Method for determining liquid medium refractive index by using optical fiber sensing technology

Abstract

The invention belongs to a method used in liquid medium refractive index determination employing an optical fiber sensing technology. The method comprises steps that: a composite optical waveguide is constructed; a composite optical waveguide grating is produced by compression, and a refractive index measuring system is constructed; and the refractive index of a liquid requiring determination is determined. According to the invention, the composite optical waveguide is composed of the liquid medium requiring determination, a common monomode fiber, and a sleeve pipe; two rack plates with a same teeth interval are used for compressing the composite optical waveguide, such that a composite optical waveguide grating is produced; two ends of the composite optical waveguide grating are respectively connected to a broad-spectrum light source generator and a spectrum analyzer, such that the liquid refractive index measuring system is obtained. The broad-spectrum light source generator and the spectrum analyzer are started, and the refractive index of the liquid requiring determination can be obtained through an obtained transmission spectrum and a central wavelength thereof. Therefore, the method provided by the invention is advantaged in simple measuring system structure and simple measuring method. Refractive index can be realized with the common monomode fiber. The measuring system can be tuned, and can be repeatedly used. The method is advantaged in convenient operation, low manufacturing cost, and low application cost.

Description

technical field [0001] The invention belongs to the measurement technology of the refractive index of liquid medium, in particular to a method for measuring the refractive index of liquid medium using optical fiber sensing technology, which can be widely used in biochemical application fields such as environmental monitoring, medical diagnosis, and petrochemical industry Indirect measurement of the content (concentration) of the chemical constituents of the liquid medium. Background technique [0002] Refractive index is a basic physical parameter that reflects the internal information of matter. Physical quantities related to the refractive index, such as the content (concentration) of substances, can be indirectly measured by measuring the refractive index, so the measurement of the refractive index is widely used in environmental monitoring, petrochemical and other biochemical fields. Therefore, the research on the measurement method of the refractive index has important...

AI Technical Summary

Problems solved by technology

The photonic crystal fiber and side-hole single-mode fiber are produced by the pressure method to produce a fiber grating with a period of hundreds of microns. Although the stress change is temporary (that is, elastic deformation), the grating effect is immediate after the pressure is removed. disappear without permanent changes to the physical structure of the optical fiber, and can be reused; however, these two types of specially designed optical fibers are difficult to manufacture, expensive, and require optical fiber adapters when connecting with light sources and spectrometers. Disadvantages such as complicated operation process and limited application range

In addition, because the material of the cladding of ordinary single-mode optical fibers is uniform, there is no small hole for the liquid to be tested to be directly injected into the small hole, so this method is not suitable for ordinary single-mode optical fibers

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