Effect of filter shape on excess noise performance in continuous variable quantum key distribution with Gaussian modulation

TL;DR

This paper investigates how the shape of filters, specifically the roll-off parameter of root raised cosine filters, affects excess noise in Gaussian modulated continuous variable quantum key distribution, finding minimal impact.

Contribution

It provides the first detailed analysis of filter shape effects on excess noise in CV-QKD systems with Gaussian modulation.

Findings

Roll-off parameter has negligible impact on excess noise performance.

Gaussian modulation remains secure regardless of filter shape.

Simulation results support robustness of CV-QKD to filter shape variations.

Abstract

An attractive implementation for quantum cryptography is the continuous variable variation, as it relies on standard telecommunication components. Modulating the quantum signal using a Gaussian format is attractive since it has been proven to be secure. This work investigates the effect of the roll-off of a root raised cosine pulse shaping and matched filter on the excess noise performance of a Gaussian modulated quantum key distribution system in a simulated back to back configuration. Contrary to intuition, it is found that the roll-off parameter does not significantly impact the performance of the system.