Microfiber Resonator Temperature Sensin

In recent years,due to outstanding merits of optic fiber sensors(e.g.easy integration and strong resistance to electromagnetic interference)they have been widely applied in various fields such as biomedicine,gas monitoring,chemical and food ingredient detection et al.Microfiber resonator sensing units are gradually emerging in optical sensing technology based on their advantages of high-quality factor,strong stability,simple structure and easy to fabricate.Under the above-mentioned background,we treated microfiber knot resonator as main study subject and deeply researched on the microfiber fabrication theory and difference analysis of two resonator fabrication methods.Then,we constructed the sensing system which based on microfiber junction resonator and performed a series of sensing experiments responding to the change of external environment such as temperature and refractive index.Finally,some improved methods for enhancing device stability and temperature sensitivity were presented.The main research content is listed as follows:The transmission theory of microfibers and micro-ring resonators was mainly analyzed,and their output characteristics were studied by use of simulation software.Key parameters such as microfiber size and micro ring size were systematically analyzed through theoretical derivation and simulation which lays the theoretical foundation for the subsequent fabrication and research of microfiber knot resonator.Experimental analysis was conducted on the core parameters of the fused biconical taper system,and combined with theoretical research for determining the optimal parameters to manufacture eligible microfibers.Then,the fabrication method of microfiber knot resonator was chosen by comparative analysis on different fabrication methods.The main factors affecting the properties of resonators were studied by parameter tuning,and the minimum size of resonator was further explored.Under the condition that the diameter of the microfiber is set about 1.9 μm,the diameter of the resonant cavity could reach 79 μm.In this case,the temperature sensitivity and refractive index sensitivity of microfiber knot resonator were tested and obtained-19.98 pm/℃ and 250.64 nm/RIU,respectively.After enhancing the device stability by changing the structure of coupling zone,the minimum diameter of the improved resonant cavity is 91 μm and the minimum diameter of the resonant cavity is reduced to 91 μm and the corresponding temperature sensitivity is-20.59 pm/℃.Experimental research on the refractive index response of the improved device shows that when the resonant cavity diameter is 117 μm,the refractive index sensitivity is 255.99 nm/RIU with the linearity of 0.9985.