In non-contact style source couplers, an air gap exists between

the fiber and the lens. This design is more flexible, allowing a

wide range of lens types and focal lengths to be used. The

distance between the fiber and the lens can be adjusted to

compensate the changes in the source wavelengths or to

intentionally defocus the laser beam to prevent arcing in high

power laser to multimode fiber applications. Couplers using GRIN

lenses, achromats, aspheres, fused silica, plano-convex, and bi-

convex lenses have all been made utilizing this design.