Dual-channel vibration measurement method and device based on optical fiber FP interference

Abstract

The invention particularly relates to a dual-channel vibration measurement method and device based on optical fiber FP interference. The method comprises the following steps: carrying out the light splitting of a first optical signal to obtain a second optical signal and a third optical signal, enabling the third optical signal to pass through an optical fiber circulator to obtain a fourth optical signal, enabling the fourth optical signal to pass through a first object to form a fifth optical signal, enabling the second optical signal to pass through a second object to form a sixth optical signal, carrying out regional Hilbert conversion on a first electric signal and a second electric signal which are converted from the fifth optical signal and the sixth optical signal, and measuring phase information of an object to be measured through an arc tangent function after quotient; and solving the phase information to obtain the vibration amplitude and the vibration frequency. The device comprises a laser, an optical fiber coupler, an optical fiber circulator, a first optical lens, a second optical lens, a first photoelectric detector, a second photoelectric detector, a data acquisition card and an upper computer. According to the method, the efficiency is improved, and the displacement reconstruction error is reduced; and the device is low in power consumption, simple in structure, easy and convenient to operate, low in price and low in cost.

Description

technical field [0001] The invention belongs to the field of vibration detection, in particular to a dual-channel vibration measurement method and device based on optical fiber FP interference. Background technique [0002] Light interference is due to the rearrangement of the light field intensities caused by the encounter of two light waves. The conditions for double beams or multiple beams to form interference are: the same optical frequency; the same vibration direction of the light vector (electric field intensity vector E); the phase difference is constant. Optical fiber vibration sensing technology refers to the conversion of external physical quantities such as displacement, speed, and temperature into signals such as light intensity, voltage, and current that change regularly. The vibration information is converted into another vibration-related and easy-to-measure physical quantity, and then through optical fiber transmission and photoelectric conversion, it is fu...

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Problems solved by technology

[0003] However, in the existing technology, based on the measurement application of optical fiber FP interference, there are problems such as spectrum aliasing, complex demodulation, non-independence and relatively complex structure in the acquisition and processing of two signals by a single PD.

Highly complex optical path problems based on two-beam interference

For example, disclosed by the Chinese Patent Office, the publication number is CN108458654A, and the name is a technical scheme based on a dual-channel quadrature phase-locked demodulation optical nonlinear error measurement method and device, and the device is relatively complicated

Publication number CN209690345U published by the Chinese Patent Office, titled as a technical solution for a speed measurement accuracy detection system based on a multi-channel laser interferometer, the complexity of the equipment is relatively high, and the complexity of the optical path is relatively high

Publication No. CN112414566 A published by the Chinese Patent Office, named as a technical solution for a terahertz wavelength dual-channel measurement device based on Michelson interference, which has the problem of low light splitting efficiency, high optical path complexity, and lack of simplification and integration The advantages

Disclosed by the Chinese Patent Office, the publication number is CN 108152323 A, and the title is a technical scheme of a device for accurately measuring the thermal expansion coefficient of a metal rod by two-way laser interference. It uses dual light sources, and the device is relatively complicated

Publication number CN 110057439 A disclosed by the Chinese Patent Office, titled as a technical scheme of a low-resonance eccentric optical fiber acoustic sensing device based on F-P interference, the device uses one path of light as a reference light, compared with the present invention, the The device cannot measure the information to be measured of the two-way object to be measured

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