Optical Quantum Memory and Signal Processing Using a Rare-earth-ion-doped Waveguide
Abstract
Advanced applications of quantum information science, such as long-distance quantum communication based on quantum repeaters, require photons to be interfaced with different devices. These devices, such as single photon detectors, quantum memories, quantum signal processors, and linear optical elements, may be integrated on a single chip to enable efficient, robust and scalable implementations. With aim of constructing a quantum repeater, and towards realizing integrated optical quantum memories and signal processors in general, we experimentally develop quantum light-matter interfaces using a cryogenically-cooled rare-earth-ion-doped waveguide, namely thulium-doped lithium niobate (Tm3+:LiNbO3). As the basis for our work, we describe a quantum repeater architecture that uses spectral multiplexing and quantum memories that operate with a fixed storage time. Our repeater architecture promises efficient operation, is compatible with the properties of cryogenically-cooled rare-earth-ion-doped crystals, and simplifies the demands of quantum memories compared to other architectures. To demonstrate the feasibility of our repeater design, we utilize our light-matter interface as a quantum memory to perform several experimental demonstrations. These include high-fidelity storage and retrieval of 26 spectrally-multiplexed quantum bits encoded into single-photon-level laser pulses, high-fidelity storage and retrieval of single and entangled photons derived from a photon-pair source, and high-visibility two-photon interference between weak laser pulses that are stored in one or two, separate, quantum memories. The unique properties of our light-matter interface allow us to demonstrate additional protocols that further highlight its promise for integrated quantum signal processing. By combining our Tm3+:LiNbO3 waveguide with a LiNbO3 waveguide phase modulator, we demonstrate operations such as sequencing, filtering, interference, and compression of laser pulses attenuated to the single-photon level. In another experiment, we measure the cross-phase modulation between strong pulses, by which we demonstrate photon-photon interactions that point towards non-destructive measurements of quantum bits. Since the performance of all aforementioned protocols, and future light-matter applications, hinge on the basic spectroscopic properties of our waveguide, we measure these properties at temperatures as low as 800 millikelvin. Our findings, discussed over several attached publications, usher the development of integrated quantum memories and processors for multi-component optical quantum information applications such as repeaters and networks.
Description
Keywords
Physics--Atomic, Optics
Citation
Sinclair, N. (2016). Optical Quantum Memory and Signal Processing Using a Rare-earth-ion-doped Waveguide (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/27205