Throughput optimization in hybrid C-C plus L-band elastic optical networks enabled by hybrid modulation and wavelength/modulation conversion

Elastic optical networks (EONs) have been proposed to address the increasing needs of future communications, yet the capacity of these networks is expected to run out. Evolving the current C-band system to use the C+L-band is a costly and time-consuming solution. This paper presents a stopgap solution to meet the increasing communication needs in the short term by exploiting hybrid fused C- and L-band transmission before the full evolution is achieved. The proposed physical-layer-impairments-aware high spectral efficiency (PAHSE) algorithm jointly applies time domain hybrid modulation (TDHM) and modulation and wavelength conversion techniques and uses accurate models to estimate physical layer impairments for the C- and C+L-band links. The hybrid network scheme converts C-band signals to L-band at the regenerator nodes, which increases the system throughput. The proposed PAHSE algorithm assigns the highest spectral efficiency to each transparent segment of each traffic request while satisfying the quality of transmission requirements. Simulations are conducted on two network topologies, one of large diameter and the other highly connected, using several types of traffic that mimic demands expected in future communication scenarios. Compared to the benchmark, the proposed network system and algorithm result in much higher network throughput, up to a 120% increase in the sum bit rate in the NSFNET-24 topology, thus obviating the urgent need for full C+L deployment.(c) 2023 Optica Publishing Group