A complete characterisation of the heralded noiseless amplification of photons

TL;DR

This paper provides a comprehensive characterization of a heralded noiseless photon amplifier at telecom wavelengths, demonstrating its capability to overcome significant transmission losses and its suitability for device-independent quantum key distribution over practical distances.

Contribution

It presents the first full characterization of a heralded noiseless photon amplifier, testing its limits and potential for device-independent quantum key distribution.

Findings

Achieved a gain >100 in the photon amplifier

Demonstrated heralding probability >83%

Overcame losses equivalent to 20 km of telecom fiber

Abstract

Heralded noiseless amplifcation of photons has recently been shown to provide a means to overcome losses in complex quantum communication tasks. In particular, to overcome transmission losses that could allow for the violation of a Bell inequality free from the detection loophole, for Device Independent Quantum Key Distribution (DI-QKD). Several implementations of a heralded photon amplifier have been proposed and the first proof of principle experiments realised. Here we present the first full characterisation of such a device to test its functional limits and potential for DI-QKD. This device is tested at telecom wavelengths and is shown to be capable of overcoming losses corresponding to a transmission through $20\, \rm km$ of single mode telecom fibre. We demonstrate heralded photon amplifier with a gain $>100$ and a heralding probability $>83 % $, required by DI-QKD protocols that use the Clauser-Horne-Shimony-Holt (CHSH) inequality. The heralded photon amplifier clearly represents a key technology for the realisation of DI-QKD in the real world and over typical network distances.