Effect of Loss on Multiplexed Single-Photon Sources

TL;DR

This paper provides a theoretical framework for understanding how loss impacts the performance of multiplexed single-photon sources, demonstrating potential for high-photon-number generation with low multi-photon contamination using realistic components.

Contribution

It introduces a comprehensive model for lossy multiplexed single-photon sources and evaluates their performance, guiding future experimental design and optimization.

Findings

High-efficiency, low-loss switches enable generation of 20-40 photon states.

Losses of 0.2-0.4 dB in switches still allow effective multi-photon state production.

Multiplexed sources can achieve low multi-photon contamination with realistic detector efficiencies.

Abstract

An on-demand single-photon source is a key requirement for scaling many optical quantum technologies. A promising approach to realize an on-demand single-photon source is to multiplex an array of heralded single-photon sources using an active optical switching network. However, the performance of multiplexed sources is degraded by photon loss in the optical components and the non-unit detection efficiency of the heralding detectors. We provide a theoretical description of a general multiplexed single-photon source with lossy components and derive expressions for the output probabilities of single-photon emission and multi-photon contamination. We apply these expressions to three specific multiplexing source architectures and consider their tradeoffs in design and performance. To assess the effect of lossy components on near- and long-term experimental goals, we simulate the multiplexed sources when used for many-photon state generation under various amounts of component loss. We find that with a multiplexed source composed of switches with ~0.2-0.4 dB loss and high efficiency number-resolving detectors, a single-photon source capable of efficiently producing 20-40 photon states with low multi-photon contamination is possible, offering the possibility of unlocking new classes of experiments and technologies.