An All-Fiber Interferometry Method Using Polarization Encoding to Suppress Backscattering
A backscattering light and backscattering technology, which is applied in the field of all-fiber interference, can solve the problems of system signal-to-noise ratio reduction and limited measurement sensitivity, so as to improve the signal-to-noise ratio and realize the effect of backscattering suppression
Active Publication Date: 2021-07-27
EAST CHINA NORMAL UNIV
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[0003] The present invention provides an all-fiber interference method using polarization encoding to suppress backscattering, aiming to solve the problems caused by the loss in the optical path and the accumulated backscattering in the sensing fiber in the existing long-distance optical fiber sensing measurement technology. The system signal-to-noise ratio is reduced, which limits the measurement sensitivity
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[0050] In order to illustrate the technical solutions of the present invention, specific examples are used below to illustrate.
[0051] The all-fiber interference method using polarization encoding to suppress backscattering according to the present invention comprises the following steps:
[0052] Step 1: A signal transmitting module is composed of a coherent light source to generate two beams of light waves (x-polarized light and y-polarized light) with orthogonal polarization;
[0053] Step 2: In the phase modulation module, use the x-polarized light and y-polarized light generated by the above-mentioned signal transmitting module to sense the phase caused by the external physical field. In this process, the optical paths of x-polarized light, y-polarized light, parasitic backscattered light of x-polarized light and parasitic backscattered light of y-polarized light are as follows: figure 1 shown. Wherein, x-polarized light and y-polarized light are equal optical path pr...
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The present invention proposes an all-fiber interference method that uses polarization encoding to suppress backscattering. Using polarization encoding technology, the two beams of coherent light waves are vertically polarized and propagate with equal optical paths, while the backscattered light in the interference optical path is unequal Optical path propagation. Combined with low-coherence interference technology, effective light interference can be achieved while backscattered light cannot interfere, and an all-fiber interference method with backscatter suppression characteristics is realized. The device of the invention includes a signal transmitting module, a phase modulation module and an interferometric measurement module. Among them, the signal transmission module generates two beams of light waves with orthogonal polarization; the phase modulation module realizes equal optical path transmission of polarized orthogonal light waves, and the unequal optical path transmission of parasitic backscattered light; the interferometric module realizes equal optical path transmission. program interference. Compared with traditional all-fiber interference, the method and device of the present invention reduce the influence of backscattering and realize high-precision interferometric measurement of long-distance transmission through polarization coding and low-coherence interference technology.
Description
technical field [0001] The invention relates to the technical field of optics and precision measurement, in particular to a brand-new all-fiber interference method using polarization coding to suppress backscattering. Background technique [0002] Distributed optical fiber sensing is widely used in perimeter early warning, oil pipeline detection and other fields due to its advantages of long life, high sensitivity, high voltage resistance, good resistance to electromagnetic interference, and simple system. However, when realizing ultra-long-distance optical fiber sensing, due to the limitation of optical path loss, the effective light decays exponentially with the increase of sensing distance. In addition, due to the non-ideality of optical fibers and devices in the optical path, part of the light interacts with free-oscillating molecules, atoms and other particles in the optical fiber, resulting in backscattered (reflected) light. The spurious light formed by the backscatt...
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IPC IPC(8): G01D5/353
CPCG01D5/35358
Inventor 吴媛郭进先
Owner EAST CHINA NORMAL UNIV