Beam Control for Optical Phased Array Transceivers

ABSTRACT: Building on Phase I research that demonstrated the feasibility of target-based phasing for phased array beam control, the proposed Phase II research consists of analysis and a laboratory experiment. The four key topics of the research are phasing at the target, correcting stair mode (also known as array tilt), imaging the target with high resolution, and correcting beam overlap errors on the target. The Phase II experiment is designed to address these four issues in the laboratory, validating the research performed in Phase I and Phase II. The phasing approach, combined with a technique for array tilt correction, can correct all beam piston errors at the target. Moreover, the phase calculations also estimate the speckle field due to reflection of the high energy lasers off the target, allowing for high-resolution speckle imaging of the target in the area of the aim point. The research will also determine if the phasing measurements contain information about beam overlap errors on the target that can be used to correct such errors. This effort is performed in conjunction with AFIT, and will enhance their work in the area and provide partial support to at least one Ph.D. candidate. BENEFIT: The anticipated benefit from this research is the experimental validation of beam control techniques for phased array transceivers. The technology developed in this research will allow phased arrays to achieve their primary design goal of phasing an array of laser beams at a target. As such, the technology is critical in the development of phased arrays. The primary commercial application of this technology will be in high energy laser (HEL) phased array weapons, in which it will be a central component. The technology also produces image data that are useful in HEL beam control as well as active imaging applications. A secondary commercial application exists in active imaging.