Abstract

High-speed, wide-angle, free-space optical beamsteering by coherent arrays is attractive for applications such as optical interconnects, switching, and displays, but previously proposed uniform arrays radiate undesirable sidelobes in addition to the main lobe. In this work, we show both experimentally and theoretically that sidelobes can be dramatically suppressed by arraying emitters in a non-uniform pattern. Sidelobe suppression in a 12-element reactive-ion-etched GaAs homostructure waveguide array was obtained in close agreement with theory. The optimum spacing is closely approximated by a gradual, linearly-increasing doubling in interelement spacing across the array. A 100-element array of minimum spacing 5 μm, practical with present semiconductor waveguide technology, can attain a 30:1 reduction in sidelobe intensity with a 0.08° FWHM main lobe.

© 1988 Optical Society of America