Research On Fiber-Optic Hydrogen Sensor And The Processing Technique On Sensing Fiber Facet

With the development of fiber-optic communication, fiber-optic sensors have been used in more different fields. With the advantages of low price, simple and stable structures and good sensing properties, fiber-optic interference sensors have been given more attention than ever.Firstly, a brief introduction of various types of fiber-optic sensors was given, especially about the widely used, wavelength modulated fiber-optic grating sensors. To solve the problems of grating sensors, we presented a thin-core fiber modal interferometer (TCFMI) and discussed its sensing principle and properties.Secondly, we presented a catalytic hydrogen sensor based on TCFMI, of which the Pt/WO3thin sensing film would perform an exothermic reaction with hydrogen, thus changing the temperature around TCFMI, as a result, the transmission spectrum of TCFMI would change with the presence of hydrogen. Because of the reversibility of the reaction, the sensor can recover after put back in air.Finally, a new method to produce micro structures on fiber facets is produced. We applied laser interference lithography technology into the mass production of fiber facet devices. This method is both cheap and easy to perform, as well as can be used in the mass production of fiber facet sensors, which would be of great importance in the promotion of fiber facet devices. We have achieved producing fiber facet sensors using this method, which are based on multi-beam interference to sense the change of reflective index around. We have simulated the reflective spectrum change when reflective index around changes and have carried sensing experiments on the sensors produced.