title: A monolithically integrated polarization entangled photon pair source on a silicon chip.
abstract: Integrated photonic circuits are one of the most promising platforms for large-scale photonic quantum information systems due to their small physical size and stable interferometers with near-perfect lateral-mode overlaps. Since many quantum information protocols are based on qubits defined by the polarization of photons, we must develop integrated building blocks to generate, manipulate, and measure the polarization-encoded quantum state on a chip. The generation unit is particularly important. Here we show the first integrated polarization-entangled photon pair source on a chip. We have implemented the source as a simple and stable silicon-on-insulator photonic circuit that generates an entangled state with 91 ± 2% fidelity. The source is equipped with versatile interfaces for silica-on-silicon or other types of waveguide platforms that accommodate the polarization manipulation and projection devices as well as pump light sources. Therefore, we are ready for the full-scale implementation of photonic quantum information systems on a chip.
authors.affiliation: NTT Basic Research Laboratories, NTT Corporation, Atsugi, Kanagawa, Japan. m.nobuyuki@lab.ntt.co.jp
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Matsuda
authors.forename: Hanna
authors.initials: H
authors.lastname: Le Jeannic
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fukuda
authors.forename: Tai
authors.initials: T
authors.lastname: Tsuchizawa
authors.forename: William John
authors.initials: WJ
authors.lastname: Munro
authors.forename: Kaoru
authors.initials: K
authors.lastname: Shimizu
authors.forename: Koji
authors.initials: K
authors.lastname: Yamada
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Tokura
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takesue