Multimode Interference Structures for Photonic Signal Processing

This book proposes, designs, and optimises multimode interference (MMI) devices using the silicon on insulator (SOI) platform for photonic signal processing applications. Based on the self- imaging phenomenon within the multimode interference regions, a variety of signal processing functions can be achieved in the optical domain with MMI structures as well as performing the basic coupling functions. MMI devices can carry out more complex optical filtering, optical logic and signal processing transforms. The devices are optimised using the three-dimensional beam propagation method (3D-BPM), the three-dimensional eigenmode expansion method (3D-EME), the full- vectorial finite-difference method (FV-FDM), the two-dimensional finite-difference time-domain (2D- FDTD) method and the finite element method (FEM).