Innovation in optical fibers and cables enabling scaling optical network capacity

Optical fiber cables with increased capacity are required to meet the bandwidth demand in almost all segments of optical networks. The paper discusses optical fiber and cable innovations for increasing cable capacity in data center interconnect and submarine applications. For the data center interconnect applications, the fiber densities in cables are constrained by the microbending sensitivity of the optical fiber, that manifests itself through the attenuation increase during the thermal cycling performance. Different optical fiber and cable parameters impacting microbending sensitivity are discussed. A fiber-cable frame-work is presented that predicts the fiber densities that are achieved for different combinations of fiber attributes. For submarine applications, use of multicore optical fibers (MCF) are discussed for achieving cable capacities of 1 Pb/s or higher. Heterogeneous two-core MCF designs are disclosed which have resulted in attenuation of ≤ 0.15 dB/km, counterpropagating crosstalk ≤ -50 dB/100 km, average splice loss of less than 0.4 dB and PMD of less than 0.1 ps/km^1/2. The heterogeneous-core designs result in good crosstalk performance both in cable and on a shipping spool. Heterogenous-core fibers having different core-element radius are also attractive for core identification as they result in marker-core elimination. Four-core MCF designs are also disclosed that result in low loss and cable capacity of 2 Pb/s.