A Highly Sensitive Optical Fiber Curvature Sensing Structure with Temperature Insensitivity

Abstract

The invention proposes a high-sensitivity optical fiber curvature sensing structure with temperature insensitivity. The three-core optical fiber is used as the central sensitive element, and the three cores of the three-core optical fiber are arranged in an equilateral triangle. The broad-spectrum light enters the multimode fiber 9 through the single-mode fiber 3, excites multiple transmission modes, and the transmission mode field becomes larger, and then enters the three-core fiber 10, and the three core modes independently transmit a distance L and then re-enter the multimode fiber 9 , at this time, the light of the three modes interferes, the light signal is modulated, and then continues to propagate forward in the single-mode optical fiber 3 in a single-mode form, and is finally recorded by the spectrum analyzer 2 . The amount of curvature change can be estimated by detecting the shift amount of the interference spectrum. The experimental results show that the optical fiber sensing structure can measure the bending curvature and obtain good linear characteristics, and the measurement sensitivity can reach ‑28.29nm / m‑1 when the curvature range is 2.79 m‑1~3.24 m‑1.

Description

technical field [0001] The invention relates to a high-sensitivity optical fiber curvature sensing structure with temperature insensitivity, belonging to the technical field of optical fiber sensors. Background technique [0002] Curvature is a very important parameter in many fields such as industry, manufacturing and construction, such as robotic arms, building structure health monitoring, bridge construction, machining of mechanical parts, micro-electromechanical systems, etc. However, since it is difficult to be directly measured in practice, the curvature information is indirectly deduced through information such as the strain of the structure, so the direct measurement of the curvature becomes a difficult problem. Traditionally, there are many methods to obtain the bending deformation of the structure, but most of them are restricted by certain conditions, such as the inability to recover after deformation, and not suitable for embedded measurement. Therefore, the opt...

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Problems solved by technology

[0005] The purpose of the present invention is to overcome the shortcomings of existing optical fiber curvature sensors that are easily affected by temperature, and propose an intermodal interference curvature sensing structure that is simple in structure, easy to prepare, and capable of high-sensitivity measurement

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