## Overlap Integral

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 two-dimensional profile can be uploaded as ASCII numeric values. This profile must conform to the following format:

 xp xd[1] xd[2] xd[3] xd[4] ... yd[1] N(x=1,y=1) N(x=2,y=1) N(x=3,y=1) N(x=4,y=1) ... yd[2] N(x=1,y=2) N(x=2,y=2) N(x=3,y=2) N(x=4,y=2) ... .. ... ... ... ... ... yd[N] N(x=1,y=N) N(x=2,y=N) N(x=3,y=N) N(x=4,y=N) ...
where xp is the number of points along the x direction, and xd[1], xd[2] etc.. are the grid point distances along the x-axis. yd[1], yd[2[ etc.. are the grid point distances along the y-direction. Click here for an example file.

• The trial function can be created using a set of built-in polygon functions. Each polygon is a two dimenssional shape. The field value inside the polygon is specified by the user, and the field outside the polygon is zero. Multiple polygons can be entered, and most geometries of interest can be constructed this way. Click here for a complete description.