Twin-core fiber design and preparation for easy splicing

Several methods of preparing twin-core fibers (TCFs) that can be easily spliced to standard single-core single-mode fiber are proposed. Unlike the conventional TCF preparation methods that are used to fabricate a TCF with both cores placed symmetrically with respect to the fiber axis, these methods result in twin-core fibers that have one core in the fiber center. Experimental results obtained with the TCF fabricated by using one of the designs are presented.