A fully polarization-maintaining reflection type hydrogen concentration detection device

Abstract

The invention discloses an all polarization-maintaining reflection type hydrogen concentration detection device. The device comprises a light source, a fiber polarization beam splitter, a hydrogen sensing head, a spectrum analyzer and a signal processing unit. The main body of the hydrogen sensing head is a section of polarization-maintaining photonic crystal optical fiber, a palladium membrane isplated on the side face of the hydrogen sensing head, and one end of the hydrogen sensing head is connected with a thin coreless optical fiber plated with a reflective film so as to form a reflectivephotonic crystal optical fiber hydrogen sensing head. Polarization-maintaining tail fibers of the light source are fused with incident polarization-maintaining tail fibers of the polarization beam splitter by 0 degree so as to form a polarization-maintaining fiber light path; the polarization-maintaining tail fibers output by the polarization beam splitter are fused with the polarization-maintaining photonic crystal optical fibers of the hydrogen sensing head by an angle theta, signal light reflected by an end face of the polarization-maintaining photonic crystal optical fibers reaches the spectrum analyzer via the polarization beam splitter and the polarization-maintaining tail fibers, and the processing results are processed by the signal processing unit. The light path of the device istotally the polarization-maintaining fibers, the hydrogen sensing head is also of an all polarization-maintaining reflection structure, and the device is simple and reliable in structure, stable in performance and convenient to mount and is capable of realizing hydrogen concentration detection in a narrow space.

Description

technical field [0001] The invention belongs to the technical field of gas concentration detection equipment, and in particular relates to a fully polarization-maintaining reflection type hydrogen concentration detection device. Background technique [0002] Due to its own characteristics, such as: low density, low boiling point, high reducibility, high diffusion coefficient and high combustion heat, hydrogen plays an irreplaceable role in the field of energy and reducing agent. However, it is precisely because of these characteristics of hydrogen that it is extremely prone to leakage during storage and transportation. When the concentration of hydrogen leaked into the air reaches more than 4%, the air becomes flammable. An explosion occurred, threatening the safety of human life and property. Therefore, how to monitor the concentration of hydrogen in the environment in real time has become an important research topic for the safe and efficient use of hydrogen. [0003] Si...

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Problems solved by technology

[0004] At present, typical fiber optic hydrogen sensors include microlens fiber optic hydrogen sensors, Bragg grating fiber optic hydrogen sensors, evanescent field fiber optic hydrogen sensors and interference fiber optic hydrogen sensors. single-mode or multi-mode optical fiber, which greatly limits the sensitivity and service life of the sensing head; the sensing unit of the Bragg grating-type optical fiber hydrogen sensor is a grating, but the cost of the grating itself is relatively high, and it is also It is easily affected by the ambient temperature, which seriously limits its use effect; the sensing unit of the evanescent field optical fiber hydrogen sensor forms an evanescent field near the fiber core, which has high requirements on the manufacturing process and is not easy to Commercialization; the interferometric optical fiber hydrogen sensor has high measurement accuracy and good repeatability, but it is easily affected by the ambient temperature and its structure is relatively complicated

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