Thank you Mr Ahmad for your kind response
I could do the simulation as intended using Ideal Circulator
However, I can’t seem to make my simulation work with Circulator or Bidirectional Circulator (I’m trying everything). The closest result I get is when I use Optical Delay on reflective path and Optical Null on the circulator output (bottom one). The transmitted wave is fine but the reflected one is the same as the output from the light source.