On-chip integration of superconducting nanowire single-photon detectors and reconfigurable optical circuits in lithium-niobate-on-insulator waveguides

Lomonte E; Wolff MA; Beutel F; Ferrari S; Schuck C; Pernice WHP; Lenzini F

Abstract

Lithium-niobate-on-insulator (LNOI) is emerging as a promising platform for integrated quantum photonic technologies because of its high second-order optical nonlinearity, compact footprint, and low propagation loss in a broad wavelength range. Importantly, LNOI allows for creating electro-optically tunable circuits that can be efficiently operated at cryogenic temperature. Their integration with superconducting nanowire single-photon detectors (SNSPDS) paves the way for realizing scalable photonic devices for fast manipulation and detection of quantum states of light. Here we report the monolithic integration of these two key components in a low loss (0.2 dB/cm) LNOI waveguide network. As an experimental showcase of our technology, we demonstrate the combined operation of an electrically tunable Mach Zehnder interferometer–an essential building block for the realization of reconfigurable optical networks-and two waveguide-integrated SNSPDs at its outputs. We show static reconfigurability of our system with a bias-drift free operation over a time of 12 hours, as well as high-speed modulation at frequencies up to 1 GHz.