Bragg grating biochemical sensor and method at interface between fiber core and cladding

Abstract

The invention discloses a Bragg grating biochemical sensor at the interface between the fiber core and the cladding and a method thereof. The Bragg grating biochemical sensor at the interface between the fiber core and the cladding includes an optical fiber core and an optical fiber cladding wrapping the optical fiber core. In that: the front section of the fiber core is provided with a long-period fiber grating, and the middle section of the optical fiber is located at the interface between the fiber core and the fiber cladding to set a Bragg grating at the interface between the fiber core and the cladding; the fiber core and the cladding The Bragg grating at the interface is composed of several linear grooves or several point-shaped grooves; the linear grooves or point-shaped grooves are periodically distributed along the axial direction of the optical fiber; the fiber core and The outer surface of the optical fiber cladding corresponding to the Bragg grating at the cladding interface is adsorbed with a silane layer; the invention can be widely used in the fields of biology, chemical industry, medicine, 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 of an optical fiber core and a cladding layer and a manufacturing method thereof. Background technique [0002] The basic principle of the fiber 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 grating includes two basic types: fiber Bragg grating and long-period fiber grating. Among them, the long-period fiber grating is the core mode of the fiber to the same direction cladding mode, and the evanescent field of the cladding mode can be affected by the external medium to be measured, resulting in the change of its resonance wavelength or intensity for measurement. However, long-period fiber gratings are not only very sensitive to...

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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