Detection Method Optimization of Optical Fiber Evanescent-wave Hydrogen Gas Sensor

摘要

As the optical power variation is relatively small before and after the Pt/WO_3 film was exposed to hydrogen gas, traditional detective method to measure directly the variation of optical power in the fiber core is susceptible to interference. Therefore a new detection method, which is able to improve the relative variation for nearly 9 times by detecting the variation of optical power in the evanescent field, was proposed through mathematical analysis and simulations. The fundamental structure and working principle of step-index single mode optical fiber sensor were introduced.