Robust Polarisation Basis Alignment for Satellite-based Quantum Key Distribution

Andersohn, Marco (2021): Robust Polarisation Basis Alignment for Satellite-based Quantum Key Distribution. Masterarbeit, Ludwig-Maximilians-Universität München

Abstract

Quantum key distribution (QKD) is a secure key-transmitting method based on quantum mechanics to deliver private keys for encryption. Satellite QKD is a promising technique that overcomes the limited transmission distance in optical-fibre-based systems. To enable polarisation encoded QKD, polarisation reference-frame mismatches between the satellite and a receiving optical ground station (OGS) have to be compensated. We developed and implemented a compensation method for a BB84 protocol designed QKD receiver by an additional set of three waveplates (HWP, QWP, QWP). In simulations and laboratory demonstrations, we show the robustness under conditions that we expect on our future satellite downlink mission. As a result, we expect good compensation quality for a wide range of signal to noise ratios and satellite rotation frequencies by requiring only a few signal photons of 2000 of two non-orthogonal polarisation states, respectively, to measure the reference-frame mismatch used for one compensation sequence.

• Dokumententyp: Hochschulschrift (Masterarbeit)
• Fakultät: Physik > Studienabschlussarbeiten ; Physik > Laserphysik und Quantenoptik
• Themengebiete: 500 Naturwissenschaften und Mathematik > 530 Physik
• Sprache: Englisch