A 2-Gbps low-SWaP quantum random number generator with photonic integrated circuits for satellite applications

We introduce a low size, weight and power quantum random number generator (QRNG) utilizing compact integrated photonic asymmetric Mach-Zehnder interferometers (AMZIs). Our QRNG is based on phase-diffusion in two gain-switched lasers interfered within two separate chip-AMZIs. By substituting the high-bit analog-to-digital converters, typically employed to digitize the random intensity signal from each laser, with clocked comparators we significantly reduce both the complexity and power consumption of the device. Furthermore, by performing the exclusive OR (XOR) operation on the output random bits of each channel we are able to reduce the processing requirements. The QRNG architecture can be integrated with an overhead power consumption of just 7.93 W, accounting for the opto-electronics and FPGA implementation, providing fast random number generation at up to 2 Gbps. We demonstrate the real-time seeding of a free-space decoy-state quantum key distribution system using our QRNG. Our design and implementation provides a practical solution for QRNGs requiring low-power and high bit rates. This advancement is important for practical QRNGs and particularly for application in resource-constrained environments such as space-based quantum key distribution.