Diffused Waveguides

Simulation of Ti-diffused, Ge-diffused and ion-exchange with FIMMWAVE software

FIMMWAVE can efficiently model waveguides generated by diffusion processes. It can for instance calculate the modes of Ti:LiNbO3 waveguides in which Titanium is diffused in a Lithium Niobate substrate, of Ge:Si waveguides in which Germanium is diffused in a Silicon substrate, or ion-exchange glass waveguides. Such waveguides are widely used in electro-optic devices.

You can conveniently define diffused refractive index profiles in FIMMWAVE by several means, for example:

• by specifying the size and position of a diffusion source plus a diffusion length,
• by defining a Gaussian and erf profile,
• by importing an arbitrary profile from your own file.

The FDM Solver is ideal for finding modes of diffused waveguides thanks to its fine mesh which can readily render the diffused profiles with a resolution of a few nanometers.