100-300 m 500 m 2 km 10-20 km 40 km
FIGURE 1: Shipments of 100 GbE by reach, 2010-2023. Source: LightCounting Ethernet Forecast - September 2018.
48 I ICT TODAY
100 GbE by Reach - Shipments
2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023
Figure 1 shows LightCounting’s prediction for
strong 100 GbE growth from 2018-2023 for both
MMF-based 100 to 300 m reach and SMF-based 2 km
reach solutions. Both MMF and SMF solutions are
expected to grow significantly.
The predicted uptake of 100 GbE MMF modules,
driven by the introduction of 100 Gb/s switch links and
later by the development of 100 Gb/s servers, shows the
need for 400 GbE MMF modules. New Ethernet standards
are being developed to support this demand.
400GBASE-SR16, an MMF-based 16-fiber pair
solution for 400 Gb/s applications has been standardized
but is not expected to ship in large volumes. Two new
400 Gb/s multimode solutions were standardized
in January 2020. In 2018, the IEEE P802.3cm 400 Gb/s
over Multimode Fiber Task Force was created, tasked
with developing standards for 400GBASE-SR4.2 and
400GBASE-SR8. These solutions are based on 50 Gb/s
lanes on OM3, OM4, and OM5.
Furthermore, 400GBASE-SR4.2 is the first multimode
Ethernet standard that utilizes WDM and takes
advantage of OM5 fiber’s wideband capability. In this
solution, two wavelengths or lanes are used to transmit
100 Gb/s over each fiber pair. Four MMF pairs used
with two wavelengths/fiber leads to the new designation
400GBASE-SR4.2 where 400GBASE defines the 400
Gb speed, SR denotes Short Reach, and the 4.2 describes
the number of fiber pairs, followed by the number of
wavelengths used. These modules have been introduced
in the market and are expected to be widely deployed
in enterprise and data center networks. SR4.2 operates
over two wavelengths at 850 nm and 910 nm just like
currently popular 40 Gb and 100 Gb BiDi modules.
Moreover, 400GBASE-SR8 operates at 850 nm over
8 pairs of MMF, each pair carrying 50 Gb/s at 850 nm.
The 400GBASE-SR8 transceivers are commercially
available and have been adopted by some large
hyperscale customers.