Extracting TE mode phase information using FDTD::port on the waveguide
I am trying to reproduce the paper https://doi.org/10.1364/OE.27.018959, which is going to change the vertical gap between two vertical directional couplers to get phase change. Figures attached below are the schematic presentation of the phase shifter system, the FDTD::port location, and relative phase change versus the vertical gap, respectively.
Fig. 1 Schematic presentation of the system
Fig. 2 Port location
Fig. 3 Phase shift versus the vertical gap for λ = 1.55 μm.
Now I have built the model used in this paper in FDTD and tried to extract relative phase change at port2. However, the relative phase change extracted from my own model did not match with the paper. Especially when the gap = 160 nm, the phase value at port 1 even changed which was not supposed to be. Can someone help me check where the problem is?