1. Import normalized index data file
By default, user-defined profiles (see Section 6.A in the RSoft CAD manual) normalize both the coordinate and refractive index information to achieve the final profile. The general index profile equation is written as
n(x',y') = n0 + Δnf(x',y'),
where x'=2x/w, y'=2y/h, and n0 is the background index and Δn is the index difference.
There are different ways to convert our measured data file to be used as f(x',y'). The simplest and most efficient way is to set Δn to 1 and change the data range to (-1,1) for x and y as shown in Figure 4.
A normalized user profile can be used for any components in the project with different widths and heights as well as use the same profile for different background indices. It offers the flexibility to use the same profile distribution in different environments. Figure 5 shows an example of how we can create different size waveguides at different locations with the same user profile. Furthermore, the background index can be set as a different number from the original file.