CUED Publications database

Modulator‐Free Coherent‐One‐Way Quantum Key Distribution

Roberts, GL and Lucamarini, ML and Dynes, JFD and Savory, SJS and Yuan, ZLY and Shields, AJS (2017) Modulator‐Free Coherent‐One‐Way Quantum Key Distribution. Laser & Photonics Reviews, 2017. p. 1700067. ISSN 1863-8880 (Unpublished)

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Time-bin encoding is an attractive method for transmitting photonic qubits over long distances with minimal decoherence. It allows a simple receiver for quantum key distribution (QKD) that extracts a key by measuring time of arrival of photons and detects eavesdropping by measuring interference of pulses in different time bins. In the past, coherent pulses have been generated using a CW laser and an intensity modulator. A greatly simplified transmitter is proposed and demonstrated here that works by directly modulating the laser diode. Coherence between pulses is maintained by a weak seed laser. The modulator-free source creates time-bin encoded pulses with a high extinction ratio (29.4 dB) and an interference visibility above 97 %. The resulting QKD transmitter gives estimated secure key rates up to 4.57 Mbit/s, the highest yet reported for coherentone- way QKD, and can be programmed for all protocols using weak coherent pulses.

Item Type: Article
Divisions: Div B > Photonics
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 19:20
Last Modified: 13 Apr 2021 08:55
DOI: 10.1002/lpor.201700067