On-Chip Tamper-Resistant Quantum Entropy Source Enabled by Monolithic Emitter-Detector Integration

We demonstrate the first monolithic integration of a photodetector (PD) directly onto a vertical-cavity surface-emitting laser (VCSEL) on a single chip to form a compact optical entropy source for quantum random number generation (QRNG) aimed at embedded hardware security applications. In contrast to conventional hardware RNG configurations that rely on discrete components, our system exploits intensity fluctuations from a VCSEL captured in situ by the co-integrated PD without any external optics, amplification or careful alignment. This monolithic approach minimizes system operation, reduces footprint, and enables scalable, no-leakage, parallel, and alignment-free RNG, making it ideally suited for secure edge devices. The extracted random bitstream achieves an RNG rate of 10 Gb/s from every single channel. The random numbers successfully pass the full NIST statistical randomness test suite. This work establishes a new class of on-chip photonic entropy sources and lays the foundation for embedded secure hardware-based cryptographic systems.