Multicore optical fibers could be next-gen PON solution

The number of optical fibers needed for access networks using passive optical network (PON) architectures is increasing demand for high-density fiber cables. An interesting solution to this congestion could be multicore fibers from OFS Laboratories.

Jan 1st, 2012
Multicore optical fibers could reduce congestion on passive optical networks
Multicore optical fibers could reduce congestion on passive optical networks

The number of optical fibers needed for access networks using passive optical network (PON) architectures is increasing demand for high-density fiber cables. An interesting solution to this congestion could be multicore fibers from OFS Laboratories (Somerset, NJ). With an outer-glass cladding diameter of 130 μm (slightly larger than conventional 125-μm-cladding-diameter communications fiber), a fiber containing seven individual cores has successfully transmitted seven upstream 1310 nm and seven downstream 1490 nm signals at 2.5 Gbit/s, each over distances of 11.3 km.

Designed for singlemode operation, the fiber has seven 8-μm-diameter fiber cores arranged in a 38 μm core-to-core pitch hexagonal array. The 130 μm clad fiber is acrylate-coated to a final outside diameter of 250 μm. Attenuation for the center core is 0.39/0.30 dB/km at 1310/1490 nm, and average attenuation for the six outer cores is 0.41/0.53 dB/km at 1310/1490 nm. Maximum crosstalk—an extremely important parameter for data transmission—is less than -38/-24 dB at 1310/1490 nm, more than adequate to meet PON requirements. To couple the multicore fiber to seven individual fibers, a special tapered multicore-fiber connector was developed by tapering and fusing the fibers to a dimension that matches the multicore fiber structure, achieving average splice loss values of 0.10 dB, comparable to conventional singlecore fibers. Contact Benyuan Zhu atbzhu@ofsoptics.com.

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