Source-linked AI summary
Chip-based Quantum Key Distribution
Philip Sibson, Chris Erven, Mark Godfrey, Shigehito Miki, Taro Yamashita, Mikio Fujiwara, Masahide Sasaki, Hirotaka Terai, Michael G. Tanner, Chandra M. Natarajan, Robert H. Hadfield, Jeremy L. O'Brien, Mark G. Thompson
TL;DR
QKD has not been widely adopted, and large-scale deployment requires integrated devices combining compactness, robustness, reconfigurability, and compatibility with communication networks. This work demonstrates a reconfigurable chip-to-chip system implementing BB84, COW, and DPS with low error rates and performance comparable to current fibre and bulk-optical systems.
Problem
Large-scale QKD deployment requires compact, robust, reconfigurable devices compatible with photonic and electronic communication infrastructure.
Method
The authors use monolithically integrated InP transmitter and SiOxNy receiver chips with reconfigurable photonic components to implement BB84, COW, and DPS.
Results
BB84, COW, and DPS achieved estimated secret key rates of 345 kbits/s, 311 kbits/s, and 565 kbits/s, respectively, with QBERs below 1.4% at attenuation equivalent to 20 km of fibre.
Takeaways & Limitations
The integrated photonic platform demonstrates QKD devices with miniaturisation, manufacturing robustness, protocol flexibility, and compatibility with classical communication hardware.
Takeaways & Limitations
The experiments assumed 0.2 dB/km fibre loss and treated dispersion as negligible for the broad approximately 150 ps pulses used.
Abstract
from arXiv · showhide
Improvement in secure transmission of information is an urgent practical need for governments, corporations and individuals. Quantum key distribution (QKD) promises security based on the laws of physics and has rapidly grown from proof-of-concept to robust demonstrations and even deployment of commercial systems. Despite these advances, QKD has not been widely adopted, and practical large-scale deployment will likely require integrated chip-based devices for improved performance, miniaturisation and enhanced functionality, fully integrated into classical communication networks. Here we report low error rate, GHz clocked QKD operation of an InP transmitter chip and a SiO$_x$N$_y$ receiver chip --- monolithically integrated devices that use state-of-the-art components and manufacturing processes from the telecom industry. We use the reconfigurability of these devices to demonstrate three important QKD protocols --- BB84, Coherent One Way (COW) and Differential Phase Shift (DPS) --- with performance comparable to state-of-the-art. These devices, when combined with integrated single photon detectors, satisfy the requirements at each of the levels of future QKD networks --- from point-of-use through to backbone --- and open the way to operation in existing and emerging classical communication networks.