Generation of two Fano resonances using 4×4 multimode interference structures on silicon waveguides

We propose a novel microring resonator coupled 4×4 generalized Mach Zehnder interferometer (GMZI) structure to produce Fano resonance line shapes. The structure can produce two independent Fano resonance line shapes. Two phase shifters are introduced in two arms of the 4×4 GMZI to control the variation of the Fano line shapes. The other aim of this study is to use silicon waveguides, that are compatible with the existing CMOS (Complementary Metal-Oxide-Semiconductor) fabrication technology, for designing the proposed devices. The transfer matrix method (TMM) and beam propagation method (BPM) are used for analytical analysis and first order design of the device. Finally, we discuss potential applications of the new device for sensing, all-optical switching applications and generation of electromagnetically induced transparency (EIT) effect.