We present a high-speed continuous-variable quantum random number generator (QRNG) based on heterodyne detection of vacuum fluctuations. The scheme follows a source-device-independent (SDI) security model in which the entropy originates from quantum measurement uncertainty and no model of the source is required; security depends only on the trusted measurement device and the calibrated discretization, and thus remains valid even under adversarial state preparation. The optical field is split by a 90
∘ optical hybrid and measured by two balanced photodiodes to obtain both quadratures of the vacuum state simultaneously. The analog outputs are digitized using a dual-channel 12-bit analog-to-digital converter operating at a sampling rate of 3.2 GS/s per channel, and processed in real time by an FPGA implementing Toeplitz hashing for randomness extraction. The quantum-to-classical noise ratio was verified through calibrated power spectral density measurements and cross-checked in the time domain, confirming vacuum-noise dominance within the 1.6 GHz detection bandwidth. After extraction, the system achieves a sustained generation rate of
Rnet=33.92 Gbit/s of uniformly distributed random bits, which pass all NIST and Dieharder statistical tests. The demonstrated platform provides a compact, FPGA-based realization of a practical heterodyne continuous-variable source-independent QRNG suitable for high-rate quantum communication and secure key distribution systems.
Unpredictable random number (RN) generation is an essential technology for cryptographic applications. Quantum RN generators (QRNGs) have attracted significant attention owing to their generation of RNs utilizing the randomness guaranteed by quantum mechanics. Vacuum fluctuations are a promising entropy source of quantum randomness. These are detected using a homodyne setup with a laser source and a beam splitter. QRNGs based on vacuum fluctuations can generate RNs at a high-speed and in a stable manner. This paper reports a high-speed spatially multiplexed QRNG based on vacuum fluctuations using a single semiconductor laser diode and an integrated optical beam splitter. The QRNG obtained four independent vacuum fluctuations across a wide bandwidth of over 2 GHz. The RNs were extracted in parallel using a field-programmable gate array with analog-to-digital converters. An aggregated real-time RN generation rate of 4×12.5 Gbit/s was achieved. The generated RNs passed a randomness test based on NIST SP800-90B.