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Comparison of optical-waveguide lens technologies

Various materials, lens structures, and processes are examined relative to the lens requirements of an RF spectrum-analyzer implemented through the use of an integrated-optics format. Factors which distinguish optical-waveguide lenses and reflectors from conventional imaging lens systems are enumerated. It is concluded that a thin-film Luneburg lens is the most viable planar approach based upon the use of oxides and, when high refractive-index materials must be employed, the spherical depressed geodesic becomes a feasible alternate.