Optical coupling between a self-assembled microsphere grating and a rib waveguide

The fabrication of a linear array of self-assembled polystyrene microspheres side coupled to a rib waveguide was discussed. A side-coupled rib waveguide microsphere grating was demonstrated using a simple low-cost self-assembly process. It was shown that the optical coupling between the lateral evanescent field and the periodically perturbed effective refractive index alongside the waveguide results in a transmission stopband at the Bragg wavelength. It was predicted that with improved sphere diameter control and more uniform assembly, a deeper and narrower response will be achieved.