I would like to use the tilted mode expansion monitor to understand the mode coupling into higher order mode of a bend-straight directional coupler. However, the simulation always seems to diverge and the mode expansion calculation will always fail. Note that without the mode expansion monitor, the script runs fine and I would be able to calculated the power coupling ratio.
Could someone help me figure out what is the solution to this? Script attached.ring_gap_v4.lsf (7.4 KB)