VarFDTD simulation for S bend in hybrid platform

- November 23, 2023 at 4:21 am
  
  Zhongdi Peng
  Subscriber
  
  Hi,
  I would like to ask how to simulate an appropriate parameter (x span, y span) in VarFDTD for S bend on a hybrid SiN-on-LN platform. The waveguide is fabricated in the SiN layer without etching LN layer below. And the index of SiN (1.9 @ 1550nm) is lower than that of LN thin film (2.1 and 2.3 for n_o and n_e @ 1550nm), thus we get a larger portion of mode energy located in LN (>60% electric field intensity). Since VarFDTD simplifies the 2D cross-section in FDTD into two 1D simulations, we need to define a X-Y plane where the waveguide is located inside with index contrast with surrounding material. If we choose the plane within SiN top region, we actually simulate the SiN waveguide with a single layer (SiNOI). If we define the plane in the LN bottom region, there is no index contrast to define the waveguide. I wanna know whether there are some methods to solve it.
- November 24, 2023 at 1:01 pm
  
  Niki Papachristou
  Ansys Employee
  
  Hi Zhongdi,
  Thank you for reaching out to us. Would your simulation work on an another plane in order to get the results you are looking for? If that the case have you considered rotating your device?
  Kind Regards,
  Niki