A pixellated grating array using photoelectrochemical etching on a GaAs waveguide

We have demonstrated and evaluated a grating array outcoupler fabricated by photoelectrochemical (PEC) etching, a manufacturable and practical approach for fabrication of grating-based III-V semiconductor waveguide devices. An array of submicron period gratings was etched into photolithographically delineated areas in a single PEC step. The fabricated devices are: 10-μm wide rib waveguides with 0.35-μm first-order outcoupling gratings; and 10-μm wide rib waveguides with 10 μm×10 μm pixellated areas of gratings. Device characterization demonstrates the effectiveness of outcoupling grating fabrication using PEC and that the pixellated grating outcoupler is an effective and simple means of generating an optical beam array.