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 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 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 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.
Quantum random number generators play a crucial role in securing high-demand information contexts by producing true random numbers. Nevertheless, the large volume and high cost limit their widespread use. Here, we propose a system on-chip that fully leverages the advantages of different photonic integrated platforms, where the interference optical paths and photodiodes are integrated on a standard silicon process, while the laser source on-chip is realized on a III–V platform. Using micro-lens coupling package technology, which contributes to a topnotch coupling loss lower than 2 dB, the components on different platforms are combined and packaged with the amplifier circuits in a 42 mm × 24 mm footprint in a butterfly form. This complete miniaturized and cost-effective entropy source enables outputting a vacuum noise signal with a 3-dB bandwidth of over 500 MHz. After sampling and post-processing, a random number generation rate of up to 6.57 Gbps is achieved. The results show a feasible way of overcoming the laser integration problem with silicon-based integrated quantum photonics. Foreseeable, commercial applications on a large scale are substantially promoted.
Quantum random number generators are widely used in many applications, ranging from sampling and simulation, fundamental science to cryptography, such as a quantum key distribution system. Among all the previous works, quantum noise from phase fluctuation of laser diodes is one of the most commonly used random source in the quantum random number generation, and many practical schemes based on phase noise with compact systems have been proposed so far. Here, we proposed a new structure of phase noise scheme, utilizing the phase fluctuation from two laser diodes with a slight difference of center wavelength. By analyzing the frequency components and adopting an appropriate band-pass filter, we prove that our scheme extracts quantum noise and filtered other classical noises substantially. Results of a randomness test shows that the extracted random sequences are of good performance. Due to lack of delay-line and the low requirement on other devices in this system, our scheme is promising in future scenarios for miniaturized quantum random number generation systems.
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.