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A direct GHz-clocked phase and intensity modulated transmitter applied to quantum key distribution

Published version
Peer-reviewed

Type

Article

Change log

Authors

Lucamarini, M 
Dynes, JF 
Savory, SJ 
Yuan, ZL 

Abstract

Quantum key distribution (QKD), a technology that enables perfectly secure communication, has evolved to the stage where many different protocols are being used in real-world implementations. Each protocol has its own advantages, meaning that users can choose the one best-suited to their application, however each often requires different hardware. This complicates multi-user networks, in which users may need multiple transmitters to communicate with one another. Here, we demonstrate a direct-modulation based transmitter that can be used to implement most weak coherent pulse based QKD protocols with simple changes to the driving signals. This also has the potential to extend to classical communications, providing a low chirp transmitter with simple driving requirements that combines phase shift keying with amplitude shift keying. We perform QKD with concurrent time-bin and phase modulation, alongside phase randomisation. The acquired data is used to evaluate secure key rates for time-bin encoded BB84 with decoy states and a finite key-size analysis, giving megabit per second secure key rates, 1.60 times higher than if purely phase-encoded BB84 was used.

Description

Keywords

quantum cryptography, quantum key distribution, quantum communications

Journal Title

Quantum Science and Technology

Conference Name

Journal ISSN

2058-9565
2058-9565

Volume Title

3

Publisher

IOP Publishing
Sponsorship
EPSRC (1635675)
Engineering and Physical Sciences Research Council (EP/G037256/1)
EPSRC (via University of York) (EP/M013472/1)
Royal Commission for the Exhibition of 1851