Extrinsic Fabry Perot interferometer (EFPI) optical fiber sensor

Abstract

The invention discloses an extrinsic Fabry Perot interferometer (EFPI) optical fiber sensor and aims to solve the problems that the accuracy is low because a conventional EFPI optical fiber sensor is low in heat stability. The EFPI optical fiber sensor comprises a capillary glass tube, an incident optical fiber of which at least one part is positioned in the capillary glass tube, as well as a light ray transmitting end of which at least one part is positioned in the capillary glass tube and forms a gap with the incident optical fiber, wherein the thermal expansion coefficient ratio of the capillary glass tube to the light ray transmitting end is 0.25-0.99. According to the EFPI optical fiber sensor in the embodiment, the thermal expansion coefficient ratio of the capillary glass tube to the light ray transmitting end is 0.25-0.99, so that the heat expansion and cold contraction of the light ray transmitting end on the capillary glass tube are compensated, and overcompensation is avoided. Therefore, the EFPI optical fiber sensor has the advantages of low temperature sensitivity, accurate measurement result, simple structure and the like.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensing, in particular to an EFPI optical fiber sensor. Background technique [0002] like Figure 1-Figure 2 As shown, the EFPI (Extrinsic Fabry-Perot Interferometric) optical fiber sensor includes a capillary glass tube 1 , an incident optical fiber 21 partially inserted into the capillary glass tube, and a reflective optical fiber 22 . The incident optical fiber 21 and the reflective optical fiber 22 are arranged with a gap. The incident optical fiber 21 , the reflective optical fiber 22 and the capillary glass tube 1 form an F-P cavity 4 at the gap between the incident optical fiber 21 and the reflective optical fiber 22 . [0003] The optical fiber sensor is used for gas concentration or pressure testing, the optical fiber sensor is placed in the gas to be measured, the surface of the capillary glass tube 1 reacts with the gas to cause the axial extension of the capillary glass tube 1,...

AI Technical Summary

Problems solved by technology

[0004] However, in the specific measurement process, the temperature change will cause the expansion and contraction of the capillary glass tube, especially the capillary glass tube with a large thermal expansion coefficient, which will affect the measurement accuracy.

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