Cost-effective strategies to scale the capacity of regional optical transport networks

The different segments of optical transport networks—including metro, regional, and long-haul—will have to scale to accommodate growing capacity requirements. In metro networks, lower capacity (compared to the other two segments) but more stringent power consumption and interoperability requirements will likely favor the adoption of pluggable coherent interfaces, whereas in long-haul, the best-in-class spectral efficiency of embedded proprietary coherent interfaces is paramount. However, it is less clear which will be the interface type of choice in regional transport networks. This paper compares different strategies to increase the capacity of regional transport networks, which not only exploit the usage of pluggable or embedded interfaces but also enhanced line system solutions, comprising the SuperC-band and hybrid Raman/erbium-doped fiber amplification. Simulation results obtained in two reference regional-sized networks highlight that the utilization of embedded coherent interfaces enables a considerably higher traffic load to be supported over the existing fiber infrastructure, even when the usage of pluggable interfaces is complemented with exploiting the SuperC-band and hybrid amplification. Moreover, for the same transported traffic load, the simulation results also show that embedded interfaces can reduce by up to half the number of line interfaces required, when compared to pluggable interfaces.