Hole Burning Spectroscopy of Erbium-doped Optical Fibre for Applications in Quantum Networks
Creators: name: Shafiei Alavijeh, Sara
Publisher: name: Science
Year: 2022
Subjects: subject: Erbium-doped Optical Fiber
subject: Erbium-doped Fiber
subject: EDF
subject: Erbium-doped Fiber Spectroscopy
subject: Hole-burning Spectroscopy
subject: Persistent Spectral Hole Burning
subject: PSHB
subject: Fibre-based Quantum Information Processing
subject: Quantum Networks
subject: Fibre-based Quantum Network
subject: Quantum Communication
subject: Fibre-based Quantum Communication
subject: Long-distance Quantum Communication
subject: Light-matter Interface
subject: Fibre Light-matter Interface
subject: Erbium-doped
subject: Rare-earth Ion Spectroscopy
subject: Sub-Kelvin Temperature
subject: Sub-Kelvin Temperature Spectroscopy
subject: Sub-Kelvin Temperature Spectroscopic properties
subject: Sub-Kelvin Temperature properties of glass
subject: Disordered material
subject: Disordered Material Spectroscopy
subject: Low-temperature spectroscopic properties
subject: Amorphous
subject: Silica fibre
subject: Spin-lifetime
subject: Spin Spectroscopy
subject: Spin-level Spectroscopy
subject: Telecom-band
subject: Telecommunication wavelength
subject: Fibre-based Quantum Internet
subject: low-temperature properties of erbium-doped solids
subject: long lifetime of the erbium spin
subject: Erbium spins
subject: large-scale quantum networks
subject: Erbium electronic spin state
subject: broadband quantum memory
subject: Telecom quantum memory
subject: multi-mode storage
subject: multiplexed quantum information processing
subject: 7 mK
subject: 7 milikelvin
subject: spectral tailoring
subject: Information Science
subject: Physics
subject: Physics--Atomic
subject: Optics
subject: Applied Sciences

description: This thesis provides a spectroscopic study on the relevant properties of Erbium-doped Optical Fiber (EDF) for its application as a light-matter interface in large-scale quantum networks, which is the frontier of research in Quantum Information Processing (QIP). The unique position of erbium as a rare-earth ion with optical transitions in 1.5 μm, the telecommunication band, has long attracted researchers towards studying the low-temperature properties of erbium-doped solids for QIP, and EDF is particularly attractive for the possibility of direct integration with fiber-based channels. Here, we experimentally investigate this system at temperatures as low as 7 mK, and report the observation of an 8-hour long lifetime of the erbium spin at an optimal magnetic field of 0.05 Tesla. This record-long lifetime corresponds to three orders of magnitude extension as compared to previously-reported results at 650 mK temperature. We perform a full set of spin-lifetime measurements, using Persistent Spectral Hole Burning (PSHB), over a wide range of temperatures and magnetic fields, and identify the optimal points for efficient spectral tailoring of the EDF's inhomogeneously-broadened absorption profile over telecom band. We demonstrate 92.5\% efficiency in the optical pumping of erbium ions into a single electronic spin state, enabling efficient broadband quantum memory, and create 3 MHz-wide spectral features, allowing for 10^6 number of addressable frequency modes for multiplexed processing and multi-mode storage in the frequency domain. We use our experimental data to reproduce the temperature and magnetic field dependencies of a spin-lifetime model adapted to amorphous (highly-disordered) host environment, which validates the legitimacy of our new findings. Furthermore, we are able to use this analysis to obtain information on what limits the lifetimes for certain ions, which provides a tool for enhancing the light-matter interactions in EDF and maximizing the functional time for spectral tailoring. In addition to uncovering a entirely-new technological outlook for EDF, our study shines light on the fundamental physics of amorphous-specific interactions at low temperatures, which, as opposed to crystals, still lacks theoretical explanations.