrate the generation of high-quality random bits at a rate of up to 1.5 GHz. Our results show the potential of the new scheme for practical information-processing applications.Random-number generation is an enabling technology for fields as varied as Monte Carlo simulations and quantum information science, particularly secure quantum key distribution. Here, we propose and demonstrate an approach to random-number generation that satisfies the specific requirements for quantum key distribution. In our scheme, vacuum fluctuations of the electromagnetic field inside a laser cavity are sampled in a discrete manner in time and amplified by injecting current pulses into the laser. Random numbers can be obtained by interfering the laser pulses with another independent laser operating at the same frequency. Using only off-the-shelf optoelectronics and fiber-optic components at a 1.5-μm wavelength, we experimentally demonstrate the generation of high-quality random bits at a rate of up to 1.5 GHz. Our results show the potential of the new scheme for practical information-processing applications.

Quantum EngineeringMar 1, 201944 citations

μ

m wavelength, we experimentally demonstrate the generation of high-quality random bits at a rate of up to 1.5 GHz. Our results show the potential of the new scheme for practical information processing applications.