- Compact aplanatic concentrators can reconstitute the flux of a near-field ultrabright incoherent light source and couple it into an optical fiber. Performance near the thermodynamic limit for light transfer can be realized, even at high numerical aperture. The prospect of arc-discharge lamps as alternatives to lasers for many surgical fiber-optic procedures motivate this investigation. LED-fiber and fiber-fiber coupling constitute additional applications. The contours of these achromatic mirrored systems are analytic functions, which facilitates rapid surveying of a wide range of design options.