High-sensitivity up-conversion single photon detection system

Abstract

The invention relates to a high-sensitivity up-conversion single photon detection system. The system comprises an adjustable attenuator for receiving pumping laser emitted by a laser device; an output end of the adjustable attenuator is connected with an input end of a beam splitter; the output end of the beam splitter is respectively connected with a power meter and a wavelength-division multiplexer which is used for receiving signal light to be coupled; the output end of the wavelength-division multiplexer is connected with the input end of a nonlinear waveguide; and a single photon detector is arranged at the output end of the nonlinear waveguide. In the invention, the pumping laser enters into the nonlinear waveguide with the signal light by wavelength-division multiplexing, and the nonlinear waveguide can eliminate Raman noise to a great extent. In the nonlinear waveguide, the signal light can be converted up into visible light, and the up converted visible photons are collected in the single photo detector for detection.

Description

technical field [0001] The invention relates to a single-photon detection system, in particular to a high-sensitivity up-conversion single-photon detection system. [0002] Background technique [0003] Single photon detector is the main tool for ultra-weak light detection, and has a wide range of applications in many fields. Single photon detectors in the communication band are the core devices in the fields of quantum communication, quantum cryptography, and optical fiber time domain reflectometer. The commonly used single photon detectors in the communication band include superconducting detectors, indium gallium arsenic avalanche diode single photon detectors and There are three types of upconversion detectors. [0004] Superconducting detectors have the advantage of low noise, but they require a bulky, cumbersome and expensive ultra-low temperature cooling system, which is difficult to use in practical applications. In addition, the detection efficiency of commercial ...

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Problems solved by technology

[0004] Superconducting detectors have the advantage of low noise, but they require a bulky, cumbersome and expensive ultra-low temperature cooling system, which is difficult to use in practical applications. In addition, the detection efficiency of commercial superconducting detectors is low, which also limits its application

The commercial InGaAs avalanche diode single photon detector has the advantages of small size, low cost, and can be integrated. However, it also has the disadvantage of low detection efficiency. At the same time, its significant post-pulse effect also brings high noise, making Its application is greatly discounted

The up-conversion detector uses a nonlinear waveguide to change the frequency of the light in the communication band, up-converts it into visible light, and uses a silicon avalanche diode single-photon detector for detection. It has the advantages of high detection efficiency and room temperature operation. The Raman noise generated by the low-frequency pump laser in the process is too high, which seriously limits the performance of the detector and the application system

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