Skip to Main content Skip to Navigation
Theses

Design and implementation of high-performance devices for continuous-variable quantum key distribution

Abstract : Quantum key distribution (QKD) is one of the first quantum technologies that were able to provide commercially meaningful solutions to the problem of distributing cryptographic keys between trusted parties, guaranteeing long term security. It is now progressing towards technical maturity, by proposing multiple implementation alternatives. In this thesis, we study Continuous-Variables QKD (CV-QKD), which shares many common elements with classical coherent communication systems, and is a good candidate to facilitate the access to QKD for more users.The use of digital signal processing (DSP) techniques typical in classical communications has been only partially exploited in previous CV-QKD implementations. We experimentally implement standard telecommunication techniques like pulse shaping, adaptive filtering and mode recovery in order to improve the quantum secret key rate and optimize the occupied bandwidth.The potential of integration of the components in a photonic integrated circuit (PIC) is another important aspect of CV-QKD. We have tested a silicon photonics PIC integrating a 180º hybrid detector with two germanium photodiodes, showing that measured parameters are compatible with the generation of secret key.One of the most limiting factors of QKD is the performance under lossy channels, which is common in optical fibre for distances in the order of hundred kilometers. The range can be significantly extended using free space communications, and in particular satellites, where the losses at longer distances can be lower than those in fibre. We consider a model for a downlink satellite channel and predict the achievable secret key rates at different altitudes for CV-QKD, resulting in a potentially feasible technology for satellite communications, extending the range to intercontinental distances.
Document type :
Theses
Complete list of metadatas

Cited literature [123 references]  Display  Hide  Download

https://pastel.archives-ouvertes.fr/tel-02516921
Contributor : Abes Star :  Contact
Submitted on : Tuesday, March 24, 2020 - 10:53:12 AM
Last modification on : Wednesday, September 30, 2020 - 3:33:40 AM
Long-term archiving on: : Thursday, June 25, 2020 - 1:09:01 PM

File

83948_TRIGO_VIDARTE_2019_archi...
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-02516921, version 1

Citation

Luis Trigo Vidarte. Design and implementation of high-performance devices for continuous-variable quantum key distribution. Optics [physics.optics]. Université Paris Saclay (COmUE), 2019. English. ⟨NNT : 2019SACLO021⟩. ⟨tel-02516921⟩

Share

Metrics

Record views

252

Files downloads

559