Hello All, I'm a new to learn MPB, and try to calculate effective index of PCFs. Altough I have read the following discussion, I still do not know how to calculate the effective index. Could anyone send me a sample "ctl" file to calculate the dispersion or effecitve index of PCF? Thanks.
Regards Guowei Steven G. Johnson Wed, 19 Apr 2006 12:51:36 -0700 On Wed, 19 Apr 2006, JT wrote: Do anyone know if it's feasible to calculate the dispersion, i.e. propagation diagram (omega-beta), of fibres (in particular: multi-step, graded-index, photonic crystal fibre, Omni guide fibre) with the MPB-package? If yes, where I can get an appropriate ctl-file? Did you have any luck with this? I also want to calculate the dispersion of PCFs. Anyone have any suggestions? Yes, we have done this many times. It's not particularly difficult in general...it's just a 2d calculation where the dielectric function is given by the fiber-cross section, and you set your k-point to be in the z direction (out of the plane). For index-guided fibers (e.g. solid-core PCFs, standard fibers, etcetera), it is a very small and easy calculation because you are interested in the lowest-lying bands, below the cladding light cone, so you only need to calculate a few bands. For hollow-core bandgap fibers the computation can be fairly large, because it is a supercell calculation and for an NxN supercell you need to compute O(N^2) bands before you get to the guided bands within the gap. For OmniGuide and Bragg fibers it is much more efficient to use a Bessel-function transfer-matrix method that exploits the cylindrical symmetry, since you really only have to solve a 1d problem in that case
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