Spatial optical beam steering with an AlGaAs integrated phased array

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Abstract
A passive spatial light beam deflector based on a channel waveguide phased-array concept is presented. Diffraction gratings patterned by electron-beam lithography couple light into and out of the device. Phasing is achieved electro-optically with indium tin oxide/AlGaAs Shottky junctions. Discrete beam steering is first demonstrated with a 43-element rib waveguide array at an 850-nm wavelength. A sawtooth electrode keeps the device length short and the electrode surface small. Continuous deflection over a ±7.2 mrad range at a 900-nm wavelength is then reported. A set of seven sawtooth and offset electrodes permits addressing any point within this range. The beam has a width of 1.5 mrad, and the maximum modulation voltage is −8.5 V.