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

Coupling of glass fibers, end to end, for transmitting optical signals requires critical alignment at each coupling point. Coupling can be accomplished by permanently fusing the fibers together, 1 by using permanently bonded sleeves, or by using detachable connectors. This paper presents experimental data for the coupling efficiency of light from one fiber end into another as a function of offsets and axial separation which will be present in detachable connectors and to a lesser extent in fused joints and sleeve joints. Measurements of coupling efficiency versus end separation and translation were made and plotted for a multimode fiber with core diameter of 10.8 nm and a single-mode fiber with a core diameter of 3.7 urn* Several people 2 ' 3 ' 4 have studied the problem of launching efficiency from a Gaussian beam into a fiber, both theoretically and experimentally. A comparison will be made between the theory and our experimental data. * The 10.8-/xm core fiber was manufactured by DeBell and Richardson, Inc., of Ilazardville, Connecticut, and the 3.7-^m core fiber was made by Corning Glass Co. 3159