High-accuracy remote absolute displacement measurement system based on optical fiber composite interference

Abstract

The invention discloses a high-accuracy remote absolute displacement measurement system based on optical fiber composite interference, which belongs to the technical field of optical measurement and is composed of a board band light source, an optical fiber isolator, three 3dB couplers, four auto-collimation mirrors, two optical fiber gratings, four reflectors, two detectors, a circulator, a one-dimensional translation platform, piezoelectric ceramics, a feedback control circuit, a signal generator, a signal treatment circuit, an analog to digital (A / D) conversion card, a computer and result output. The high-accuracy remote absolute displacement measurement system uses an optical fiber interferometer to induce displacement and another optical fiber interferometer to demodulate displacement to achieve remote measurement. The optical fiber interferometer for demodulation works in a low coherence interference state and a high coherence interference state, and amplitude of displacement can be determined by low coherence signals to achieve absolute measurement. A value of the displacement can be measured by high coherence signals to feed back and control effects of environment interference on the demodulating optical fiber interferometer, and high-accuracy measurement can be obtained.

Description

technical field [0001] The invention relates to the technical field of optical measurement, in particular to a high-precision remote absolute displacement measurement system based on optical fiber composite interference. Background technique [0002] The existing literature close to this technology has the following two: [0003] [1] D.P.Hand, T.A.Carolan, J.S.Barton, and J.D.C.Jones. "Profile measurement of optically rough surfaces by fiber-optic interferometry", Opt.Lett., Vol.18, No.16, 1993, P.1361-1363 .(Optics Letters, Vol. 18, No. 16, P.1361-1363) [0004] The technical principle of literature [1] is as follows: figure 1 shown. [0005] The light emitted by the semiconductor laser passes through the Faraday isolator and the fiber 3dB-coupler, and then reaches the measuring head. The measuring head is a Fizeau interferometer. A part of the light is reflected by the end face of the fiber as the reference light, and the other part of the light is focused by the self-f...

AI Technical Summary

Problems solved by technology

[0015] 1. Only local displacement can be measured, remote measurement is not possible

[0016] 2. The measurement range is limited by the wavelength λ of the incident light wave, the measurement range is very small, only λ / 2, and the displacement with a span greater than λ / 2 cannot be measured

[0017] 3. Absolute measurement cannot be performed

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