Fiber laser single-wave self-mixing interference displacement measuring system

Abstract

The invention discloses a fiber laser single-wave self-mixing interference displacement measuring system, and belongs to the technical field of optical measuring. The system comprises a pumping source, a laser device, five optical fiber gratings, three optical fiber isolators, two detectors, an Er-doped fiber, piezoelectric ceramic, a 3dB coupler, a circulator, a collimating mirror, a wavelength division multiplexer, a variable optical attenuator, a signal processing circuit, a feedback control circuit, an A / D (analog to digital) conversion card, a computer and result output. A pair of optical fiber gratings with the same reflection wavelength is used as a laser resonator mirror to generate single-wavelength laser; the single-wavelength laser is projected to a measured object surface, reflected or scattered back to a laser cavity through a measured object to generate self-mixing interference with light in the cavity, so that displacement measuring with nano-scale resolution is realized. The system can measure a low-reflectivity object due to an amplifying effect of a gain medium in the laser cavity; output wavelength of the laser device is stabilized through feedback control, so that the measuring precision is greatly improved; the fiber laser device is not only a sensor, but also an interferometer, is simple in structure and easy to carry.

Description

technical field [0001] The invention relates to the field of optical measurement, in particular to a fiber laser single-wave self-mixing interference displacement measurement system. 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, Volume 18, Issue 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. 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-focusing lens and projected On the m...

AI Technical Summary

Problems solved by technology

[0015] 1. Difficult to measure objects with low reflectivity

[0016] 2. The measurement results are affected by the spectral drift of the light source, and the measurement accuracy is difficult to improve

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