Free-space-coupled superconducting nanowire single-photon detectors for infrared optical communications
Author(s)Bellei, Francesco; Cartwright, Alyssa P.; McCaughan, Adam N; Dane, Andrew E.; Najafi, Faraz; Zhao, Qingyuan; Berggren, Karl K; ... Show more Show less
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This paper describes the construction of a cryostat and an optical system with a free-space coupling efficiency of 56.5% ± 3.4% to a superconducting nanowire single-photon detector (SNSPD) for infrared quantum communication and spectrum analysis. A 1K pot decreases the base temperature to T= 1.7 K from the 2.9 K reached by the cold head cooled by a pulse-tube cryocooler. The minimum spot size coupled to the detector chip was 6.6 ± 0.11 μm starting from a fiber source at wavelength, λ = 1.55 μm. We demonstrated photon counting on a detector with an 8 × 7.3 μm² area. We measured a dark count rate of 95 ± 3.35 kcps and a system detection efficiency of 1.64% ± 0.13%. We explain the key steps that are required to improve further the coupling efficiency.
DepartmentMassachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Optical Society of America
Bellei, Francesco; Cartwright, Alyssa P.; McCaughan, Adam N et al. “Free-Space-Coupled Superconducting Nanowire Single-Photon Detectors for Infrared Optical Communications.” Optics Express 24, 4 (February 2016): 3248-3257. © 2016 Optical Society of America