Research On Sensing Characteristics Of Fused Biconical Taper Optical Microfiber Couplers On Hybrid Structure

With the development of optic,fiber optic sensing technology is also improving,optical fiber also plays a key role in the field of communication.Optical fiber sensing technology has high security,because it uses optical signal as the carrier of information and uses optical fiber for signal transmission.The transmission process is light signal,so it strong to electromagnetic interference.It can work in inflammable and explosive environmental extremes and can realize long-distance detecting.The traditional fiber coupler is a device with the function of splitting light,and fiber coupler belong to Optical Passive components.Of course,it is also of great significance in the research of detection and sensing.The main content of this paper is as follows:Firstly,this paper introduces the interferometric fiber optic sensors,and developmental for optical fiber couplers,application and classified.This paper briefly introduces the recent years,optical fiber couplers must be tested and research from various physical parameters,such as refractive index,temperatures,gas density magnetic field and current.Then,the basic principle of optical microfiber couplers and coupling theory are analyzed theoretically.And three preparation methods of fiber couplers are introduced.In this paper,fiber couplers were fabricated from optical single-mode fiber?SMF?using the flame brushing method.The temperature,Axial micro strain and concentration of salting liquid sensing characteristics of fiber couplers are experimentally studied.The results show that,the bare fiber couplers(without any sensitivity enhancing material adhered has a poor temperature sensing ability.The sensing characteristics of axial micro strain and concentration of salting liquid,the experimental results show that the structural axial micro strain sensitivity can reach 0.0129nm/??,the concentration of salting liquid sensitivity can reach 127.261.nm/g.ml^-1At last,a novel fused biconical taper optical microfiber couplers on hybrid structure is designed and fabricated,and application in axial micro strain and salt solution sensing.Both the optical microfiber coupler and the Mach-Zehnder interferometer in the hybrid structure.The optical microfiber coupler is mainly responsible for precisely sensing small scale strain variations,and the Mach-Zehnder interferometer focuses on measuring strain in large operation range.Then,the sensing characteristics of axial micro strain and concentration of salting liquid.Comparison of experimental results of hybrid structure fiber coupler and 2×2 fiber coupler,and the experimental results show that the concentration of salting liquid sensitivity can reach78.2098.nm/g.ml^-1.