Optical fiber chemical sensor of over-long optical absorption action distance and preparation method thereof

Abstract

The invention discloses an optical fiber chemical sensor of an over-long optical absorption action distance and a preparation method thereof. Long sensing optical fibers taken by the invention are compactly wound on a support to limit the size of a probe not to be overlarge; to prevent an optical fiber sensor head from being damaged and to effectively control optical fiber curving and straining, a decladding optical fiber is divided into a plurality of sections, and original optical fibers with cladding and coating exist between two sections so as to contact with a support and bear the curving and the straining. Thus, the sensor head is not easy to damage in the preparation and use process even if the sensing optical fiber is longer. An irregular groove is arranged on the contact part of the support and the optical fiber to enhance the disturbance to an optical fiber internal optical modal. The sectional structure of the sensing optical fiber, the curving and the straining in the winding process, and the like enable the optical energy of different models in the optical fiber to couple, and the energy of a low order model is constantly transferred to a high order model easily affected by medium to be tested so as to greatly increase the effective operating distance of optical absorption. The invention can be used for testing trace materials in liquid or gases with spectral absorption.

Description

technical field [0001] The invention relates to a device for optical fiber sensing and analyzing material components and a method for preparing the device, which is mainly used in the detection of trace substances in liquid or gas with spectral absorption. Background technique [0002] It is a common method to apply the principle of light absorption to analyze the composition of substances. Due to the different chemical structures of different molecules, they will have strong light absorption for different wavelengths of light. A specific molecule corresponds to a specific absorption wavelength. By detecting the degree of light absorption of a specific wavelength, the amount of the molecule can be judged. The method of light absorption to measure the content of a certain substance in a liquid or gas is not only related to its concentration, but also related to the distance of light passing through it. In general, the lower the concentration, the longer the optical path requ...

AI Technical Summary

Problems solved by technology

After all, there is no effective method suitable for liquids to greatly increase the distance of light absorption. If increasing the length of the optical fiber can still effectively sense the absorption of the medium to be measured, the ultra-long optical fiber sensing probe will greatly improve the detection sensitivity.

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