# Large-Alphabet Encoding Schemes for Floodlight Quantum Key Distribution

## TL;DR

This paper demonstrates that using 32-ary phase-shift keying in floodlight quantum key distribution significantly doubles the secret-key rate compared to binary phase-shift keying, enhancing secure communication speeds.

## Contribution

The study introduces a novel encoding scheme with 32-ary PSK for FL-QKD, achieving higher secret-key rates over metropolitan distances.

## Key findings

- 32-ary PSK doubles the SKR compared to BPSK in FL-QKD
- Higher alphabet encoding improves secure communication rates
- Experimental validation confirms theoretical predictions

## Abstract

Floodlight quantum key distribution (FL-QKD) uses binary phase-shift keying (BPSK) of multiple optical modes to achieve Gbps secret-key rates (SKRs) at metropolitan-area distances. We show that FL-QKD's SKR can be doubled by using 32-ary PSK.