Design of thin-film Luneburg lenses for maximum focal length control.
The application of thin-film Luneburg lenses to integrated optical circuits will require accurate control of their focal length to permit the necessary alignment between the various circuit elements. Of particular interest is the design of lenses for application to a silicon-based integrated optical rf spectrum analyzer. This study analyzes the sensitivity of the focal length of Luneburg lenses to thickness variation at the lens center resulting from fabrication process tolerances. It is shown that this sensitivity can be minimized by properly selecting the refractive index of the waveguide material, using a larger focal length and employing a longer optical wavelength.
Colombini
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