Parasitic erbium photoluminescence in commercial telecom fiber optical components

TL;DR

This study reveals the presence of parasitic erbium photoluminescence in commercial telecom fiber components, highlighting challenges in noise mitigation for quantum communication applications due to trace erbium impurities.

Contribution

It provides the first characterization of erbium-related noise in various commercial telecom fiber components using tunable laser spectroscopy.

Findings

Trace erbium detected in all tested devices

Long erbium lifetime complicates noise mitigation

Implication for higher purity optical crystals needed

Abstract

Noiseless optical components are critical for applications ranging from metrology to quantum communication. Here we characterize several commercial telecom C-band fiber components for parasitic noise using a tunable laser. We observe the spectral signature of trace concentrations of erbium in all devices from the underlying optical crystals including YVO4, LiNbO3, TeO2 and AMTIR glass. Due to the long erbium lifetime, these signals are challenging to mitigate at the single photon level in the telecom range, and suggests the need for higher purity optical crystals.