Multicore Process Simplifies Fiber Splicing

A new automated process simplifies the alignment and splicing of optical fibers and can bundle multiplexed fibers consisting of up to 19 cores and up to 19 times the signal-carrying capacity.

Multicore optical fibers — bundles of multiplexed fibers — have many times the signal-carrying capacity of traditional single-core fibers, but their use in telecommunications had been restricted because of the challenge in splicing them together — picture trying to match up and connect two separate boxes of spaghetti so that all of the noodles in each box are perfectly aligned.

“Although the manual way may be good for a skilled operator in a lab environment for research purposes, automation is the only path that can push MCF [multicore fibers] to factories and production lines,” said Wenxin Zheng, manager of splice engineering at AFL and developer of the technique.

In the process, which uses a Fujikura FSM-100P+ fusion splicer, the fibers are stripped and loaded into the splicer, then rotated and imaged with two video cameras so that their cores can be roughly aligned using a pattern-matching algorithm. Next, a pair of corresponding cores in each fiber is finely aligned, as is the cladding around the cores, using a power-feedback method and image processing. Upon alignment, the cores are heat-spliced. The technique offers minimal losses in signal quality across the spliced sections.

The Fujikura FSM-100P+ fusion splicer is used for the automated alignment and splicing of MCF with PC control software developed by AFL. Courtesy of Fujikura Splicer Department.

“To align the multiple cores simultaneously is a big challenge,” Zheng said. “If two fibers to be spliced have random core locations, there is no way to align the entire core.”

However, the component cores of MCFs can be aligned if created using the same design standard, and if the cores are distributed symmetrically in the MCF — such as in a seven-core MCF with one central core surrounded by six cores oriented like the spokes of a wagon wheel.

In that case, Zheng said, “we can fine-align one side-core in an MCF and its cladding at the same time. Based on the geometric specifications of the fiber, the rest of the cores will be automatically aligned.”

The research, titled “Automated Alignment and Splicing for Multicore Fibers,” was presented March 18 at OFC/NFOEC 2013 in Anaheim.

For more information, visit: www.ofcnfoec.org or www.aflglobal.com