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Publication - Dr Krishna Coimbatore Balram

    Efficient fiber-coupled single-photon source based on quantum dots in a photonic-crystal waveguide


    Daveau, RS, Balram, KC, Pregnolato, T, Liu, J, Lee, EH, Song, JD, Verma, V, Mirin, R, Nam, SW, Midolo, L, Stobbe, S, Srinivasan, K & Lodahl, P, 2017, ‘Efficient fiber-coupled single-photon source based on quantum dots in a photonic-crystal waveguide’. Optica, vol 4., pp. 178-184


    Many photonic quantum information processing applications would benefit from a high brightness, fiber-coupled source of triggered single photons. Here, we present a fiber-coupled photonic-crystal waveguide (PCWG) singlephoton source relying on evanescent coupling of the light field from a tapered outcoupler to an optical fiber. A two-step approach is taken where the performance of the tapered outcoupler is recorded first on an independent device containing an on-chip reflector. Reflection measurements establish that the chip-to-fiber coupling efficiency exceeds 80%. The detailed characterization of a high-efficiency PCWG extended with a tapered outcoupling section is then performed. The corresponding overall single-photon source efficiency is 10.9%±2.3%, which quantifies the success probability to prepare an exciton in the quantum dot, couple it out as a photon in the waveguide, and subsequently transfer it to the fiber. The applied outcoupling method is robust, stable over time, and broadband over several tens of nanometers, which makes it a highly promising pathway to increase the efficiency and reliability of planar chip-based single-photon sources.

    Full details in the University publications repository