Optical waveguide modes
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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 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 squared effective indices while eigen vectors are the weighting
coefficients of each mode.
- You launch the decomposition with the Mode menu or with the 'sines menu', where you choose
how many even and odd sines functions (symmetrical : 'even' and assymmetrical
: 'odd') you want in both directions (symmetry saves computation time) for decomposition.
- After the decomposition, you visualize a mode with 'Mode menu' .
- Also you choose scalar mode (much simpler, valid for low to moderate index contrast) or vectorial
where you choose which component you look for.
Cross section is drawn through four nodes polygons to fit arbitrary
shapes (this is 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.
Extra: The text zone in the upper right corner, lets you enter commands such as:
- -f fileX : Shapes are read in the file fileX.
- -s shapeArgs : A shape is added according to descriptive (see chained shpes menu for format).
- -o fileX : Text output is redirected to file fileX.
- -l valeur : assigns a lower limit for effective index to be displayed.
- -u valeur : assigns an upper limit for effective index to be displayed.
- -m menuString : launches a menu menuString such as sines12,12,12,12
Also, an r typed after the shape letter (right side), transforms the current shape to its (outer) rectangle (simpler computations); type r : rect to shape (necessary before turning [rotating] ...).
: s.A tnn typed after the shape number, turns the shape of nn degrees. mdx,dy moves the shape of dx, dy microns.
Other example of guide 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 . Some parts were inspired by the Numerical Photonics Library of
F Ladouceur (Australian
National University).
See also papers :
Y. Moreau, G. Pille, J. Galy, "Guides optiques à section transverse quelconque : un calcul scalaire et vectoriel en ligne", Journées Nationales Microélectronique et optoélectronique, p.161, La Grande Motte, 8-11 juin 2004.
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