Eigenmode-expansion (EME) propagation through tapers, spot-size converters, directional couplers, MMIs, and Bragg gratings.
PIC Propagation simulates how light travels through z-varying photonic integrated circuit structures. The EME (eigenmode expansion) engine solves full-vectorial cross-section modes per section and cascades them through mode-overlap S-matrices, which makes device-length sweeps nearly free: the sections are solved once and re-cascaded per length point.
Device presets: linear and power-law tapers, inverse-taper spot-size converters with facet Gaussian overlap, directional couplers, 1×2 MMI splitters, and Bragg gratings. Waveguide crossings are reserved for the varFDTD engine, the second leg of this tool.
Cross-section modes come from the same solver behind the PIC Waveguide Mode Solver — use it to explore n_eff, dispersion, and bend loss of a single cross-section.