Analysis of Spin Lifetime and Optical Coherence Time Mechanisms in Erbium-Doped Fiber (EDF)

Erbium-Doped fiber (EDF) is a promising element in quantum communications due to its unique optical transitions around 1.5 µm within the telecommunication c-band. This research explores the spin lifetime and optical coherence time mechanisms in EDF, with a particular focus on understanding the Two-Level System (TLS) interaction in varying magnetic fields and temperatures. A notable observation in our experimental data is an hour-long spin lifetime at temperatures down to 7 mK, hinting at possibilities for long-lived optical storage elements for fiber-optic communication. Utilizing Spectral Hole Burning measurements, we aim to refine the existing spin-lifetime model, as the new experimental data at these temperatures challenges the previous model outlined in Phys. Rev. B 92, 241111 (2015). Our approach seeks to clarify interactions leading to homogeneous line broadening and decoherence, aiming to enhance the optical coherence time mechanism. The compatibility of EDF with existing telecom infrastructure, coupled with its potential to advance the development of quantum memories and transducers within the EDF system, highlights its capability to propel the field of quantum communication forward.