  Based on the basic theory of the microfiber loop resonator, we exploit the
application of microfiber loop resonators in biochemical 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
datas as the parameters in the expression of intensity transmission
coefficient, and the detection limit reaches to a varation of ambient
refractive index of 10-5 refractive index unit(RIU). This has superiority over
the exsiting evanescent field-based subwavelength-diameter optical fiber
refractive index sensor.
