Innocenzo De Marco

Random numbers play a crucial role in information technology, particularly as digital communication capacity continues to expand. Consequently, the need for secure and high-rate random number generation has become increasingly urgent. While integrated photonics technology holds promise for mass-producing optoelectronic quantum random number generators (QRNGs), there remains a challenge in developing fast, robust, and scalable solutions suitable for industrial deployment. Addressing this challenge, we present a fast QRNG solution in this study, leveraging a photonic integrated circuit (PIC) directly embedded onto a versatile electronic platform. Designed to withstand real-world applications, our PIC is packaged to align with industrial electronic assembly lines. To rigorously assess scalability and stability, these generators underwent week-long periods of continuous GHz operation. Furthermore, a QRNG was integrated into a quantum key distribution system, where despite operating in an uncontrolled environment, minimal variations in physical randomness were observed over 38 days, as measured from 2.9 million histograms. Finally, we implemented a security model for the QRNGs, enabling rate adjustment to match the actual randomness content and demonstrating secure generation at 2 Gbit/s.

Integrated photonics presents an opportunity for low-cost and highly-reproducible quantum cryptographic systems. However, due to numerous challenges such as packaging, power consumption and interfacing multiple chips in real, a standalone deployable photonic integrated system is still missing. Here we address all these challenges to present a real-time quantum communication system using integrated photonics. The system operated without intervention over multiple days and is capable of secure key rates of > 470 kbps over 10 km of fiber

We propose a QKD transmitter that is able to encode qubits in two different degrees of freedom, namely polarisation and time-bin/phase, and according to different protocols, including but not limited to BB84, DPS and COW.