High efficiency, low-noise superconducting nanowire singlephoton detectors integrated with nanophotonic circuits

High detection efficiency, low dark count rate and accurate timing resolution are the most desired features of a single photon detector. For quantum optical information processing it is furthermore highly desirable to integrate detectors and optical circuitry on one common and scalable platform. Here I will present how these requirements can be met with NbTiN nanowire superconducting single-photon detectors (SSPD) embedded in nano-photonic waveguides on a silicon chip. Employing a travelling wave design we realize high detection efficiency for single-photons both in the visible (80%) and in the telecom band (70%). By engineering the detector and waveguide dimensions at the nanoscale we furthermore achieve nanosecond electrical output pulses with 50 ps timing jitter and milli-Hz dark count rates, resulting in a noise equivalent power at the 10-20 W/(Hz1/2) level. To illustrate the attractive low-noise performance of our detector we perform photon-counting optical time domain reflectometry (OTDR) over 263 km of standard telecom fiber. The integration of such low-noise, high-efficiency superconducting single-photon detectors with low-loss optical waveguide devices on a silicon chip is an ideal match for scalable quantum photonic circuitry.