Monitoring method for axis alignment of single-mode optical fiber and splice-loss estimation

Abstract

A new method for core-axis alignment and precise splice-loss estimation for single-mode optical fibers is presented. By using a differential interference contrast microscope, we can achieve core-axis alignment with an offset below 0.3 microm, which results in a butt-joint loss increase of 0.04 dB compared with that obtained by alignment using a conventional optical monitoring method. Furthermore, splice-loss estimation with a precision of 0.05 dB is attained for a low-loss region without using an index-matching liquid.