Continuous-variable Quantum Key Distribution protocols with eight-state discrete modulation

Becir, A.; El-Orany, Faisal A. A.; Wahiddin, Mohamed Ridza

doi:10.48550/arxiv.1006.4216

Cited by 1 publication

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“…Different CV-QKD protocols have been proposed so far including protocols based on squeezed states of the electromagnetic field [39] or on discrete modulations of coherent states [40,41]. However, squeezed states are experimentally challenging to produce and security analysis for discrete modulation CV-QKD are less advanced.…”

Section: Cv-qkd: Protocol and Noise Modelmentioning

confidence: 99%

Self-coherent phase reference sharing for continuous-variable quantum key distribution

Marie¹,

Alléaume²

2017

Phys. Rev. A

102

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We develop a comprehensive framework to model and optimize the performance of CV-QKD with a local local oscillator (LLO), when phase reference sharing and QKD are conjointly implemented with the same hardware. We first analyze the limitations of the only existing approach, called LLO-sequential, and show that it requires high modulation dynamics and can only tolerate small phase noise, leading to expensive hardware requirements. Our main contribution is to introduce two original designs to perform LLO CV-QKD with shared hardware" respectively called LLO-delayline and LLO-displacement, and to study their performance. Both designs rely on a self-coherent approach, in which phase reference information and quantum information are coherently obtained from a single optical wavefront.We show that these designs can lift some important limitations of the existing LLO-sequential approach. The LLO-delayline design can in particular tolerate much stronger phase noise and thus appears as an appealing alternative to LLO-sequential that can moreover be deployed with affordable hardware. We also investigate, with the LLO-displacement design, how phase reference information and quantum information can be multiplexed in a single optical pulse. By studying the trade-off between phase reference recovery and phase noise induced by displacement we however demonstrate that this design can only tolerate low phase noise. On the other hand, the LLO-displacement design has the advantage of minimal hardware requirements and can be applied to multiplex classical and quantum communications, opening practical path towards the development of coherent quantum communications systems compatible with next-generation networks requirements. * Electronic address: adrien.marie@telecom-paristech.fr arXiv:1605.03642v2 [quant-ph] 30 Aug 2016 on the reference frame allows the receiver to more faithfully translate the received physical signals into logical information. It can for example consist in the knowledge of the relative angle between spatial two-dimensional cartesian reference frames [16], in the synchronization of spatially separated clocks [17], or information about the relative phase between two lasers, respectively at emitter and receiver side, when coherent optical communication is performed [15]. This latter problem, phase reference frame sharing considered in the context of CV-QKD, will be the main focus of this article .The problem of sharing a reference frame is specific in the sense that reference frame information constitutes unspeakable information, that can only be shared through physical carriers exchanged between emitter and receiver [18]. On the other hand, it is important to emphasize that although quantum mechanics gives a precise framework to formulate the question of reference frame sharing, in relation with quantum metrology [18], this question can be solved "classically", using macroscopic signals to exchange reference frame information. The type of questions related to phase reference sharing is not whether it is possible, bu...

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Section: Cv-qkd: Protocol and Noise Modelmentioning

confidence: 99%