Device-independent, high bit-rate quantum random number generator with beam-splitter-free architecture and live Bell test certification

Abstract

We present a beam-splitter-free, high-bit rate, device-independent quantum random number generator (DI-QRNG) with real-time quantumness certification via live Bell test data. Using a 20-mm-long, type-0 phase-matched PPKTP crystal in a polarization Sagnac interferometer, we generated degenerate, non-collinear parametric down-converted entangled photons at 810 nm in an annular ring distribution with pair photons appearing at diametrically opposite points on the ring randomly. Dividing the ring into six sections and collecting photons from opposite sections, we developed three entangled photon sources from a single resource (optics, laser, and nonlinear crystal). Using a pump power of 12.4 mW at 405 nm, we recorded coincidence (1 ns window) timestamps of any two sources without projection to assign random bits (0 and 1) while measuring the Bell parameter (S > 2) with the third source for live quantumness certification. We have generated 90 million raw bits in 46.4 seconds, with a minimum entropy extraction ratio exceeding 97%. Post-processed using a Toeplitz matrix, the QRNG achieved a 1.8 Mbps bit rate, passing all NIST 800-22 and TestU01 tests. Increasing the coincidence window to 2 ns boosts the bit rate to over 2 Mbps, maintaining minimum entropy above 95% but reducing the Bell parameter to S = 1.73. This novel scalable scheme eliminates beam splitters, enabling robust, multi-bit DI-QRNG with enhanced ring sectioning and trustworthy certification for practical high-rate applications.