Abstract: An optical fiber coupler and its method of use are disclosed. In the coupler a centrally located lens is disposed between the ends of the source and outlet optical fibers, the fibers themselves are formed into the most spacing filling configuration at their ends adjacent the lens, and the lens and fiber ends are secured with an adhesive. The lens, fibers and adhesive will all have substantially equivalent indices of refraction so that there is no excessive light attenuation through the lens and adhesive layers. The optical fibers may be glass or polymer, be single or multiple mode, and have uniform, step or graded refractive indices. A wide variety of combinations of fiber bundles, from single fibers to bundles of up to 128 or more fibers, can be coupled through this device. In its method of use aspect, the received fibers are inserted into the sleeve and adhered to the lens with the adhesive, while venting trapped air and excess adhesive.