Temperature compensation sensing apparatus for sputtering palladium optical fibre grating

Abstract

The present invention discloses one temperature compensating hydrogen sensitive device with sputtered Pd film onto fiber grating. The laser beam from a laser is split with one 3 dB beam splitter into two beams; one beam is made to pass through the first three terminal circulator and enter to hydrogen-sensitive fiber grating on sealed box with sputtered Pd film; the other beam is made to pass through the second three terminal circulator and enter to hydrogen-sensitive fiber grating on sealed box with sputtered Pd film; and the reflected laser beams through individual three terminal circulators are fed to spectrograph and digital signal processing system. Thus, Bragg wavelength drift caused by ambient temperature and Bragg wavelength drift caused by the mixed change of temperature and hydrogen density are obtained separately, and thus the hydrogen density is measured. The present invention is insensitive to ambient temperature, reliable, antijamming and accurate.

Description

technical field [0001] The invention relates to a temperature compensation hydrogen sensitive device for sputtering a palladium film on an optical fiber grating. Background technique [0002] Palladium (Pd) is generally used as the catalytic substance in hydrogen sensitive technology, when H 2 When the gas encounters the Pd film, it is first adsorbed and then absorbed, and this catalytic reaction is reversible. The Pd film after hydrogen absorption usually has two solid solutions, which are α-phase and β-phase. The transformation from α-phase to β-phase is related to the concentration of hydrogen and the temperature of the surface environment. The lattice parameters of different phases are very different. Repeated adsorption and desorption will lead to the dislocation of the metal lattice, which will cause the Pd film to be distorted and even damaged after several cycles of hydrogen absorption and desorption. Therefore, it is necessary to comp...

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Problems solved by technology

At present, the most widely used method in the research of optical fiber hydrogen sensor is to coat one or more layers of Pd film on the end face of the optical fiber to form a microlens method; in addition, the use of Pd film and amorphous WO 3 As a hydrogen catalyst is also one of the early schemes, that is, in addition to coating the Pd film on the end face of the optical fiber, another layer of WO 3 Membrane, because this kind of sensor can produce strong absorption to the light wave of 800nm, so this method has very high sensitivity to the sensitivity of hydrogen gas, but the only shortcoming is that the response speed is relatively slow; Hydrogen sensitive sensors and hydrogen sensitive sensors with evanescent wave (Evanescent) structure have been reported, and the sensitivity of these methods to hydrogen sensitivity has been improved to varying degrees, but the test accuracy is generally difficult to reach 0.1%.

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