Measurements of Loss Due to Offsets and End Separations of Optical Fibers

Abstract

If fibers are to be coupled together by means of detachable connectors, there is a need to know how much light will be lost by misalignment or axial separation of the fiber ends. Measurements were made of coupling efficiency from one fiber to another versus offset and end separation with and without index-matching liquid between the ends for a single-mode and a multimode fiber at λ = 0.6328 μm. Graphs are presented for offsets as great as 3 radii and for end separations up to 127 μm. Maximum coupling efficiency of 97 percent was obtained, and about 50 percent was obtained with an offset of 1 radius.