Optimization of silicon nitride Y-branch optical waveguide for evanescent field biosensor

Evanescent field had been widely used in bio and chemical sensors. However in most cases, evanescent field is not maximized and thus the performance of the sensor is not optimized. It is the aim of the paper to optimize the design of 1:2 Y-branch splitter optical waveguide through simulation by using FD-BPM. Y-branch splitter without taper are simulated to optimize the power loss. Width of waveguide and effective angle are manipulated in the power loss optimization. The result shows that evanescent field is maximized at optimized thickness and width. The result suggests that Y-branch splitter with width of 25μm, effective angle of 6.24° is the best design for evanescent field sensor application with both high sensitivity and signal to noise ratio.