以有限差分頻域法分析光波導與多模干涉器件

Abstract

In this research, the ‾nite-di®erence frequency- domain (FDFD) method is adopted to analyze optical waveguides with di®erent cross-sections and related multi-mode interference (MMI) devices. The perfectly matched layer (PML) is employed as the absorbing boundary of the computing window in the FDFD solver. Several optical waveguides including channel waveguides, rib waveguides, optical ‾bers, photonic wires, and two kinds of low loss fabricated waveguides are analyzed. The concept and phenomena of the MMI are introduced, and we utilize the modal propagation analysis and the FDFD mode solver to analyze and design the MMI. The MMI phenomena for di®erent input positions are also investigated. Finally, we try to design simple MMI power splitter devices using the structure of a photonic wire and a low loss etchless waveguide, respectively, and discuss the imaging length and the coupling e±ciency versus the width of the multi-mode waveguide.