A fiber f-p composite cavity type high temperature strain sensor

Abstract

The invention discloses an optical fiber F-P composite cavity type high temperature strain sensor. The optical fiber F-P composite cavity type high temperature strain sensor comprises a first single mode fiber, a second single mode fiber, a multimode fiber and a capillary glass tube with openings at both ends; the material of the fiber is selected from molten SiO2; one flat end surface of the first single mode fiber is plated with a dielectric reflective film having a fixed reflectance, and the coated end surface of the first single mode fiber is fused with an uncoated flat end surface of thesecond single mode fiber; an uncoated flat end surface of the multimode fiber and an uncoated flat end surface of first single mode fiber are inserted into a cavity of the capillary glass tube throughthe openings at both ends of the capillary glass tube respectively; two end surfaces inserted into the cavity, of the multimode fiber and the first single mode fiber are aligned with each other in parallel and do not contact each other; the multimode fiber and the first single mode fiber are glued to the capillary glass tube; and the other end surface of the multimode fiber is subjected to laserdrilling. The invention can realize simultaneous monitoring of temperature and large-range strain in an ultra-high temperature environment.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensing, in particular to an optical fiber F-P composite cavity type high temperature strain sensor. Background technique [0002] With the development of optoelectronic technologies such as optical fiber preparation technology and laser technology, optical communication technology and optical fiber sensing technology using optical fiber as the information transmission medium have developed rapidly, and have been widely used in aerospace, petrochemical, security monitoring and many other fields. In optical fiber sensing technology, the optical fiber can be used not only as a medium for transmitting optical information, but also as a sensitive detection unit for detecting changes in external physical quantities through special structural design, process processing, and material doping. sensing unit. As an important branch of fiber optic sensors, fiber optic F-P sensors have all the advantage...

AI Technical Summary

Problems solved by technology

However, the measurement rate of the fiber Bragg grating (FBG) sensor to the ambient temperature is slower than the rate of change of the ambient temperature or the temperature of the substrate where the sensor is installed, so this method has a large error in measuring the actual stress, and the ordinary fiber Bragg grating (FBG) sensor It can only withstand the temperature environment of 200°C for a short period of time, which limits its application in ultra-high temperature environments

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