Dear Jacob,
The “Free Space Optics” directory in OptiSystem 16.1 has one component called “LOS Channel”. It is used to be called “Diffuse Channel” in older versions. The LOS channel is the proper name. This component has a lens model build in it, where users can enter “Optical concentrator factor” to setup the gain of the lens and set up the lens index of refractive. You could check the component’s datasheet for more information. You can access it by clicking the help button in the component properties window.
Regard,
Ahmad