Simulation of optical microfiber loop resonators for ambient refractive index sensing

Based on theoretical modeling and optimization, we exploit the application of optical microfiber loop resonators in ambient refractive index sensing. We set up a reliable theoretical model and optimize the structural parameters of microfiber loop resonators including the radius of the microrfiber, the radius of the loop and the length of the coupling region for higher sensitivity, wider dynamic measurement range, and lower detection limit. To show the convincible and realizable sensing ability we perform the simulation of sensing an extreme small variation of ambient refractive index by employing a set of experimental 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) refractive index unit (RIU). This has superiority over the existing evanescent field-based subwavelength-diameter optical fiber refractive index sensor.