Mutually Independent Multi-Channel High-Speed Quantum Random Number Generation using a Programmable Photonic Integrated Circuit

Real-time high-speed mutually independent two-channel quantum random number generator (QRNG) device has been proposed using a programmable photonic integrated circuit in silicon photonics platform. Broadband random fluctuations of quantum photonic waveguide vacuum mode is harnessed in each of the mutually independent channels by mixing a guided coherent laser light operating at λ ∼ 1550 nm. All classical noises arising out of electrical, mechanical, thermal disturbances, etc. are minimized by the use of homodyne detection and appropriate programming of the photonic integrated circuit. The method of classical noise elimination has been supported with an appropriate theoretical modeling and experimental observations. The raw random number generation rate per channel was 4 Gbps, when the output signal from the homodyne detectors (bandwidth 1.6 GHz) was sampled at 500 MSa/s and subsequently digitized by a 14-bit analog-to-digital converter. We have also shown that the proposed PPIC design can be scaled up to higher number of channels using CMOS fabrication process compatible silicon photonics technology. Such mutually independent multi-channel QRNG sources are especially useful for high-speed chip-scale quantum key distribution (QKD) transceivers.