In this video we will learn about the various applications of the FEEM solver in DEVICE
and some of its advantages over its finite-difference counterpart, FDE, in MODE Solutions.
The FEEM solver, just like FDE, can be used to design passive waveguides, such as strip
or rib waveguides or optical fibers.
However, the key application area of the FEEM solver is the simulation of active waveguides
such as phase shifters or modulators.
This includes electro-optic modulators where variations in the charge distribution are
responsible for refractive index perturbations.
Thermo-optic phase modulators where the index perturbation comes from variation in the waveguide
Or other types of optical modulators, for example those where the refractive index is
affected by an applied electric field through the Franz-Keldysh effect.
The FEEM solver in DEVICE has important advantages over the FDE solver in MODE Solutions.
It is fully integrated in the DEVICE design environment, which includes the CHARGE, HEAT
and DGTD solvers.
This makes it easier to perform multiphysics simulations because all of these solvers are
in the same environment and all of them use a finite element mesh.
For example, you can use the CHARGE solver to calculate the charge variation of a depletion-type
pn phase shifter and model its optical properties in FEEM, or you can use HEAT and FEEM together
to model a thermo-optic modulator.
You can even perform a coupled electro-thermal simulation using CHARGE and HEAT for an injection
type electro-optic modulator, where both charge variation and Joule heating play a role in
the optical performance, and get the optical modeling done with FEEM, all inside DEVICE.
The other advantages of FEEM come from its finite-element mesh, which is more efficient
for modeling complex geometries with curved surfaces.
Also, the higher order basis functions in FEEM offer faster convergence compared to
FDE as the simulation mesh gets refined.