I am simulating a silicon strip waveguide using the FDE solver in MODE Solutions and I would like to calculate the mode confinement factor (the fraction of power of the mode that is in the core region). How can I get this result?

# How can I get the confinement factor in the waveguide core?

**smshim**#1

Optical confinement factor using Lumerical Mode Solutions

Confinement factor variation using nested sweep script in FDE solver

Confinement Factor Optimization in MODE Solutions

**nlui**#2

Since you are using the FDE solver, a simple way to get the fraction of power in a given region of the waveguide cross section is to use the “Power and Intensity Integration” feature in the modal analysis tab of the Eigensolver analysis window after you have solved for the waveguide mode. There is more information about this feature here:

https://kb.lumerical.com/en/index.html?layout_analysis_eigensolver_power_intensity_integration.html

I also need to calculate the confinement factor, but my cross-section has a complex shape. Is it possible to calculate it? Thanks

**nlui**#4

It is possible to get this result by creating a spatial filter which has values of 1 over the core and 0 outside of the core. Once you have the spatial filter you can multiply the E intensity by the filter then integrate the result over the filter to get the power in only the core region. This process is described in more detail on this related post:

Please take a look and let me know if it works for you!