Optical fiber micrometric displacement sensor based on Mach-Zehnder interference and manufacturing method of optical micrometric displacement sensor

Abstract

The invention discloses an optical fiber micrometric displacement sensor based on Mach-Zehnder interference and a manufacturing method of the optical micrometric displacement sensor. The optical fiber micrometric displacement sensor is composed of an input single mode optical fiber, a first micrometric bending structure optical fiber, a conductive single mode optical fiber, a second micrometric bending structure optical fiber and an output single mode optical fiber; light is transmitted to the first micrometric bending structure optical fiber through the input single mode optical fiber and is divided into two parts in the first micrometric bending structure optical fiber; one part is transmitted as a fiber core basic mode in the first micrometric bending structure optical fiber; the other part is transmitted as a cladding mode in cladding of the first micrometric bending structure optical fiber; light transmitted as the fiber core basic mode is transmitted to a fiber core of the second micrometric bending structure optical fiber through the conductive single mode optical fiber; light transmitted as the cladding mode is transmitted to cladding in the second micrometric bending structure optical fiber through the conductive single mode optical fiber; part of the light transmitted as the cladding mode is coupled with the fiber core of the second micrometric bending structure optical fiber and interference light is formed by the light coupled with the fiber core and the light transmitted as the fiber core basic mode and the interference light is output through the output single mode optical fiber; the optical fiber micrometric displacement sensor based on Mach-Zehnder interference has the advantages of being high in sensitivity, simple in manufacture and low in cost.

Description

technical field [0001] The invention relates to an optical fiber sensing technology, in particular to an optical fiber micro-displacement sensor based on Mach-Zehnder interference and a manufacturing method thereof. Background technique [0002] When light is transmitted in the optical fiber, the characteristic parameters (such as amplitude, phase, polarization state, wavelength, etc.) that characterize the light wave will occur directly or indirectly due to external factors (such as temperature, refractive index, pressure, displacement, vibration, rotation, etc.) The optical fiber sensor is a kind of optical fiber sensing element that uses this basic principle to detect external physical quantities. Compared with ordinary photoelectric sensors, optical fiber sensors have the advantages of light weight, small size, anti-electromagnetic interference, electrical insulation, corrosion resistance, high sensitivity and long-distance control, and can effectively perform sensing op...

AI Technical Summary

Problems solved by technology

Among them, the sensing signal of the reflective intensity-modulated optical fiber micro-displacement sensor depends on the intensity of emitted light and received light, and is easily disturbed by the external environment; The sensing signal eliminates the interference of light intensity fluctuations, and has high reliability and stability. However, the production of these two optical fiber micro-displacement sensors requires sophisticated masks and expensive professional equipment. Not only the production cost is high, but also the production process Complicated; the gap between the two fiber end faces in the Fabry-Peort interferometric optical fiber micro-displacement sensor constitutes a microcavity, and the length of the microcavity changes with the change of the external displacement, resulting in a corresponding change in the interference output signal. The optical fiber micro-displacement sensor has high sensitivity, but because the two optical fiber end faces need to be precisely aligned, it requires extremely high environmental stability; the Michelson interferometric optical fiber micro-displacement sensor needs to be coated with a reflective film on the end face of the optical fiber. The manufacturing process is difficult; the existing Mach-Zehnder-based interferometric micro-displacement sensor first couples part of the core fundamental mode light to the cladding mode, and then couples part of the cladding mode light to the core fundamental mode , because there is a certain optical path difference between the light of the core fundamental mode and the light of the cladding mode, interference is formed, and the external micro-displacement is measured according to the formed interference spectrum, such as tapered optical fiber, dislocation fusion junction, core diameter Mach-Zehnder interferometric micro-displacement sensors with mismatched and other mode coupling structures, but the sensitivity of the above-mentioned Mach-Zehnder-based interferometric micro-displacement sensors is relatively low

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