A cavity length adjustable optical fiber f-p strain gauge based on mems technology and its forming method

Abstract

The invention discloses an optical fiber F-P strain gauge with adjustable cavity length based on MEMS technology, which belongs to the field of high-precision optical fiber sensing and measurement. The optical fiber F-P strain gauge mainly includes a F-P strain-sensitive MEMS chip and a collimated beam expanding optical fiber; wherein, the F-P strain-sensitive MEMS chip and the F-P strain-sensitive MEMS chip are made up of SOI silicon wafers and glass sheets. A circular hole is arranged in the axial direction of the SOI silicon wafer; the SOI silicon wafer is fixed on the glass wafer through silicon-glass anodic bonding; the collimated beam expanding optical fiber is fixed in the circular hole on the SOI silicon wafer by solder. The F-P pressure-sensitive MEMS chip is prepared based on MEMS micromachining technology, which can realize the miniaturization of the device, and flexibly adjust the initial cavity of the strain gauge F-P cavity according to practical application needs such as strain measurement sensitivity, range and wave grouping network. Long; the strain gauge has a high-precision F-P interference spectrum, can use wavelength signal demodulation to obtain high sensitivity and high measurement accuracy, and can realize multiple strain gauges on a single-core optical fiber through wavelength division multiplexing and time division multiplexing in series.

Description

technical field [0001] The invention relates to a cavity-length-adjustable optical fiber F-P strain gauge and a molding method based on MEMS technology, belonging to the field of high-precision optical fiber sensing and measurement. Background technique [0002] In engineering measurement technology, strain measurement is one of the most basic and important technologies. The resistance strain measurement method is a basic traditional means of obtaining strain test data. However, resistance strain gauges have poor fatigue resistance, serious zero drift, and are easily affected by environmental factors such as electromagnetic fields, temperature, humidity, and chemical corrosion, and cannot be used for long-term On-line measurement cannot meet the demand for accurate strain measurement in high temperature and electromagnetic environments. [0003] In recent years, as a new type of measurement method, optical fiber sensor has strong anti-interference (such as electromagnetic f...

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Problems solved by technology

However, these F-P optical interference cavities based on fiber end processing or fiber body micromachining cannot obtain a high-gloss reflective surface, and it is difficult to improve the optical reflectivity of the reflective surface through optical coatings. Therefore, it is difficult to improve the F-P optical interference cavity. The fineness of the interference spectrum makes it difficult to further improve the measurement resolution, and cannot meet the requirements of small-range, high-sensitivity strain measurement applications (such as high-speed wind tunnel aerodynamic measurement, multi-component dynamic force and moment measurement in the industrial field); and because the F-P optical interference cavity The interference fineness factor is low, and only intensity modulation and demodulation and phase modulation and demodulation signal demodulation methods can be used, which are easily affected by light source power fluctuations and fiber bending

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