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Application Gallery

This page contains detailed instructions on how to create the project file in FEEM.  Alternatively the project file provided in the top-level page can be used to go through the steps in the Results and Discussion page.

Material Database

Open a blank simulation file in FEEM.  Under the Material section of the Design tab of the tabbed toolbar, click on the Optical button icon_device_optical_material_zoom94 to open the optical material database.  The material database contains more than 40 different optical models for common materials.  The user can also add new material models to the database using the "New Material" button.  Additionally, material models can be imported from other FEEM, FDTD, or MODE project files using the "Import material" button.

 

Materials

 

"Si (Silicon) - Palik" and "SiO2 (Glass) - Palik" materials must be added from the database to the materials object (only optical properties) in Objects Tree. To do this you have two options:

 

1. Under the Materials section of the Design tab, click on New Material button icon_design_newmaterial_zoom94. Then right click on recently added New Material under the Material Group in Objects Tree and click on Add optical properties. This will automatically open Optical Material Database. Scroll it down to find Si (Silicon) - Palik from Material List and click on Select. This will add the material along with its optical properties to the objects tree.

 

2. Click on the Optical button icon_device_optical_material_zoom94 to open the optical material database. Select Si (Silicon) - Palik and then click on Create button as is shown below:

 

soi_wg_gs_material_add_zoom60

 

This will add the optical properties of the silicon material into the Objects Tree. After adding the properties, you can rename the new material by double clicking on its name or right click and then select rename. The same procedure should be followed to add SiO2 (Glass) - Palik to the simulation.

 

Geometry

The Structures section of the Design tab icon_structures_tab_zoom64  can be used to introduce various types of structures into the simulation space.  The available options vary from simple rectangles and spheres to complex waveguides and planar solids.  In this example, we will use two rectangles to define the silicon waveguide and the surrounding oxide cladding.

 

wg

From the Structures section of the Design tab, select a RECTANGLE to be added to the Objects Tree. Select the rectangle in the Objects Tree and click on the "Edit Properties" button icon_edit to edit the properties of the rectangle according to the following table.

tab

property

value


name

wg

Geometry

x (um) / x span (um)

0 / 0.5


y (um) / y span (um)

0 / 3


z (um) / z span (um)

0.11 / 0.22

Material

material

Si (Silicon) - Palik

 

oxide

From the Structures section of the Design tab, select another RECTANGLE to be added to the Objects Tree. Select the rectangle in the Objects Tree and click on the "Edit Properties" button icon_edit to edit the properties of the rectangle according to the following table. Note the mesh order is set to 5 (a higher number than the default 2) so that the "oxide" structure will not fill the volume it overlaps with the "wg" structure.  The alpha value is set to 0.1 to make the object transparent so the "wg" structure inside it can be seen in the viewport.

tab

property

value


name

oxide

Geometry

x (um) / x span (um)

0 / 3


y (um) / y span (um)

0 / 3


z (um) / z span (um)

0.11 / 3

Material

material

SiO2 (Glass) - Palik


mesh order

5

Graphical rendering

alpha

0.1

 

 

Simulation Region

 

Click on icon_simulation_region in the Objects Tree and click the icon_edit button (on the left of the Objects Tree) to edit its properties according to the following table:

tab

property

value

General

dimension

2D Y-Normal


x min boundary

closed


x max boundary

closed


z min boundary

closed


z max boundary

closed

Material

background material

None

Geometry

x (um) / x span (um)

0 / 2.5


y (um)

0


z (um) / z span (um)

0.11 / 2

 

 

FEEM Solver Region

In the Solvers section of the Design tab select the "FEEM" button to place an FEEM solver in the simulation environment.  Note that once the solver is selected, all the simulation objects (i.e. constraints, boundary conditions, etc.) belonging to the solver become available under a new tab named FEEM.  Select the FEEM object from the Objects Tree and click on the "Edit Properties" button icon_edit to edit the properties according to the following table.

tab

property

value

General

simulation region

simulation region

Mesh

edges per wavelength

2


refine based on material properties

enabled


polynomial order

3

Modal Analysis

sweep type

single > wavelength


wavelength (um)

1.55


number of trial modes

20


use max index

enabled

 

Check Partitioned Volume

Click on the "Partition simulation region" button to view the partitioned volume (Fig. below).  The partitioned volume mode shows the entire simulation volume and identifies the different domains and surfaces.  Each domain and surface has a unique identifier and they are listed under the "simulation region" in the Objects Tree.  As you select different domains and surfaces in the Objects Tree the corresponding volume or surface gets highlighted in the partitioned volume.  In the figure below "domain 1" is highlighted in the partitioned volume.

 

Fig: Partitioned volume with the waveguide (domain 1) highlighted.

Fig: Partitioned volume with the waveguide (domain 1) highlighted.

 

Mesh Constraint

In Solver section under the FEEM tab, press on the CONSTRAINT button icon_CHARGE_constraint to add a Mesh Constraint to the objects tree.  Select it from the Objects Tree (under FEEM) and click on the "Edit Properties" button icon_edit to edit the properties according to the following table.

section

property

value


name

wg_mesh

General

Maximum edge length (um)

0.01

Geometry

geometry type

surface


surface type

solid


solid

WG

 

 

Boundary Conditions

The last step in setting up the simulation is to add the boundary conditions at the simulation boundaries.  

 

PEC

In most FEEM simulation, the simulation boundaries are defined as perfect electrical conductors using the PEC boundary condition.  Click on the PEC button in the Boundary Conditions section under the FEEM tab in the tabbed toolstrip and add a PEC object in the objects tree.  Click on the "Edit Properties" button icon_edit to edit the properties according to the following table.

tab

property

value


name

PEC

Geometry

surface type

simulation region


x min

enabled


x max

enabled


y min

disabled


y max

disabled


z min

enabled


z max

enabled

 

Error Check

The project file is now set up.  Next check if there is any error in the simulation setup by clicking on the "Check" button.  This will open up the "Error Checking and Diagnostics" window that shows any error in the simulation setup as well information about the different simulation objects (Fig. below).  There should be no warnings.

 

Fig: Error check and diagnostics.

Fig: Error check and diagnostics.

 

The project file is now set up.  Save the file using the "File" menu and run it by following the instructions provided in the Results and Discussion page.

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