Spherical ball lenses are commonly used for laser collimating and focusing. 1, 2, 3, and 5 mm diameters are available. Larger spheres are easier to handle and ease the sensitivity of translational alignment. However, smaller spheres fit into smaller packages.

Single spherical ball lenses may be used for laser collimation or focusing. Two lenses may be used to enable laser-to-fiber coupling, fiber-to-fiber coupling, or fiber-to-detector coupling. Different diameter spheres may be mixed to produce magnification.

Coupling efficiency for spherical ball lenses can be very high, generally greater than 90%, due to high numerical aperture and simplicity in alignment.