I am trying to simulate the single mode fiber coupling and would like to see how the beam profile looks like when the incoming beam to the fiber is converging or diverging by changing the shape of the lens. I created a simple system with a lens, and inserted the fiber as a non-sequantial component. Since the core diameter is too small and length of the fiber is too large compared with the lens, I cannot see what's going on inside the fiber from the layout plot. I tried to use the standard spot diagram to see the beam profile, but it only gives me a single point. The receiver efficiency also drops from 99% to around 1% after I inserted the fiber. Does anyone know whether my method is incorrect or Zemax is not capable of performing such systems? Thanks a lot!

Haofeng Sun