Modelling tools

This workshop is intended to give an insight into modelling techniques for photonics devices and systems. Three distinguished experts in modeling will give their view on simulation aspects of componentes as well as photonic systems. The first talk by S. Birner gives an overview of the nextnano project: the quickly progressing technology of low-dimensional semiconductor nanostructures requires reliable predictive theoretical methods for systematically improving and understanding the electronic and optical properties. nextnano is a semiconductor nanodevice simulation tool that has been developed for this purpose, and its core models will be presented in the talk. As example, a novel charge self-consistent electronic structure scheme for InAs/GaSb infrared detectors is presented and calculate optical transition energies as a function of layer width of broken-gap type-II superlattices will be calculated. The second talk by C. Hafner covers the theoretical background and various numerical techniques for handling both cylindrical and periodic waveguide structures — without losses and with material loss or radiation loss. Special attention is paid to complex eigenvalue problems and their numerical solution in presence of dispersive materials, such as noble metals that are relevant for plasmonic waveguide structures. Various types of optical waveguide structures are considered and discussed, in particular photonic crystal waveguides and plasmonic particle chain waveguides for short distance communications. The third talk by D. Gallagher will cover the modelling techniques for designing both passive and active photonic components, comparing the main approaches available — BPM, FDTD and EME (eigenmode expansion), and discussing each method´s applicability to common photonic components such as directional couplers, ring resonators, MMIs, AWGs, tapers. The talk then addresses the techniques to model larger photonic circuits composed of many individual component- - s, with a focus on the TDTW (time domain travelling wave) method. It will show how TDTW can be used to model details of active semiconductor photonic components, as well as the passive components introduced in the first section.