Multi-Core vs Hollow-Core Fibers: Technical Study of Their Viability in SDM Power-Constrained Submarine Systems

We study the technical viability of Multi-core and Hollow-core fibers for submarine links considering transceiver limitations and typical power constraints of Spatial Division Multiplexed systems. We discuss the opportunities and challenges these technologies will face to be adopted in the mid and specifically in the long-term. First, Hollow-core fibers exploiting only C and L bands (where amplification technologies are commercially available) are studied. We show that they are not yet competitive with current-state parameters with multi-core fibers. Nevertheless, in very power-constrained scenarios, this fiber would be competitive in certain situations even with 4-core multi-core fiber if its attenuation is reduced and power delivered by the Power Feed Equipment is increased. Then, long-term scenarios are also considered with coupled-core fibers (if MIMO is implemented in the DSP) and Hollow-core fibers with up to 45 THz (if amplification technologies outside the C and L bands become commercially available). We show that at long distances, because of power limitations, this 45-THz potential bandwidth would not allow higher capacities unless the fiber attenuation was reduced below 0.10 dB/km. At these attenuation values, the amplifier number reduction could play an important role in relieving power constraints and therefore allow higher capacities. This article extends our previous work with more realistic parameters to increase the accuracy of the results.