A Design of Snspd Dark Count Reduction Based on Double-wire Structure

Abstract

The invention discloses a design for reducing SNSPD dark counts based on a double-wire structure. Two niobium nitride nanowires are intertwined without intersecting each other to form a double-wire structure superconducting nanowire single-photon detector SNSPD. The wire regulates the behavior of another nanowire, and adjusts the bias current close to the superconducting critical current; the optical signal is introduced into the photosensitive area of ​​the detector through the optical fiber, and two signals are output through the two nanowires, so that the distance between the two nanowires The dark counts are mutually excited, and the dark count signal is reduced by the voltage comparator and the XOR gate, and the photon response signal is retained; by using the unique performance of the double-wire structure SNSPD, the generation of the dark count of the detector can be effectively suppressed, and the process can be improved in the later stage to further improve The coupling efficiency of the SNSPD dark count is expected to completely suppress the dark count of the SNSPD system and greatly improve the signal-to-noise ratio of the detector.

Description

technical field [0001] The invention belongs to the technical field of superconducting single photon detection, and in particular relates to a dark count subtraction technology. Background technique [0002] Superconducting nanowire single photon detector (SNSPD) is a new type of photodetector for efficient, fast and accurate detection of single photons. The photosensitive part is a nanowire meander structure made of superconducting thin film materials. [0003] When the detector is working, it is biased at a position slightly lower than its superconducting critical current. When the nanowire absorbs photons, the superconducting state in the absorbing region is destroyed, resulting in a heat island. The heat island region grows with the assistance of current Joule heat. To a certain range, after the cooling of the nanowire itself and the substrate, the heat island disappears, and the nanowire returns to its initial state. [0004] The process of photon absorption by the det...

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Problems solved by technology

[0008] For background radiation dark counting, the commonly used method is to use fiber optic filter at low temperature to eliminate background radiation, but for intrinsic dark counting, there is no better general method so far.

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