• get_modes.m: Computes the TE0/TE1 modes in the 2D slab waveguide using the effective-index method.
• input_WG.m: Computes the resultant field at the output port of the SiO₂/Al₂O₃ slab waveguide with no perturbations.
• single_simulation.m: This is the main simulation executable. It Computes the complex E-field profiles along the transverse and propagation directions in the periodic perturbation-based TE0/TE1 mode converter using the Beam Propagation Method based on the Crank-Nicolson Scheme. The overlap integral of the propagating field with the TE0/TE1 are computed at every z-step to monitor the modal powers. The simulation parameters like the grating periodicity, grating tooth width, and waveguide length can be tuned.

When the simulation ends, the overall |E|² profile is plotted and the modal power of the TE0/TE1 modes are plotted as a function of propagation direction.