32 × 32 NbN SNSPD array based on thermally coupled row-column multiplexing architecture

We report a superconducting nanowire single-photon detector (SNSPD) array aiming for a near-infrared 1550-nm wavelength that consists of 32 × 32 nanowire pixels and an area of 0.96 mm × 0.96 mm. Unlike most reported large-scale SNSPD arrays with amorphous films, NbN superconducting nanowires are employed in our array, which allows the detector operation at 2.3 K provided by a compact two-stage Gifford–McMahon cryocooler. Thermally coupled row–column multiplexing is employed in our arrays to avoid current redistribution and loss of electrical signal occurring in the electrically coupled row–column architecture. The fabricated detector array shows a pixel yield of 94% and maximal intrinsic efficiencies of 77% and 96% at 1550 nm and 405 nm, respectively. The timing jitter and the thermal coupling probability are also investigated.