Optical decoherence and spectral diffusion in an erbium-doped silica glass fiber featuring long-lived spin sublevels

TL;DR

This study investigates the decoherence mechanisms in erbium-doped silica glass fibers at cryogenic temperatures, revealing conditions for narrow linewidths and long-lived spin states relevant for quantum communication.

Contribution

It provides a detailed analysis of spectral diffusion and decoherence in erbium-doped glass fibers, introducing a model that explains experimental linewidths and coherence properties.

Findings

Narrow linewidths (~1 MHz) achieved at 0.6 K and 0.05 T

Spectral diffusion influenced by magnetic interactions and dynamic disorder

Model successfully describes linewidth dependence on field, temperature, and time

Abstract

Understanding decoherence in cryogenically-cooled rare-earth-ion doped glass fibers is of fundamental interest and a prerequisite for applications of these material in quantum information applications. Here we study the coherence properties in a weakly doped erbium silica glass fiber motivated by our recent observation of efficient and long-lived Zeeman sublevel storage in this material and by its potential for applications at telecommunication wavelengths. We analyze photon echo decays as well as the potential mechanisms of spectral diffusion that can be caused by coupling with dynamic disorder modes that are characteristic for glassy hosts, and by the magnetic dipole-dipole interactions between $Er^{3+}$ ions. We also investigate the effective linewidth as a function of magnetic field, temperature and time, and then present a model that describes these experimental observations. We highlight that the operating conditions (0.6 K and 0.05 T) at which we previously observed efficient spectral hole burning coincide with those for narrow linewidths (1 MHz) { an important property for applications that has not been reported before for a rare-earth-ion doped glass.