There are cases where you may want to simulate a region of air in between two components. A simple way of approaching this task is by creating a region with the same refractive index as air. The segment between the two waveguides (colored in gray) will serve as the “air” region. Right-click on the segment to define properties and under “Index Difference”, chose the value to be 1 minus the background index.
Properties for the segment:
Symbol Table Editor:
Notice that in the “air” region, the pathway monitor detects the efficiency to be zero, though the beam reconvenes in the waveguide, if the gap is short and the waveguide continues at the same angle, but with losses.