Non-Gaussian imaging properties of GRIN fiber lens arrays.

The best focus for a GRIN fiber array is shown to occur when the object and image plane vertex distances are equal, even when neither plane is the proper Gaussian unit magnification plane. This analytical result agrees with previous experimental data. With non-Gaussian imaging, the image plane of best focus for the GRIN array is not coincident with the plane of best focus for the individual gradient-index fibers.