Pilot-assisted intradyne reception for high-speed continuous-variable quantum key distribution with true local oscillator

TL;DR

This paper introduces a pilot-assisted intradyne detection method for high-speed continuous-variable quantum key distribution using a true local oscillator, achieving precise phase matching and low excess noise at high symbol rates.

Contribution

It proposes a novel pilot-assisted coherent detection scheme with optical phase locking for CV-QKD, enabling high-speed operation with low excess noise.

Findings

Successful experimental validation at 250 Mbaud

Achieved low excess noise levels

Demonstrated high symbol rate compatibility

Abstract

We present a pilot-assisted coherent intradyne reception methodology for CV-QKD with true local oscillator. An optically phase-locked reference tone, prepared using carrier-suppressed optical single-sideband modulation, is multiplexed in polarisation and frequency to the 250 Mbaud quantum signal in order to provide optical frequency- and phase matching between quantum signal and local oscillator. Our concept allows for high symbol rates and can be operated at an extremely low excess-noise level, as validated by experimental measurements.