Simulation of Optical Microfiber Loop Resonators for Ambient Refractive Index Sensing

Abstract: Based on theoretical modeling and optimization, we exploit the application ofoptical microfiber loop resonators in ambient refractive index sensing. We set up a reliabletheoretical model and optimize the structural parameters of microfiber loop resonatorsincluding the radius of the microrfiber, the radius of the loop and the length of the couplingregion for higher sensitivity, wider dynamic measurement range, and lower detection limit.To show the convincible and realizable sensing ability we perform the simulation ofsensing an extreme small variation of ambient refractive index by employing a set ofexperimental data as the parameters in the expression of intensity transmission coefficient,and the detection limit reaches to a variation of ambient refractive index of 10^-5 refractiveindex unit (RIU). This has superiority over the existing evanescent field-basedsubwavelength-diameter optical fiber refractive index sensor.