codoped materials for optical waveguide

Dear all,

I have a multi-layered waveguide substrate which I want to simulate in Comsol. It's easy to create a particular geometry, but I don`t know how to create the materials with correct parameter, such as Er doped or Yt-Er codoped materials based on silica glass core or LiNbO3. Can you suggest me where to find material information about doped/codoped process (because of small micrometer structure (~2um), maybe the diffusion process is not appropiate). I find some particular properties about Er and Yt,...but in a codoped process the codoped behaviour is different (rate equation model). The concentration also has relevant influence on the active waveguide behaviour.

thanks