Optical waveguide modes

This java applet (program) is loaded and you run it on your own computer.
You give the cross section of the guide and it computes the propagation modes.
The scalar wave equation is solved (basically an eigen value problem) through mode decomposition in orthogonal basis functions i.e. a mode is defined and searched for through very effective techniques, as a sum of these basis functions weighted with coefficients. The eigen values are the effective indices while eigen vectors are the weighting coefficients of each mode.
You launch the decomposition with the 'sines menu', while you choose how many even and odd sines functions (symmetrical : 'even' and assymmetrical : 'odd') you want in both directions. Alternative expansion will be available with Gauss Hermite polynomials.
After the decomposition, you visualize a mode with 'Mode menu' .

Cross section is drawn through four nodes polygons to fit arbitrary shapes (quite new!). Drawing is possible with mouse and/or dialogs. An adjustable rectangular domain defines the whole section area. As a demo, a shape is provided, but can be deleted and replaced by your own section. Just click on the sines menu with the number of even and odd functions you want in X and Y. This gives the effective indices of the propagating modes . Then click on the mode menu to display a mode you choose (be a little patient please!).

If you see this statement, then your browser does not support Java applets.

P>Tricks : An r typed after the shape number, transforms the current shape to a rectangle (simpler computations). Inverse transform : s.A tnn typed after the shape number, turns the shape of nn degrees. mdx,dy moves the shape of dx, dy microns. After the wavelength in the same textfield (globals display), you can enter lxxxx or uxxx to give a lower (upper) limit to the effective index, msines,a,b,c,d to sim ulate a menu with text sines,a,b,c,d ...

The source for the main program for the drawing part and for the Object 'shape' for the sines expansion, and matrix solver

Other example of sections( which can be modified) may be found : elliptical fiber, rounded waveguide, 5 x 5 um wave guide

and now your personal guide (an HTML page you save, modify at home and launch directly from your computer)
This software is developped by Yves Moreau and Jérôme Porque. Some parts were inspired by the Numerical Photonics Library of F Ladouceur (Australian National University).

See also papers :
Y. Moreau, J. Porque, P. Coudray, P. Etienne, K. Kribich, "New simulation tools for complex multilevel optical circuits", International Conference SPIE, "Optical design and analysis software", Denver, USA, July 1999
Y. Moreau, J.Porque, P. Coudray, P.Etienne, "Etude modale de guides à section quelconque", Proc. JNOG 98, pp.67-69, Marly le Roi (France), Oct. 1998.

Any comments, suggestions... feel free to contact Yves Moreau