# Spectrally pure single photons at telecommunications wavelengths using commercial birefringent optical fiber

## TL;DR

This paper presents a cost-effective, fiber-based method for generating spectrally pure single photons at telecom wavelengths, with high purity and efficiency, suitable for scalable quantum optics applications.

## Contribution

It demonstrates a tunable, high-purity heralded single photon source using commercial birefringent fiber, and shows potential for creating multiple identical sources.

## Key findings

- Achieved 85% purity and 30% heralding efficiency.
- Confirmed fiber homogeneity over 45 centimeters.
- Potential to realize four identical sources.

## Abstract

We report a bright and tunable source of spectrally pure heralded single photons in the telecom O-Band, based on cross-polarized four wave mixing in a commercial birefringent optical fiber. The source can achieve a purity of 85%, heralding efficiency of 30% and high coincidences to accidentals ratio of 108. Furthermore, the possibility of building multiple identical sources is explored. Through the measurements of joint spectral intensities, we find that the fiber is homogeneous over atleast 45 centimeters and can potentially realize 4 identical sources. This paves the way for a cost-effective fiber-optic approach to implement multi-photon quantum optics experiments.