title: Ultralow loss, high Q, four port resonant couplers for quantum optics and photonics.
abstract: We demonstrate a low-loss, optical four port resonant coupler (add-drop geometry), using ultrahigh Q (>10(8)) toroidal microcavities. Different regimes of operation are investigated by variation of coupling between resonator and fiber taper waveguides. As a result, waveguide-to-waveguide power transfer efficiency of 93% (0.3 dB loss) and nonresonant insertion loss of 0.02% (<0.001 dB) for narrow bandwidth (57 MHz) four port couplers are achieved in this work. The combination of low-loss, fiber compatibility, and wafer-scale design would be suitable for a variety of applications ranging from quantum optics to photonic networks.
authors.affiliation: Thomas J. Watson Laboratory of Applied Physics, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: H
authors.initials: H
authors.lastname: Rokhsari
authors.forename: K J
authors.initials: KJ
authors.lastname: Vahala