With a rapidly expanding digital landscape, the need for energy efficient network infrastructure is more important than ever. Optimising energy consumption in telco networks is critical – Salumanus’ Łukasz Bogdanik explores the energy efficiency advancements of coherent modules.
GSMA research shows the telecom industry’s power use at 2-3% globally. While 5G is 90% more energy efficient, its expansion may spike energy usage due to network densification. Optical modules adapt, becoming smaller and more power efficient.
Miniaturisation and design
A notable trend in network infrastructures is the shrinking size of optical modules. Operators have moved from CFP to QSFP-DD, cutting power by half and boosting speed fourfold, now aiming for 400 G solutions under 8W.
Advancements in optical module efficiency result from more than just MSA standard changes. Semiconductor innovations like InP or SiP allow deeper integration of module components. Previously, lasers, amplifiers, modulators, drivers, and CDR systems were separate.
Leveraging these new semiconductor materials and processes, many of these functionalities are now seamlessly integrated into a singular, multifunctional system constructed on a unified semiconductor structure. This integration not only significantly enhances the transmission parameters of these systems but also reduces power consumption compared to systems comprising discrete elements.
Aggregation for higher bitrates
Aggregating traffic for higher bitrates is made possible by the introduction of new-generation modules with increased bit rates, enabling the consolidation of traffic from older modules with lower bit rates. To illustrate, consider the task of concentrating 128 100 G links. In the first scenario, installing four switches, each featuring 32 slots of 100 G ports and consuming around 600 W results in a cumulative power consumption of approximately 2400 W. Adding the power usage of 128 QSFP28 LR4 optical modules brings the total power consumption to 2850 W.
Alternatively, in the second scenario, employing a switch equipped with 32 slots of QSFP-DD ports leads to a power consumption of 1300 W for the switch, and with 32 slots of 400G QSFP-DD LR4 modules, the total power consumption is 1550 W. Functionally equivalent, the latter solution, utilising a switch supporting 400 G throughput, yields a notable 45% energy savings and reduces the rack cabinet space requirement by four times, offering additional cost-effectiveness.
Coherent modules for access networks
In locations requiring the aggregation of traffic from densely deployed antennas, directing it to higher network levels often involves employing 10 G DWDM optical modules, with aggregated channels achieving higher throughputs. Assuming the establishment of 10 such connections, resulting in a total transfer of 100 Gb, the power consumption for this aggregated link amounts to 30 W.
However, the sustainable multiplication of such aggregations becomes impractical given the swiftly escalating volume of traffic in this network segment. The QSFP28 interface is a module boasting a 100 G bit rate, utilising coherent signal modulation, and remarkably consuming only 5.5 W. This coherent 100 G and 5.5 W module can seamlessly integrate into the ports of existing switches and routers at the network’s edge, eliminating the need for replacement. With this solution, we achieve the transmission of every gigabit of information with a remarkable 63% reduction in energy consumption compared to a set of 10 x 10G connections.
Trends like miniaturisation, semiconductor strategies and aggregation can make a real impact in the overall energy efficiency of network infrastructures. By embracing innovative solutions in optical modules, businesses can not only navigate the energy challenges effectively but also contribute to a more sustainable and greener future.
