In this paper, a design for a 1 × 4 optical power splitter based on the multimode interference (MMI) coupler in a silicon (Si)-gallium nitride (GaN) slot waveguide structure is presented-to our knowledge, for the first time. Si and GaN were found as suitable materials for the slot waveguide structure. Numerical optimizations were carried out on the device parameters using the full vectorial-bea...

A novel spectral method with variable transformation, the adaptive Hermite-Gauss decomposition method (A-HGDM), has been developed and applied to the analysis of three-dimensional (3D) dielectric structures. The proposed method includes an optimization strategy to automatically find the quasi-optimum numerical parameters of the variable transformation with low computational effort. The techniqu...

Directional couplers are critical components in photonic integrated circuits used in optical communication systems. The conventional directional couplers with laterally arranged waveguides can not achieve very short coupling lengths due to extreme sensitivity to fabrication variations and limitations to produce uniformly very narrow gap layers.1) Vertical directional couplers, however, can obta...

Magnonics is an emerging field with potential applications in classical and quantum information processing. Freely propagating magnons in two-dimensional media are subject to dispersion, which limits their effective range and utility as information carriers. We show the design of a confining magnonic waveguide created by two surface current carrying wires placed above a spin-sheet, which can be...

Recent high power tests of x-band accelerating structures at SLAC have shown that their performance is limited by breakdowns in couplers. The behavior of these breakdowns is consistent with a model of pulsed heating due to high magnetic fields. The observed damage is located in the region of high magnetic fields. To calculate these magnetic fields, 3D electrodynamics models of the couplers were...