Multimode Fiber Coupled Superconducting Nanowire Transition Edge Sensor for Detection of Single-Photon at Optical and Near-Infrared Wave Lengths

We report the development of the multimode fiber-coupled superconducting nanowire transition edge sensor with high system detection efficiency at optical and near-infrared wavelength. The SNTES consists of an absorber, a sensitive thermometer, and a weak thermal link to a cold bath, For a SNTES optimized to detect single photons, the temperature change caused by the absorption of a single photo is read out by the thermometer, and the system resets by cooling through the thermal link. The graded index (GRIN) lenses were spliced to the end of the multi mode fiber with a 50 µm diameter core, and the incident light spot diameter was focused to approximately 20 µm at the active area, which is 28 µm diameter, allowing a good optical coupling. We have achieved a nominal coupling efficiency of 91 % and system efficiency of 76 % by the SNTES at 1310 nm -1350 nm. The developed practical SNTES presented in this paper could open a new frontier for a wide range of applications at optical and infrared wavelength. Copyright © 2015 IFSA Publishing, S. L.