Discussion Forum

Hello Vishal,

Can you clarify?

Is it that you know how the refractive index of silicon nitride changes with temperature and you are looking for advice on how to account for this in a COMSOL model? Or are you looking for someone to tell you how the refractive index of silicon nitride changes with temperature? Or are you hoping that someone has already determined by way of a COMSOL model how the refractive index of silicon nitride changes with temperature (that seems like a long shot)? or something else?

Jeff

Hi Jeff,

My question is as follow,

I want to use metal heater on top of waveguide. I will give DC bias to metal heater, it will generate heat. This heat will transfer to underlying layers of waveguide. I have silicon nitride waveguide on top of the silicon oxide cladding.

Now heat transfer will change temperature in silicon nitride and silicon oxide layer. I have equations to model refractive index with temperature. My concern is how to use temperature data for each layer of waveguide.

In short, based on DC bias, get heat profile. Based on Heat profile, get temeprature data for each layer. How can I achieve this everything in one simulation.

Thanks Vishal

Hello Vishal,

In that case, it's just a matter of employing interpolation functions to specify the refractive index of each material in your RF simulation step, after having performed a preliminary Joule heating simulation step. See the Reference Manual for COMSOL Multiphysics, or this Discussion Forum, for more information on interpolation functions.

Jeff