Trial Function
A trial function is the starting point for the mode solver. The choice of a trial function
determines which mode is found, and the speed of convergence, but it should not affect the
accuracy of the computed mode. Just like the refractive index profiles, the trial function
can be entered in one of three ways:
-
An arbitrary profile can be uploaded as a two-column text file.
The first column is the distance and the second column is the refractive index.
Click here for an example
-
The trial function can be created using a set of built-in polugon function. 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.
- The distribution profile from another job can be transferred to this job.
When a field, refractive index or function
is plotted
from the other program, there should be an option at the bottom of the screen for copying that
distribution as the trial function for another program.
Unlike the definitions of refractive index, the default background value is 0.0 (not 1.0).
Therefore, the trial function cannot be left blank. A trial function of zero everywhere
will crash the program. At the very least, a 'b 1.0' must be specified.