In-plane transmission simulations were performed using Tidy3D (Flexcompute, Inc.) with a point source polarized along Z (perpendicular to the plane of the crystal). The X and Y boundary conditions were set to the built-in 'absorber' option, and the Z boundary condition was periodic. A perfect electrical conductor (PEC) layer was placed above and below the crystal to approximate the parallel plate waveguide. The high-accuracy simulations compared with our experimental measurements were performed using 128 mesh cells per unit cell along X and Y, and 3 mesh cells along Z (one mesh cell for each PEC layer and one for the crystal, effectively a 2D simulation). The 4096 high-speed simulations for optimizing corner geometry were performed using 32 mesh cells per unit cell along X and Y, and one mesh cell each for the crystal and PEC layers along Z. The bent waveguide structure possesses mirror symmetry across the plane perpendicular to the propagation axis. For the corner optimization process, we therefore simulated only the first half of the bent waveguide to decrease simulation time. All transmission spectra were acquired by measuring the electric field amplitude at a time-domain monitor and taking the Fourier transform and normalizing by subtracting the simulated spectrum with no crystal present.