Experimental Quantum Key Distribution with Integrated Silicon Photonics and Electronics

In the burgeoning field of quantum secure communication, the ``chipization'' and integration of quantum key distribution (QKD) systems is a prime topic. Here the authors demonstrate a prototype of an integrated optoelectronic QKD transmitter: a photonics chip that integrates the essential encoding components for the decoy-state BB84 protocol, plus electronics chips that integrate the dedicated driving circuits. Experiments at a repetition rate of 312.5 MHz verify the system's performance. This work takes a key step toward system-in-package QKD applications.