Distributed temperature sensing optical fiber

Abstract

The invention relates to a temperature sensing optical fiber applicable to a distributed temperature measuring system which adopts a Raman scattering principle and an optical time domain reflecting technology. The temperature sensing optical fiber comprises a core layer, a covering layer and a resin coating layer. The temperature sensing optical fiber is characterized in that: the diameter R1 of the core layer is 20 to 25 mu m; the refractive index profile of the core layer is in parabolic distribution; the maximum relative refractive index difference delta 1max is 3.3 to 4 percent; the covering layer is divided into three parts, namely an internal covering layer, a recessed covering layer and an external covering layer; the thickness W2 of the internal covering layer is 0 to 8 mu m, and the relative refractive index difference delta 2 is -0.05 to 0.05 percent; the thickness W3 of the recessed covering layer is 2 to 10 mu m, and the relative refractive index difference delta 3 is -0.10 to -0.25 percent; the radius R4 of the external coating layer is 40 to 45 mu m, and the relative refractive index difference delta 4 is -0.05 to 0.05 percent; and the external diameter R5 of the resin coating layer is 80 to 85 mu m. By adoption of the temperature sensing optical fiber, the temperature detection capacity and environment stability of the system can be improved, and the design difficulty in a detection laser pulse transmission part at the front end of a temperature sensing system and an optical signal detection amplifying part and a data processing part at the rear end of the temperature sensing system is reduced.

Description

technical field [0001] The invention relates to the field of optoelectronic technology and optical fiber manufacturing, in particular to a structural design of a temperature sensing optical fiber suitable for a distributed temperature measurement system based on the combination of Raman scattering principle and optical time domain reflection technology. Background technique [0002] The distributed optical fiber temperature measurement system integrates the principle of Raman scattering and optical time domain reflection technology, and collects the anti-Stokes light in the backward spontaneous Raman scattering carrying temperature information in the optical fiber as the signal channel, and at the same time collects the Stokes The Sri Lankan light or Rayleigh scattered light is used as a contrast channel, and the temperature field distribution along the optical fiber is restored through data processing after photoelectric conversion and analog-to-digital conversion. The key ...

AI Technical Summary

Problems solved by technology

The problems of using these optical fibers in the above-mentioned distributed optical fiber temperature measurement system are: the numerical aperture is small, and the capture ability of spontaneous Raman scattered light is not strong (GI62.5, GI50); the effective cross-sectional area is small, and the SRS power threshold is low (DCF); uneven attenuation increases in high humidity and hydrogen environments

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