# Luminescence in germania-silica fibers in 1-2 {\mu}m region

## TL;DR

This study investigates the luminescence properties of high-germanium germania-silica fibers in the 1-2 μm range, revealing challenges for photon triplet detection due to high luminescence levels.

## Contribution

It provides an analysis of the luminescence origins in germania-silica fibers and evaluates methods to reduce it for quantum optics applications.

## Key findings

- High luminescence levels hinder photon triplet observation.
- Hydrogen saturation reduces luminescence but remains insufficient.
- Luminescence originates from specific defect centers in fibers.

## Abstract

We analyze the origins of the luminescence in germania-silica fibers with high germanium concentration (about 30 mol. % GeO2) in the region 1-2 {\mu}m with a laser pump at the wavelength 532 nm. We show that such fibers demonstrate the high level of luminescence which unlikely allows the observation of photon triplets, generated in a third-order spontaneous parametric down-conversion process in such fibers. The only efficient approach to the luminescence reduction is the hydrogen saturation of fiber samples, however, even in this case the level of residual luminescence is still too high for three-photon registration.