Source-linked AI summary
Integrated Silicon Photonics for High-Speed Quantum Key Distribution
Philip Sibson, Jake E. Kennard, Stasja Stanisic, Chris Erven, Jeremy L. O'Brien, Mark G Thompson
TL;DR
High-speed quantum-state modulation in standard silicon photonics is limited by slow thermo-optic modulators and non-ideal fast carrier-depletion modulators. This work combines thermo-optic DC biases with fast carrier-depletion modulation to demonstrate low-error QKD across three implementations, including key rates up to 916 kbps over 20 km of fibre.
Problem
High-speed quantum-state modulation in standard silicon photonic fabrication is limited, while fast carrier-depletion modulators introduce phase-dependent loss and saturation that harm quantum state preparation.
Method
The authors combine slow, high-fidelity thermo-optic phase modulators for static biases with fast carrier-depletion modulators for limited-depth QKD state preparation and pulse modulation.
Results
The integrated devices demonstrate COW, polarisation BB84, and time-bin BB84 operation, with estimated secret key rates up to 916 kbps and QBER as low as 1.01% over 20 km of fibre.
Takeaways & Limitations
The results experimentally demonstrate the feasibility of high-speed QKD transmitters in CMOS-based silicon photonic integrated circuits.
Takeaways & Limitations
Complete autonomous QKD operation still requires real-time random basis and bit selection, active basis alignment, error reconciliation, privacy amplification, and finite-key security analysis.
Abstract
from arXiv · showhide
Integrated photonics offers great potential for quantum communication devices in terms of complexity, robustness and scalability. Silicon photonics in particular is a leading platform for quantum photonic technologies, with further benefits of miniaturisation, cost-effective device manufacture and compatibility with CMOS microelectronics. However, effective techniques for high-speed modulation of quantum states in standard silicon photonic platforms have been limited. Here we overcome this limitation and demonstrate high-speed low-error quantum key distribution modulation with silicon photonic devices combining slow thermo-optic DC biases and fast (10~GHz bandwidth) carrier-depletion modulation. The ability to scale up these integrated circuits and incorporate microelectronics opens the way to new and advanced integrated quantum communication technologies and larger adoption of quantum-secured communications.