Analysis of multilayer semiconductor rib waveguides with high refractive index substrates

Analysis of leaky modes in deep-ridge waveguides using the compact 2D FDTD method

“…In the simulation, 1 mm-thick UPMLs and a uniform space cell with size of 0.0125 mm were used. Table 1 shows the imaginary part of the complex mode indices of five TE modes at the wavelength of 1.064 mm calculated by this modal, the SIM method [6], the edge element method [5], the IDVFE-BPM method [3], and the FEID-BPM method [2]. It can be seen that our results are in good agreement with those obtained by the other methods except the TE 20 mode.…”

“…The calculated complex mode indices for the TE fundamental mode is 1.44620 2 j4.720 Â 10 24 , which is in good agreement with the theoretical value (1.44622 2 j4.721 Â 10 24 ). Then a 3D ARROW waveguide with the same structure as in [6] was analysed. In the simulation, 1 mm-thick UPMLs and a uniform space cell with size of 0.0125 mm were used.…”

“…It is rather challenging to accurately calculate such complex effective mode indices with such small imaginary parts through numerical simulations. Several methods have been used to solve this problem, such as the finitedifference method [1], the imaginary beam propagation method based on the finite-element scheme [2, 3], the eigen-equation solving method based on the finite-element scheme [4,5], and the spectral index scheme [6]. These methods search the complex effective indices in the complex plane through iteration processes and are generally initial-guess sensitive.…”