Bragg grating biochemical sensor at interface of fiber core and cladding

Abstract

The invention discloses a Bragg grating biochemical sensor at interface of a fiber core and a cladding and a method. The Bragg grating biochemical sensor at the interface of the fiber core and the cladding comprises the fiber core and the fiber cladding wrapping the fiber core, and is characterized in that the front segment of the fiber core is provided with a long-period fiber grating, the middle segment of the fiber is provided with a Bragg grating at the interface of the fiber core and the cladding; the Bragg grating at the interface of the fiber core and the cladding is composed of a plurality of linear grooves or point-like grooves; the linear grooves or the point-like grooves are periodically distributed along the axial direction of the fiber; and the external surface of the fiber cladding corresponding to the Bragg grating at the interface of the fiber core and the cladding is provided with a silane layer through adsorption. The technical scheme is widely applicable to fields such as biology, chemical engineering, medical science, life science and the like.

Description

technical field [0001] The invention relates to an optical fiber sensor, in particular to a Bragg grating biochemical sensor at the interface between an optical fiber core and a cladding layer and a manufacturing method thereof. Background technique [0002] The basic principle of the fiber Bragg grating biochemical information sensor is to indirectly estimate the value of the measured parameter or evaluate the state information of the biochemical process parameter by measuring the small change in the refractive index of the external medium. [0003] Fiber Bragg gratings include two basic types: fiber Bragg gratings and long-period fiber gratings. Among them, the long-period fiber grating is from the core mode to the cladding mode in the same direction, and the evanescent field of the cladding mode can be measured by the change of its resonance wavelength or intensity due to the influence of the external medium to be measured. However, long-period fiber gratings are not onl...

AI Technical Summary

Problems solved by technology

But its disadvantages are: the fiber Bragg grating is made by the traditional ultraviolet exposure phase mask method, and special fiber materials with photon-sensitive cladding are required to make the fiber Bragg grating to ensure that the fiber Bragg grating is written in the core At the same time as the Bragg grating, the Bragg grating inside the cladding is formed near the interface between the cladding and the fiber core, but the intensity of the Bragg grating inside the cladding formed by this method is very small, so the reflection intensity of the cladding mode resonance is very low. Moreover, the Bragg wavelengths of the cladding mode and the fiber core mode are coupled twice by the long-period fiber grating, so the resonance intensity of the reflected cladding mode and the fiber core mode detected at the reflection end is also very weak

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