Darius Bunandar, Anthony Lentine, Catherine Lee, Hong Cai, Christopher M. Long, Nicholas Boynton, Nicholas Martinez, Christopher DeRose, Changchen Chen, Matthew Grein, Douglas Trotter, Andrew Starbuck, Andrew Pomerene, Scott Hamilton, Franco N. C. Wong, Ryan Camacho, Paul Davids, Junji Urayama, and Dirk Englund
Photonic integrated circuits (PICs) provide a compact and stable platform for quantum photonics. Here we demonstrate a silicon photonics quantum key distribution (QKD) transmitter in the first high-speed polarization-based QKD field tests. The systems reach composable secret key rates of 950 kbps in a local test (on a 103.6‑m fiber with a total emulated loss of 9.2 dB) and 106 kbps in an intercity metropolitan test (on a 43-km fiber with 16.4 dB loss). Our results represent the highest secret key generation rate for polarization-based QKD experiments at a standard telecom wavelength and demonstrate PICs as a promising, scalable resource for future formation of metropolitan quantum-secure communications networks.