Advances in quantum computing are a rapidly growing threat towards modern cryptography. Quantum key distribution (QKD) provides long-term security without assuming the computational power of an adversary. However, inconsistencies between theory and experiment have raised questions in terms of real-world security, while large and power-hungry commercial systems have slowed wide-scale adoption. Measurement-device-independent QKD (MDI-QKD) provides a method of sharing secret keys that removes all possible detector side-channel attacks which drastically improves security claims. In this letter, we experimentally demonstrate a key step required to perform MDI-QKD with scalable integrated devices. We show Hong-Ou-Mandel interference between weak coherent states carved from two independent indium phosphide transmitters at 431 MHz with a visibility of 46.5±0.8%. This work demonstrates the feasibility of using integrated devices to lower a major barrier towards adoption of QKD in metropolitan networks.
@article{arxiv.1901.05706,
title = {Interference between independent photonic integrated devices for quantum key distribution},
author = {Henry Semenenko and Philip Sibson and Mark G. Thompson and Chris Erven},
journal= {arXiv preprint arXiv:1901.05706},
year = {2019}
}