Random numbers are a fundamental resource in science and technology. Among the different approaches to generating them, random numbers created by exploiting the laws of quantum mechanics have proven to be reliable and can be produced at enough rates for their practical use. While these demonstrations have shown very good performance, most of the implementations using free-space and fibre optics suffer from limitations due to their size, which strongly limits their practical use. Here we report a quantum random number generator based on phase fluctuations from a diode laser, where the other required optical components are integrated on a mm-scale monolithic silicon-on-insulator chip. The post-processing reported in this experiment is performed via software. However, our physical device shows the potential of operation at generation rates in the Gbps regime. Considering the device's size, its simple, robust and low power operation, and the rapid industrial uptake of silicon photonics, we foresee the widespread integration of the reported design in more complex systems.
Random numbers are a fundamental resource in science and technology. Among the different approaches to generating them, random numbers created by exploiting the laws of quantum mechanics have proven to be reliable and can be produced at enough rates for their practical use. While these demonstrations have shown very good performance, most of the implementations using free-space and fibre optics suffer from limitations due to their size, which strongly limits their practical use. Here we report a quantum random number generator based on phase fluctuations from a diode laser, where the other required optical components are integrated on a mm-scale monolithic silicon-on-insulator chip. The post-processing reported in this experiment is performed via software. However, our physical device shows the potential of operation at generation rates in the Gbps regime. Considering the device's size, its simple, robust and low power operation, and the rapid industrial uptake of silicon photonics, we foresee the widespread integration of the reported design in more complex systems.
Random numbers are a fundamental resource in science and technology. Among the different approaches to generating them, random numbers created by exploiting the laws of quantum mechanics have proven to be reliable and can be produced at enough rates for their practical use. While these demonstrations have shown very good performance, most of the implementations using free-space and fibre optics, suffer from limitations due to their size, which strongly limits their practical use. Here we report a quantum random number generator based on phase fluctuations from a diode laser, where the other required optical components are integrated on a mm-scale monolithic silicon-on-insulator chip. Our device operates with generation rate in the Gbps regime and the output random numbers pass the NIST statistical tests. Considering the device's size, its simple, robust and low power operation, and the rapid industrial uptake of silicon photonics, we foresee the widespread integration of the reported design in more complex systems.
Random numbers find applications in a range of different fields, from quantum key distribution and classical cryptography to fundamental science.They also find extensive use in gambling and lotteries.By exploiting the probabilistic nature of Quantum Mechanics, quantum random number generators (QRNGs) provide a secure and efficient means to produce random numbers.Most of the quantum random number generators demonstrated so far have been built in bulk optics, either using free space or fibre-optic components.While showing good performance, most of these demonstrations are strongly limited in real life applications, due to issues such as size, costs and the manufacturing process.In this thesis I report the demonstration of three different QRNGs based on integrated photonics.First, I demonstrated a QRNG based on homodyne measurement of optical vacuum states on a Silicon-on-insulator (SOI) chip.Second, I developed a SOI QRNG based on phase fluctuations from a laser diode.In these two schemes all the optical and opto-electronic components, excluding the laser, were integrated onto a silicon-on-insulator device.These schemes, being built on a silicon-on-insulator chip are potentially CMOS compatible and pave the way for being integrated onto other more complex systems.These QRNGs showed Gbps generation rates and passed the statistical tests provided by NIST.Third, I report the preliminary study of a QRNG based on homodyne measurement of optical vacuum states onto a Indium Phosphide (InP) chip.In this third experiment, all the components, including a laser diode, were monolithically integrated in the same chip, which provide a great advantage in terms of the overall size of the optics of the device.First, I would like to thank Jonathan, for the opportunity to pursue my PhD and for guiding my research in these four years.Thank you for giving me the chance to follow my curiosity and for pushing me to get the best out of my research.Thank you, Dylan, for being so helpful, always ready to answer my questions.I would like to thank Giacomo for sharing a big part of my research in these years
Recent advancements in integrated photonics have shown great promise for the serial production of chip-scale quantum random number generators (QRNG). Considerable progress has been made towards developing fully on-chip QRNGs that exploit the interference of phase-randomized fields from two independent lasers. While a common alternative design, based on a single laser and interferometer, would further improve power consumption and ease of operation, monolithic integration of such a design has thus far faced challenges, including high losses and crosstalk. We solve these key challenges and report fast single-laser interferometric QRNGs integrated onto monolithic chips. By combining on-chip optical amplification with electronic common-mode rejection techniques, our photonic integrated circuits (PICs) stably convert the spontaneous emission phase noise of a diode laser into electronic pulses of high-contrast random intensity at GHz clock rates. Using real-time, hash-function-based randomness extraction, uniformly distributed, truly unpredictable random numbers are generated at a rate of 3 Gbps.
The quantum random number generator (QRNG) operates based on fundamental quantum mechanical principles to produce high-quality random numbers. Recently, chip-based QRNGs have garnered significant attention due to their compact size, low cost, and reduced power consumption. In this work, we demonstrate a hybrid integrated QRNG leveraging continuous-wave (CW) laser phase fluctuations. Using advanced hybrid packaging techniques, we integrate a tunable, unbalanced Mach-Zehnder interferometer (uMZI), laser, and InGaAs photodiode (PD) within a 14-pin butterfly package. To enhance the long-term stability and reliability of the QRNG, a negative temperature coefficient (NTC) thermistor is also attached to the chip for thermal regulation. The resulting integrated QRNG has a footprint of just 30 mm × 12.7 mm, and delivers a random number generation rate of 4.68 Gbps after min-entropy evaluation and post-processing. The combination of compact size and high-speed performance makes this hybrid integrated QRNG ideal for high-speed, large-scale applications.
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.
Random numbers are essential resources in science and engineering, with indispensable applications in simulation, cybersecurity, and finance. Quantum random number generators (QRNGs), based on the principles of quantum mechanics, ensure genuine randomness and unpredictability. Silicon photonics enables the large-scale deployment of integrated QRNGs due to its low cost, miniaturization, and compatibility with CMOS technology. However, current integrated QRNGs are typically based on perfect or partially perfect device models, deviating from real-world devices, which compromises the unpredictability of quantum random numbers. In this study, we implemented a silicon-based QRNG that makes no assumptions about the source and only uses trusted but uncharacterized measurement devices. In experimental demonstration, we show that our setup can generate secure random numbers with different choices of intensities of laser light, and achieve an optimized random number generation rate of up to 4.04 Mbps. Our work significantly advances the security, practicality, and commercial development of QRNGs by employing imperfect devices.