Work

Enhanced Extinction Ratio in QKD Transmitters Using On-Chip Saturable Absorbers

Year: 2026

Type: article

Abstract: We demonstrate an integrated quantum key distribution (QKD) transmitter with enhanced extinction ratio (ER) using a monolithically integrated saturable absorber (SA). Since the light is later attenuated to the weak-coherent-state level, the additional signal loss in the SA does not impair performance. The SA improves the ER by 3.6 dB at 1 GHz, corresponding to an estimated ∼50% relative reduction in quantum bit error rate and a ∼17% increase in secret key rate, offering a compact, low-complexity route to improved secure key rates in practical QKD systems.

Source: IEEE Photonics Technology Letters

DOI: 10.1109/lpt.2026.3661870

Authors: Julian Konig, Ozan Çirkinoğlu, Rajib R. Ghosh, Martijn J. R. Heck, Xaveer J. M. Leijtens

Institution: Eindhoven University of Technology

Language: English

Topic: Quantum Information and Cryptography

Subfield: Artificial Intelligence

Field: Computer Science

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $2,645

Funders: European Commission, HORIZON EUROPE Framework Programme