Spectral correlation in down-converted photon pairs at telecom wavelength

TL;DR

This paper analyzes the spectral correlation properties of BBO crystal-based photon pair sources at telecom wavelengths, providing insights for optimizing their spectral features for long-distance quantum communication.

Contribution

It offers an analytical and numerical analysis of a BBO-based photon pair source, enabling full control of spectral correlation with optimal brightness.

Findings

Spectral correlation can be fully controlled in the source.

The analysis enables optimization for long-distance quantum communication.

The source achieves high brightness while controlling spectral properties.

Abstract

Sources of photon pairs based on the spontaneous parametric down conversion process are commonly used for long distance quantum communication. The key feature for improving the range of transmission is engineering their spectral properties. Following two experimental papers [Opt. Lett., 38, 697 (2013)] and [Opt. Lett., 39, 1481 (2014)] we analytically and numerically analyze the characteristics of a source. It is based on a $\beta$-barium borate (BBO) crystal cut for type II phase matching at the degenerated frequencies 755 nm $\rightarrow$ 1550 nm + 1550 nm. Our analysis shows a way for full control of spectral correlation within a fiber-coupled photon pair simultaneously with optimal brightness.