Ultrafast time-division demultiplexing of polarization-entangled photons

TL;DR

This paper demonstrates an ultrafast method for demultiplexing polarization-entangled photons using time-to-frequency conversion, significantly enhancing quantum communication rates by enabling detection on picosecond timescales.

Contribution

The authors introduce a novel technique for ultrafast demultiplexing of entangled photons via time-to-frequency conversion, preserving quantum correlations and compatible with existing detectors.

Findings

Converted 2.69 ps pulse train to 307 GHz frequency comb

Preserved polarization entanglement during demultiplexing

Enabled ultrafast quantum multiplexing with commercial detectors

Abstract

Maximizing the information transmission rate through quantum channels is essential for practical implementation of quantum communication. Time-division multiplexing is an approach for which the ultimate rate requires the ability to manipulate and detect single photons on ultrafast timescales while preserving their quantum correlations. Here we demonstrate the demultiplexing of a train of pulsed single photons using time-to-frequency conversion while preserving their polarization entanglement with a partner photon. Our technique converts a pulse train with 2.69 ps spacing to a frequency comb with 307 GHz spacing which may be resolved using diffraction techniques. Our work enables ultrafast multiplexing of quantum information with commercially available single-photon detectors.