Core alignments by a simple local monitoring method

A new simple local monitoring method in core alignments of single-mode fibers is presented. We have investigated cladding-mode leakage light characteristics in fibers coated with different materials. In view of the results of the study, we have developed an arc-fusion splicer with a simple photoreceiver for monitoring the leakage light power. Using the splicer, we have obtained a surprisingly good result of an average splice loss of 0.03 dB with transmitted optical power of only 1 μW at the butt-joint point. This method can be used for final splicings between repeaters in long-haul optical fiber digital transmission systems.