All-fiber-optic displacement measuring method and device thereof

Abstract

The invention designs an all-fiber-optic displacement measuring method and a device thereof. The device comprises a dual-band orhtogonal linear polarization light source, a polarization-maintaining fiber optic coupler, a fiber optic polarizer, a photoelectric detector, a micro focus lens, a reflecting mirror, an oscilloscope and the like. Reflected light of a measured object and reflected light of the reflecting mirror are fixed to form a beat-frequency signal and a beat-frequency signal generated with reference light, and the two paths of signals are subtracted to obtain displacement information. The invention adopts a dual-band laser light source and a heterodyne interference to output, is not influenced by the light-intensity fluctuation, outputs alternating-current signals, and can adopt an alternating-current amplifier to amplify the signals, thus avoiding the problems of the direct-current offset and the like; and simultaneously, the invention adopts an all-fiber-optic structure, is difficult to be influenced by the external conditions such as environment and the like, has high measuring accuracy, and is applicable to the severe environments such as a factory shop and the like.

Description

[0001] Field [0002] The invention relates to the field of laser interferometry, in particular to an all-fiber displacement measurement method and device, which can be used in harsh environments such as factory workshops. Background technique [0003] Obtaining various dynamic response characteristics of materials under high strain rate loads is a key research issue when constructing constitutive relations, equations of state, and conducting research on laser shock strengthening, laser shock forming, and spalling. Considering that the embedded sensor will interfere with the properties of the measured object and the shock waves generated, optical methods are generally used for precise non-contact real-time measurement. [0004] The Chinese patent "An all-fiber displacement interferometer" with the application number CN200510022172.X uses an optical probe to illuminate the surface of the sample to be tested and returns signal light. The change process of the Chinese patent "co...

AI Technical Summary

Problems solved by technology

However, when the measured object does not move, the output of the all-fiber laser displacement interference system is a DC signal, which is very easy to cause the loss of DC drift; at the same time, the single-frequency laser is used, the output is easily affected by the fluctuation of the light source, and the light intensity of the coherent light Matching is relatively difficult and the system stability is not strong

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