Taper splice method for single-mode fibers

A low-loss splice method which processes a splice point to a taper shape is investigated for use in subscriber single-mode fiber cables. An average splice loss, taking into account the fiber parameter deviations and radiation loss in the taper portion, is estimated statistically and experimentally. The optimum value of the taper ratio is determined to be 0.55. A new processing method for gradual tapers, by pulling fibers and moving a pair of discharged electrodes, is presented. It is clear that radiation loss due to waveguide metamorphosis is the dominant cause of taper loss, which is influenced by fiber structures. It is also clear that the quick fusion method, with a discharge duration of 1 s, is desirable for the taper splice method. Furthermore, it is confirmed that for splicing two fibers having core eccentricities of 1.5 and ≃0 μm, splice loss can be improved from 0.4 to 0.25 dB by processing the splice point to a taper shape.