Discussion Forum

Dear All

Very sorry to bother you regarding my comsol model. The structure of my device is shown in the attachment. I've deposited an absorptive material (the thickness of the film is around 30 nm) on top of a SiNx waveguide along which the optical pulse is propagating in x direction. I assume that due to the evanescent coupling effect, the temperature inside the material can be changed. Therefore, I expect to solve the electromagnetic transient module and heat transfer module simultaneously, which can give the temperature distribution inside the materials. I found that comsol automatically created a multiphysics interface between electricmagnetic transient module and heat transfer module. Unfortunately, after solving this module, I have got very strange results. I used scattering boundary condition for the boundary of the waveguide where Gaussian pulse is incident and I defind the Gaussian pulse in terms of Ez in scattering boundary. Another side of the waveguide is also set as scattering boundary condition without incident field. Other boundaries are set as perfect electric conductor. For heat module, all the boundaries are set as room temperature. I attached my physica setting and the results to the attachment. I think perhaps there is something wrong with my boundary setting. Is it possible for you to give me some ideas? Thanks a million indeed for your help.



--
Wang Lei