How to obtain the propagation loss in phase-shifted bragg grating waveguide

- March 25, 2024 at 6:29 am
  
  Kim Kang Seok
  Subscriber
  
  Good day,
  I'm trying to obtain an accurate propagation loss in the phase-shifted Bragg grating structure by using two analysis methods: EME solver and 3D FDTD, respectively. Although I know the solution using FDE solver to multiply loss by the total length, it is preferred for infinite waveguides rather than for the grating structures. There are additional losses which are the sum of radiation loss, coupling loss, scattering loss, and so on.
  It is important for me to ultimately calculate the Q factor by using the obtained losses. I would be grateful if someone could introduce the right method to calculate these losses.
  Thank you.
- March 25, 2024 at 6:56 pm
  
  Guilin Sun
  Ansys Employee
  
  You can use FDTD simulation to get Q and resonate frequency. Pleae refer to Quality factor calculations for a resonant cavity
  other examples https://optics.ansys.com/hc/en-us/sections/360006919094-Resonators
  You can use both FDTD and EME to get the totla loss, with loss=1-R-T.
  However, if the loss is small, the result might be very senstive to mesh accuracy and other factors.
  Please check which method is better for you.