Learning Forum

[Hamed Nikbakht]

dear all,
I need help with a 3D fdtd solution for the simulation of the ring resonator,
as you see in the pic I designed a ring with a waveguide I send a broadband light from one side of the waveguide and see the transmission on the other side
by increasing the simulation time FWHM of deeps becomes thinner but by getting thin, two thin deeps appear, and this is so strange to me, could you please help me with this issue?
I did this simulation with var-fdtd and I see the same results

simulation details: Si ring on SiO2 substrate,  diameter: 8um, waveguide cross-section: 400nm x400 nm, gap: 100nm, source: 1550 with 50nm span, mesh accuracy: 3,  

[Guilin Sun]

You may need to use override mesh for the coupling region to well resolve the small gap, and use smaller autoshutoff min and long simulation time to improve the result.