We present the theoretical simulation and experimental results of a slot waveguide structure and a strip-to-slot waveguide coupler implemented in the GaAs/AlGaAs system. Although there have been many demonstrations of slot waveguides in silicon and silicon nitride, there has been limited work devoted to demonstrating this device in a III-V semiconductor material system. Implementing slot waveguides in a III-V material system such as GaAs/AlGaAs would provide the advantage of monolithic integration with active photonic components such as lasers and photodetectors. Slot waveguides have been widely studied for biosensing applications because of their ability to confine a significant portion of the electric field in an air slot, thereby increasing the spatial overlap of the optical mode with surrounding analytes. Monolithic integration in the III-V system would therefore enable the development of photonic lab-on-a-chip biosensing platforms. Due to the low refractive index contrast in the GaAs/AlGaAs relative to that of the silicon-on-insulator (SOI) material system, AlGaAs material composition, epitaxial waveguide layer thicknesses, and slot etch depth must be optimized to realize low-loss propagation in the slot waveguide. Specifically, we demonstrate elevated and suspended slot waveguide structures. The first is formed by etching into the underlying AlGaAs cladding layer and the second is formed by etching away the underlying AlGaAs cladding. These structures are fabricated and tested at a wavelength of 1550 nm.Ope
