Spontaneous Brillouin scattering optical time domain reflectometer based on superconductive nanowire single-proton detector

Abstract

The invention discloses a spontaneous Brillouin scattering optical time domain reflectometer (BOTDR) based on a superconductive nanowire single-proton detector, which is characterized in that an optical pulse emitted by an optical pulse generating unit is coupled to a sensing optical fiber through a circulator, backward scattered light scattered from the sensing optical fiber is subjected to filtration of rayleigh scattering light through an optical filter unit to obtain Brillouin scattering light, a back scattering light signal is detected by the superconductive nanowire single-proton detector, an electric signal output from the superconductive nanowire single-proton detector is acquired and processed by a data acquiring and processing unit, and finally, a result is obtained through a certain demodulation relation. Compared with the traditional BOTDR, the BOTDR provided by the invention is used for carrying out data acquisition and processing by adopting the noise equivalent power (NEP) low/no-bandwidth-limit superconductive nanowire single-proton detector as a detection unit and adopting a single-proton counting technology.

Description

technical field [0001] The invention relates to a self-Brillouin scattered light time-domain reflectometer based on a superconducting nanowire single-photon detector, which is mainly used in the technical field of optical fiber sensor networks. Background technique [0002] In the current fully distributed optical fiber sensing technology, the fully distributed optical fiber sensing technology based on Brillouin scattering can realize long-distance continuous distributed measurement of temperature and strain in optical fibers, and can be applied to large buildings, highways, tunnels The monitoring and measurement of the health status of bridges, dams, communication cables, oil and gas pipelines, etc. has broad application prospects. Compared with other distributed optical fiber sensors, BOTDR based on self-published scattered optical time domain reflectometer has the advantages of single-ended sensing measurement and simultaneous sensing of temperature and strain. Brillouin...

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Problems solved by technology

For BOTDR, although it has the advantage of convenient single-ended measurement, due to the weak intensity of the spontaneous Brillouin scattered light, the signal-to-noise ratio of the traditional detector measurement is low, and the detection is difficult

The spatial resolution of the BOTDR system is limited by the detection pulse width and the bandwidth of the detector. To improve the spatial resolution, it is necessary to reduce the detection pulse width and increase the bandwidth of the detector. The wider the bandwidth of the analog detector, the higher the equivalent noise power value. Larger, the greater the minimum power that can be detected, so the spatial resolution of the system and the resolution of temperature and strain are difficult to improve at the same time

[0003] Because the traditional Brillouin scattered optical time domain reflectometer (BOTDR) uses an analog detector, it is limited by the equivalent noise power (NEP) and bandwidth of the analog detector. The detection capability is limited, so it is difficult for the traditional analog detector-based BOTDR system to achieve the measurement of large dynamic range, high spatial resolution and high strain / temperature measurement accuracy at the same time

[0004] At present, foreign BOTDR systems using analog detectors have commercial products. These products use coherent detection detection methods, and there are also some related patent materials, but no patent materials have been found that apply superconducting nanowire single photon detectors to BOTDR systems. and literature

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