The OptiFocus Lensed Taper from Corning Inc. of Corning, N.Y., focuses light to very small spot sizes farther from the lens, thus avoiding yield loss and a greater amount of light being reflected off the surface. The company says its uniqueness comes from the superior lens performance and proprietary lens design. The mode-field diameter must match that of the device for optimal coupling. Using a proprietary combination of gradient-index and hyperbolic-refractive-lens technologies, the lensed taper couples light between optical fiber and devices that have high divergence angles, such as edge-emitting lasers and InP-based devices. The process fuses a glass rod with a radial gradient index profile to the end of the fiber. A hyperbolic surface is formed onto the end of the rod by melting the glass. Precise control of the gradient-index glass length and hyperbolic lens shape defines the beam size and working distance. The taper can be formed on the end of any single- or multimode fiber. The device provides a small mode-field diameter and a working distance that is more than three times that of other products. Lens designs can be customized to the device requirements. Other benefits include high coupling efficiency, high return loss, low reflection from the front of the lens, and precise and repeatable beam characteristics. The OptiFocus also allows more flexibility in packaging design.