High quality entanglement distribution through telecommunication fiber using near-infrared non-degenerate photon pairs

TL;DR

This paper demonstrates high-quality entanglement distribution over 12 km of standard telecommunication fiber using near-infrared photon pairs around 810 nm, leveraging high-efficiency detectors and mature setups for practical quantum communication.

Contribution

It shows successful transmission of entangled photon pairs at 810 nm through standard fiber with high entanglement quality, suitable for campus quantum networks.

Findings

94.8% visibility of entanglement after 12 km fiber

Successful distribution of degenerate and non-degenerate photon pairs

Maintains polarization entanglement with high fidelity

Abstract

For practical quantum communications, the efficiency of the entire system (source, quantum channel and detectors) must be taken into account. In many urban environments, the quantum channel in the form of telecommunication optical fiber (confirming to ITU G.652D standards) are available, but the detectors in this range typically have low efficiency. We investigate the possibility that for campus-type communications, entangled photons prepared in the Near-Infrared Range (NIR) can be transmitted successfully while preserving polarization entanglement. We demonstrate the distribution of degenerate and non-degenerate entangled photon pairs of wavelength around 810 nm through standard telecommunication fiber. This technique benefits from the high efficiency of the NIR single photon detectors and the mature design of setups around 810 nm.. In this work, we obtain high quality entanglement (visibility is 94.8\% based on the raw data) after an overall distance of 12 km, corresponding to about -36 dB of fiber induced loss.