High-efficiency Bragg grating enhanced on-chip photon-number-resolving detectors

The recent trend towards integration of quantum optics experiments has produced a demand for on-chip single photon detectors with high quantum efficiencies. In previous work we demonstrated integrated photon number resolving detectors for use at telecommunications wavelengths [1], here we outline developments of this design which have enabled improvements in the quantum efficiency, permitting an on-chip detection efficiency of 92% to be obtained in the device of Fig. 1. ..

Experimental investigation of the detection mechanism in WSi nanowire superconducting single photon detectors

Quantum Matter and Optic

Integrated optical platform for photon-number resolving telecom-band detectors for photonic information processing

We report the development of the optical substrates for the demonstration of an integrated photon-number-resolving detector, operating in the telecom band at 1550 nm, employing an evanescently coupled design that allows it to be placed at arbitrary locations within a planar circuit. Up to five photons are resolved in the guided optical mode via absorption from the evanescent field into a tungsten transition-edge sensor. The detection efficiency is 7.2 ± 0.5%. The polarization sensitivity of the detector is also demonstrated

Determining the depairing current in superconducting nanowire single-photon detectors

We estimate the depairing current of superconducting nanowire single-photon detectors (SNSPDs) by studying the dependence of the nanowires' kinetic inductance on their bias current. The kinetic inductance is determined by measuring the resonance frequency of resonator-style nanowire coplanar waveguides both in transmission and reflection configurations. Bias current dependent shifts in the measured resonant frequency correspond to the change in the kinetic inductance, which can be compared with theoretical predictions. We demonstrate that the fast relaxation model described in the literature accurately matches our experimental data and provides a valuable tool for determination of the depairing current. Accurate measurement of the depairing current is critical for nanowire quality analysis, as well as modeling efforts aimed at understanding the detection mechanism in SNSPDs

UV-written silica waveguide devices for integrated quantum optics

We present details of the UV-written silica-on-silicon platform for integrated quantum optics with reference to recent results, and discuss the fabrication challenges involved in scaling to larger experiments