Fusion splicing of polarization preserving fibers

A novel technique is developed to detect any principal axis misalignment of polarization preserving fiber. The technique is based on measurement of reflect-returned power for the fiber oputput endface that is depolarized by the birefringence of the fiber. It is confirmed theoretically and experimentally that principal axis alignments of 0 and 45 degrees can be successfully made only by minimizing and maximizing the monitoring level, respectively. On the basis of the alignment method, a fusion splicing technique is proposed for polarization preserving fibers. It is confirmed theoretically and experimentally that all principal axes alignment, core axis alignment, and splices loss estimations can be simply and sequentially attained with the present technique. Using the technique, +/-0.5 degree angular alignment resolution and +/-0.05-dB splice loss estimation accuracy are satisfactorily achieved.