The Sensing Characteristics Of Novel Micro-structer Interferomerter

Fiber-optic sensors have great advantages of wide range of measurements,strong immunity to electromagnetic interference,compact size and simple structure and easy integration.They can be used in all kinds of extreme conditions.With the intellectualization and integration of modern science and technology,the complexity and variability of application environment,fiber-optic sensors should possess the feathers of high precision,high sensitivity,miniature,multi-parameter sensing and networking.In this paper,a novel micro-structure based on fiber-optic Mach-Zehnder interferometer is designed.The main research works are as followsFirstly,we briefly introduce optical fiber sensing technology and fiber-optic sensors.Then we review the research status and progress of inline optical fiber interferometer sensors in recent years.We discuss the essential principles of traditional fiber-optic MZI,the fundamental theory of fiber-optic inline MZI,the sensing principles of refractive index and temperature.Then we propose that the response sensitivity can be improved by exciting higher order cladding modes.The light transmission and relative energy monitoring of the novel micro-structure are simulated.The fabrication process of the proposed micro-structure is demonstrated.The characteristics of transmission spectrum and corresponding spatial frequency spectrum are analyzed.We firstly carry out the sensitivity experiment of refractive index sensing on the micro-structure with the length of 400?m and 326?m in the solution of glycerol and water with the RI ranging from 1.3426-1.3844.Secondly,we investigate the sensitivity of temperature sensing on the micro-structure with the length of 400?m and 326?m in the temperature ranging from 15°C-600°C,and the high temperature ranging from 600°C-1000°C,respectively.Finally,the refractive index and temperature of 425?m length micro-structure are measured simultaneously.The minimum detection resolution obtained of the refractive index and temperature changes are 6.25×10^-5 RIU and 0.15oC,respectively.