PH value sensor based on tilted fiber Bragg grating girdle amplification welding technology

Abstract

The invention relates to a pH value sensor based on a tilted fiber Bragg grating girdle amplification welding technology. The pH value sensor is based on the principles that the refractive index of a pH sensitive film is modulated by liquid pH value, the reflected cladding mode is regulated by the external refractive index and the Bragg reflection mode is not modulated by the external refractive index, and prepared by the girdle amplification welding technology. The pH value sensor comprises a broadband light source, a coupler, a tilted fiber Bragg grating, the pH sensitive film, and a photodiode. The cladding mode returned from the tilted fiber Bragg grating is performed with the girdle amplification welding technology, then transmitted by optical fiber core, converted into analog electric signals, and introduced into a data processing module; the strength of the cladding mode is measured to obtain the refractive index of the pH sensitive film, so as to obtain the pH value. The pH value sensor adopts the theory that the external temperature change only influences the wavelength of the reflective spectrum to drift within a small range, so that the influence to the measurement from the temperature change can be effectively avoided. At the same time, due to the characteristic that the Bragg reflection mode of the tilted fiber Bragg grating is not influenced by the external refractive index, the influence of the broadband light source fluctuation to the pH measurement result can be avoided.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to a pH value sensor based on an inclined optical fiber grating beam waist amplification welding technology. Background technique [0002] The pH value is a standard to express the concentration of hydrogen ions in a solution, and it is also a commonly used measure of the acidity and alkalinity of a solution. Measuring and controlling the pH value has practical and important significance in the fields of biomedical diagnosis, clinical medicine, environmental science, engineering construction and industrial and agricultural production. For example, in seawater and natural water, the pH value has a very close relationship with the biological or chemical processes in the water. Through monitoring, we can quickly understand the relationship between the atmosphere, organisms and water; in biomedicine, the pH value of living blood Generally between 6.0 and 8.0, ...

AI Technical Summary

Problems solved by technology

At present, a large number of pH sensors based on optical fibers have emerged, but the disadvantage is that they cannot solve the cross-sensitivity effect caused by ambient temperature and light source fluctuations.

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