Understanding the Light Expert Parameters

The following section describes the Light Expert parameters to set in simulation.

LPF Max Path Parameter

The LPF max path corresponds to the maximum number of rays the Light Path Finder file (*.lpf or *.lp3) can contain.

According to the simulation, the rays are integrated differently in the file:

In Direct Simulation, rays are selected randomly.
In Inverse Simulation, rays are basically selected according to the order in which the pixels of the map are computed (1^st pixel with all wavelength sample, 2^nd pixel with all wavelength samples, etc.).
Example: For a 1000*1000 pixel map with 10 wavelength, 10e6 rays are propagated per pass in the system. When setting LPF max path to 10e6, only 10% of the map is covered.

We recommend you to set a LPF max path parameter equivalent to the number of rays propagated in the system. Otherwise, when LPF max path is much more smaller than the number of rays, information will not be integrated in the analysis.

Warning: The *.lpf file size increases with the number of rays interaction. The more interactions in the system, the bigger the *.lpf file size.

To avoid such situation, you can create small sensor (not a lot of pixel) to cover the area on which you want to perform a Light Expert analysis with a *.lpf file.