Polarization fading restraining device and method for white light interferometry sensor array

Abstract

The invention provides a polarization fading restraining device and method for a white light interferometry sensor array. The polarization fading restraining device is composed of a wide-spectrum light source, an optoisolator, an optical fiber coupler, an optical path delay line, an optical fiber sensor array, an optical detector and a signal collecting, processing and displaying unit and further comprises a polarization state continuous rotation mechanism. When optical path matching occurs between the optical path delay line and a certain optical fiber sensor, and the polarization state changes continuously and rapidly within the range from 0 degree to 360 degrees, the amplitude of white light interferometry signal intensity of the sensor goes through the whole changing process from maximum to minimum; the sum of the intensity of any two interference peak values with the polarization state difference of 180 degrees is taken as an output signal of the sensor, polarization fading caused by elements such as the optical fiber sensor, the delay line and transmission optical fibers can be restrained, and the polarization fading restraining device has the advantages that a polarization element is not introduced, the control process is easy and convenient to carry out, and the incidence polarization state does not need to be considered. The polarization fading restraining device and method can be used in the fields of real-time monitoring and measuring of multi-point strain or temperature, and monitoring of a large-size intelligent structure and the like.

Description

technical field [0001] The invention relates to a polarization fading suppression device of a white light interference sensing array. The invention also relates to a method for suppressing polarization fading of a white light interference sensor array. In particular, it relates to a device and a method for suppressing the influence of polarization fading caused by polarization state degradation on interference signals in white light interferometry technology due to the rotation and extrusion of optical fibers constituting an optical fiber sensing array. Background technique [0002] Optical fiber white light interference sensing technology is a sensing measurement method based on the principle of white light interference. In addition to its strong anti-interference ability and the ability to measure absolute physical quantities, it also has the advantages of not being affected by electromagnetic fields. However, in the application process, it was found that the white light ...

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Problems solved by technology

This method is effective against polarization fading, but its device is more complicated

[0004] In recent years, there have been some other public reports of anti-polarization fading methods: the patent document "Michelson optical fiber sensor with controllable polarization fading and phase fading" published by Zhao Ruifeng et al. on March 18, 2009. Two polarization modulators are connected in series in the photosensitive path to achieve polarization fading suppression. At the same time, the dual light source scheme is adopted in the optical path. The system introduces many additional components and is relatively complicated, which increases the cost input.

On February 13, 2009, Wang Chunhua and others disclosed the patent document "Anti-polarization fading and phase noise all-fiber Mach-Zehnder interferometer", in which the implementation scheme is to realize the spatial path decomposition of optical components by bridging and cascading optical fiber ring chains , the interference detection result is the statistical average of the interference results of countless pairs of tiny light pairs with the same phase difference, the same light intensity, and random distribution of polarization states. Brings unwanted spurious interference peaks to the demodulation of cascaded fiber optic sensing arrays

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