Optical modeling of waveguide photonic nanostructures using the radiation spectrum method (RSM) with evanescent modes

In this work, we study the effects of the evanescent modes in the simulation and modeling of optical integrated circuits based on photonic bandgap structures. We show that the contribution of these modes in the energy transfer in structures like the MOEM structures, can not be neglected. The radiation spectrum method, recently developed by the authors for the guided wave devices, is thus extended to account for the evanescent mode propagation. Applying this technique on an air-gap in a suspended waveguide a model of this gap is developed in terms of its parameters. This model is then integrated in an all optical simulator to predict the performance of photonic structures. Such technique enables to design and to optimize the photonic integrated circuits taking the evanescent modes effects into account.