The computed waveguide mode can be used to find the overlap integral with another mode,
such as
**<E1(y) | f(y) | E2(y)>**
where **f(y)** is the function over which the integral is performed, where
**E1(y)** is the computed field distribution and **E2(y)** can be the same as **E1(y)** or the output from another mode calculation. In the latter case, the tag number of that calculation can be entered to perform the overlap.

The function **f(y)** can be entered the same was as
the refractive index, or trial function.

- An arbitrary profile can be uploaded as a two-column text file. The first column is the distance and the second column is the field value. Click here for an example of the file.
- The overlap function can be created using a set of built-in linear functions. Multiple functions can be entered, and most geometries of interest can be constructed this way. Click here for a complete description.