Rsoft is a powerful tool for optical and photonic simulations and design. Rsoft and Synopsys packages come with a number of different tools and simulators, such as BeamPROP, FullWAVE and more. There are also other programs typically found with Rsoft such a OptoDesigner, LaserMOD and OptSim. Here we focus on the very basics of using the Rsoft CAD environment. I am using a student version, which is free for all students in the United States.
New File & Environment
When starting a new file, the following window is opened. We can select the simulation tools needed, the refractive index of the environment (“background index”) and other parameters. Under dimensions, “3D” is selected.
The 3D environment is displayed:
On the side bar, select “Edit Symbols.” Here we can introduce a new symbol and assign it a value using “New Symbol,” filling out the name and expression and selecting “Accept Symbol.”
Next we will draw a rectangle, which will be our waveguide. Select the rectangular segment below:
Now, select the bounds of the rectangle. See example below:
Editing Component Parameters
Right click on the component to edit parameters. Here, we will now change the refractive index and the length of the component. The Index Difference tab is the difference in refractive index compared to the background index, which was defined when we created the file. We’ll set it to 0.1 and since our background index was 1.0, that means the refractive index of the waveguide is 1.1. Alternatively, the value delta that was in the box may be edited from the Symbol menu. We also want to use our symbol “Length” to define the length of our waveguide. We also want this waveguide to be tapered, so the ending vertex will be set to width*4. Note that width may also be edited in the symbol list.
Here, we have a tapered waveguide: