Micro optical-mechanical-electrical device for distributed type optical fiber temperature sensor

Abstract

The invention discloses a micro optical-mechanical-electrical device for a distributed type optical fiber temperature sensor and belongs to the technical field of optical fiber sensing. The micro optical-mechanical-electrical device comprises a first collimator tail fiber, a second collimator tail fiber and a diffraction grating which are mounted in a shell, wherein a sensing optical fiber is externally connected with the second collimator tail fiber; a band-pass filter sheet with an anti-stokes optical wavelength and a band-pass filter sheet with a stokes optical wavelength are arranged on areflecting light path of a backward scattering light passing through the diffraction grating; a first self-focusing lens is arranged on a transmission light path of the band-pass filter sheet with the anti-stokes optical wavelength; a first avalanche photodiode is arranged at a focal point of the first self-focusing lens; a second self-focusing lens is arranged on the transmission light path of the band-pass filter sheet with the stokes optical wavelength; and a second avalanche photodiode is arranged at a focal point of the second self-focusing lens. An anti-stokes light and a stokes light are reliably separated by using the micro optical-mechanical-electrical device provided by the invention, so that the accurate temperature information is obtained and the temperature resolution of the system is increased.

Description

technical field [0001] The invention relates to a photoelectric device, in particular to a micro-opto-electromechanical device for a distributed optical fiber temperature sensor, belonging to the technical field of optical fiber sensing. Background technique [0002] Since J.P.Dakin and others successfully realized the distributed temperature measurement technology based on Raman scattering for the first time in 1985, people have carried out extensive research on various technologies for realizing distributed optical fiber temperature sensing. Sensing technology has been the most widely used in practice. Compared with traditional sensors, distributed optical fiber temperature sensors have many excellent advantages: using optical fiber itself as the sensing medium, temperature information of thousands of points distributed along the optical fiber can be obtained in one measurement, which realizes continuous distributed measurement and reduces the Measurement uncertainty; lon...

AI Technical Summary

Problems solved by technology

First of all, this wavelength division multiplexing device uses a 1X3 bidirectional coupler, which will introduce an additional loss of about 9.5dB (10log(1 / 9)=9.5dB), which greatly weakens the available anti-Stokes light and Stokes light intensity; Secondly, the isolation of the device is difficult to exceed 40dB, the reason is the same as above

[0007] If a conventional wavelength division multiplexing device is used in a distributed optical fiber temperature sensor, usually due to insufficient isolation, it will cause mutual crosstalk between anti-Stokes light and Stokes light, as well as interference of Rayleigh scattered light, so If not, it will be difficult to obtain accurate temperature information and high resolution. In severe cases, the temperature curve will be distorted and the system will not work properly.

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