Optimisation of Optical Network for Continuous-Variable Quantum Key Distribution by Means of Simulation

Abstract

The unprecedented breakthrough in the field of quantum computing in the last several years is threatening with the exploitation of our current communication systems. To address this issue, researchers are getting more involved in finding methods to protect these systems. Amongst other tools, quantum key distribution could be a potentially applicable way to achieve the desired level of protection. In this paper we are evaluating the physical layer of an optical system realising continuous variable quantum key distribution (CVQKD) with simulations to determine its weak points and suggest methods to improve them. We found that polarisation dependent devices are crucial for proper operation, therefore we determined their most defining parameters from the point of operation and suggested extra optical devices to largely improve transmission quality. We also paid attention to polarisation controlling in these sort of systems. Our findings could be valuable as practical considerations to construct reliable CVQKD optical transmission links.