Realization of a multi-output quantum pulse gate for decoding high-dimensional temporal modes of single-photon states

TL;DR

This paper demonstrates a high-fidelity, multi-output quantum pulse gate capable of decoding five-dimensional temporal modes of single photons, advancing high-dimensional quantum communication and key distribution.

Contribution

The work introduces a novel multi-output quantum pulse gate device and experimentally demonstrates its capability for high-dimensional TM decoding with high fidelity.

Findings

Achieved 0.96 fidelity in demultiplexing five-dimensional TMs

Developed a proof-of-principle decoder for high-dimensional quantum key distribution

Confirmed high-quality operation with 0.98 fidelity in state tomography

Abstract

Temporal modes (TMs) of photons provide an appealing high-dimensional encoding basis for quantum information. While techniques to generate TM states have been established, high-dimensional decoding of single-photon TMs remains an open challenge. In this work, we experimentally demonstrate demultiplexing of five-dimensional TMs of single photons with an average fidelity of 0.96 $\pm$ 0.01, characterized via measurement tomography. This is achieved using a newly developed device, the multi-output quantum pulse gate (mQPG). We demonstrate a proof-of-principle complete decoder based on the mQPG that operates on any basis from a set of 6 five-dimensional MUBs and is therefore suitable as a receiver for high-dimensional quantum key distribution. Furthermore, we confirm the high-quality operation of the mQPG by performing resource-efficient state tomography with an average fidelity of 0.98 $\pm$ 0.02.