Abstract
A novel silicon-on-insulator microring biosensor based on Young's twos lit interference has been demonstrated. The transducer signal from electric field intensity distribution on the interference screen is given by using the transfer matrix method (TMM) and two-slit interference principle. The result shows that the structure we propose is advantageous for sensing as the interference pattern is very sensitive to the ambient refractive index around the microring. A small perturbation in refractive index around the microring Δnc will result in a notable shift of destructive interference points (DIPs) on the interference screen. By detecting the shift of the DIPs, the ambient refractive index change can be obtained.