A review of optical beamforming techniques is presented. The techniques are subdivided into two broad categories. First, several representative implementations of narrow band, phase-only techniques are summarized. A detailed description of a narrow band architecture realized in our laboratory is presented. The architecture is based on coherent heterodyning of two narrow linewidth Nd:YAG lasers, with a controlled angular beam offset to generate the required microwave phase progression. Second, several representative wideband, true time delay architectures are briefly described. A description of a 'dispersive-prism' based true time-delay technique developed in our laboratory is presented. The results show multi-octave one-dimensional transmit and receive true time-delay beamformer operation, as well as two-dimensional transmit beamformer operation. References: 28
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