Learning Forum

[Md. Atiqur Rahman]

1. I'm a new user of lumerical fdtd and trying to simulate a directional coupler in SOI platform. One waveguide tapered down from 840 nm to 835 nm and another waveguide is 400 nm wide. Gap between them is 200 nm. During simulation at 1550 nm wavelength Neff for TE1 is 2.21929 but when I set the source wavelength range from 1530-1565 nm the Neff for TE1 at center wavelength ~1550 nm changes to 2.26563. Please can anyone tell me why this happening?

2. Can I do wavelength sweep simply by setting min wavelength and max wavelength in source settings? or I have to use optimization and sweep window to do wavelength sweep?