Figure 1
From: Superconducting nanowire single-photon detectors integrated with tantalum pentoxide waveguides
(a) Nanophotonic circuit for characterization of the SNSPD. Two grating couplers are used for the alignment and calibration of the chip inside the cryostat, with input power port Pin and output power port Pout. A multi-mode interference device serves as an optical power splitter of the incoming light. (b) Scanning electron micrograph (false color) of a fabricated Ta2O5 SNSPD device. The length of the nanowire, \(l_{\text{nw}}\), is equal to approximately twice the detector length, \(l_{\det}\). (c) Illustration of a supported TE00 mode inside the tantalum pentoxide waveguide on an insulating silicon dioxide on silicon substrate with the niobium titanium nitride nanowire and hydrogen silsesquioxane resist on-top (simulated using the finite element method). The gap between the NbTiN nanowires is 150 nm.
