Abstract: The demand for optical bandwidth is straining the capacity of cable conduit systems, especially in North America. Network operators are looking to maximize duct capacity by installing the largest possible optical cables that meet performance specifications. In these large cable designs, optical ribbon is used to minimize deployment costs by supporting mass fusion splicing. Design constraints on traditional flat ribbon cable structures have limited the maximum cable capacity to 864 fibers in a 25 mm cable.
Rollable ribbons were developed in Japan to address the design constraints imposed by traditional ribbon structures. The linear array of fibers is intermittently connected by matrix. The intermittent connection breaks the preferential bending of the ribbon structure and allows the use of design rules for a loose fiber or fiber bundle cable while supporting standard mass fusion splicing.
This paper will describe how the rollable ribbon concept allows the doubling of the fiber density of ribbon cables. The cables developed use the loose tube cable structure familiar to North American network operators and installers. Ribbons with standard ribbon marking are grouped in color coded tubes. Dry buffer tubes containing 12 fiber rollable ribbons were developed to replace buffer tubes containing traditional flat ribbons in each tube. The structure meets standard North American performance standards for OSP cable including temperature, water penetration, crush resistance, and coiling. Installation and splicing are consistent with that for legacy ribbon loose tube cable with flat ribbons.