TOWARDS A SPACE-BASED QUANTUM KEY DISTRIBUTION NETWORK: DEVELOPING A MINIATURIZED POLARISATION ENTANGLED PHOTON PAIR SOURCE FOR NANOSATELLITE

Abstract

Quantum key distribution (QKD) based on entangled photon pairs provides provable security underpinned by quantum physics. Current QKD networks have distance limits due to loses and satellite technology can be used to extend this network. We propose an iterative and cost effective approach to this challenge using an emerging Nanosatellite standard called CubeSat. The first step towards this direction is to demonstrate a miniaturised polarisation entangled photon pair source that is compatible with the resource-limited CubeSat. This thesis presents the development of such a source based on type I spontaneous parametric downconversion (SPDC). The initial prototype of the source was tested on a weather balloon 35.5 km in altitude. Subsequently, we have tested the revised prototype in two space missions (GomX-2 and Galassia-NUS). These results establish space heritage for the components used and provide insights to refine the design leading to a space qualified QKD source.