Ultra-short base line differential plate type optical fiber displacement sensor and optical fiber strain gauge

Abstract

The invention provides an ultra-short base line differential plate type optical fiber displacement sensor and an optical fiber strain gauge. The ultra-short base line differential plate type optical fiber displacement sensor comprises an outer frame, wherein an outer ring of a displacement conversion device is tightly pressed on the outer frame by a pressing ring with external threads, a threaded pillar of a central press washer penetrates through a central hole in the displacement conversion device, and a first Faraday rotating mirror and a second Faraday rotating mirror are solidified on the central press washer; and an optical fiber coupler and a phase modulator are fixed on the surface of the inner wall of the outer frame, the outer frame and a fixed base are fixed, a first measurement optical fiber and a second measurement optical fiber are respectively wound into multilayered optical fiber loops with hollow plate type layered structures, the first measurement optical fiber and the second measurement optical fiber are respectively solidified on the upper surface and the lower surface of the displacement conversion device, the coupler is connected with the fist Faraday rotating mirror, the phase modulator and a detector, the fist measurement optical fiber is connected with the first Faraday rotating mirror, the phase modulator is connected with the second measurement optical fiber, and the second measurement optical fiber is connected with the second Faraday rotating mirror. The ultra-short base line differential plate type optical fiber displacement sensor and the optical fiber strain gauge are mainly used for observing earth crust strain and solid tide, and acquiring earthquake precursor information.

Description

technical field [0001] The invention relates to an optical fiber sensing and measuring device, in particular to an optical fiber displacement sensor for geophysical research, observation of crustal strain and solid tide, and acquisition of earthquake precursor information, and a strain gauge mainly composed of the optical fiber displacement sensor. Background technique [0002] The strain gauge is an instrument that precisely measures the relative change of the distance between two points in the crustal rock mass. It has important applications in the fields of observing crustal strain and solid tides, as well as studying the process of earthquake breeding and obtaining earthquake precursors. [0003] Since the American seismologist H. Benioff developed the first valuable quartz extensometer in 1935, the United States, Britain, the former Soviet Union, Japan, Belgium, Germany and other countries have successively developed high-sensitivity extensometers. instrument. The sens...

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Problems solved by technology

[0008] Displacement sensors currently invented in strain gauges mainly use eddy current displacement sensors, differential transformer displacement sensors, or capacitive displacement sensors, among which the best displacement resolution of the first two is about 1nm; , can reach 0.01nm, but there are shortcomings such as parasitic capacitance and distributed capacitance that have a great impact on sensitivity and measurement accuracy, output is nonlinear, connection circuit is complicated, and it is affected by humidity and electromagnetic interference, etc., it is not suitable for long-term stability and reliability of strain gauges. work needs

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