We propose a new structure for generating a Fano shape. This structure can be applied to design an optical sensor with a high sensitivity based on intensity mechanism using a 2×4 multimode interference (MMI) coupler. The sensor structure can provide a very sensitivity (higher than 10 times) compared with the traditional structure based on Mach Zehnder interferometer (MZI) and microring resonators (MRR). For CMOS compatibility, we use silicon on insluator (SOI) waveguide for the whole sensor designs. The sensing structure can work at operating wavelength of 1550nm, that is suitable for fiber-optic communication and real-time measurement applications.
