The Increasement of 100G Will Drive the Development of 400G

The widespread deployment of 100G Ethernet in data centers and networks is driving the demand for 400G solutions and providing a source of funding for 400G device developments. Those suppliers who have successfully developed competing 100G optical modules and components are expanding 100G while developing lower-cost 100G solutions and introducing 25G, 50G, 200G, 400G and 600G products.

The first 100G Ethernet solution was launched in 2010. Since then, 100G shipments have been slow to grow due to the costly optical module and demand constraints. By 2016, the introduction of 100G QSFP28  will significantly reduce the cost of 100G ports and the migration of the super-large data center to the cloud service has brought huge demand.

As a result, 2017 has been proved to be a "Hockey-stick Effect" year of 100G Ethernet and optical module suppliers are struggling to meet market demand. At this stage, the focus of optical modules and device suppliers is to increase 100G capacity and reduce costs to "cash in" from this wave of demand. The ways to reduce costs include innovative module packaging, silicon photonics, smaller form factor modules such as SFP-DD, and fewer channels / wavelengths.

The first 400G optical module for data centers and enterprises is CFP8 form factor and is being commercialized. The next generation will use QSFP-DD or OSFP. The 100G optical transceivers using DP-QPSK coherent receivers have been widely used in data center interconnection, MAN and Toll networks. The enhanced DSP can now achieve 200G with 16QAM modulation, while the next generation can support 400G and 600G with 64QAM modulation. These developments are critical to meeting the bandwidth needs of the data center.

Currently, nearly 30 suppliers offer QSFP28 modules and active optical cable for 100G data centers and enterprise applications. Many suppliers have also introduced SFP28 modules that support 25G Ethernet to server. Some vendors offer 100G CFP/CFP2/CFP4 and CXP modules. The largest shipments of QSFP28 optical modules are QSFP28 PSM4 and QSFP28 CWDM4 for very large data centers and other applications. The first 200G optical module introduced by manufacturers is QSFP56 and PAM4 coded, or QSFP-DD form factor and two 100G ports.

Data Center interconnection, MAN and long haul systems use DSPs integrated into line card modules or pluggable CFP-DCO modules. Most leading telecom system manufacturers have their own DSP designs. Several companies use DSPs integrated on the line card and pluggable CFP2-ACO modules that contain only analog and optical components. This is a key innovation area for vendors developing next-generation 400 / 600G DSP designs, 200G CFP2-DCO modules and 400G modules. OIF is working on a 400-120-km 400ZR interface standard and Ciena licenses three 400-G-coherent DSP chips to three optical module companies (Lumentum, NeoPhotonics and Oclaro).

Coherent transceivers DSP and Gearbox components, PAM4 PHY and CDR components, optical driver / receiver arrays, and packet optical transport platform components are the key to building these optical modules and line cards. Currently, the latest generation of devices uses 16nm CMOS technology, the next generation of DSP is expected to use 7nm technology. The PAM4 PHY and 50G CDRs enable dual wavelength 100G and four wavelength 200G solutions. Next-generation components will support single-wavelength 100G.

The demand for 100G in the data center and other application markets is very strong. As the cost of modules drops and the production capacity gradually increases to meet the demand, the 100G optical module market in 2018 will be highly competitive. At present, the first solution of 200G and 400G is already available. The industry is currently working to reduce 100G costs by developing higher density 400G and 800G and 1.6Tbit / s solutions. All methods are using advanced coding and modulation methods, especially PAM4 for data centers and enterprises, as well as 16 / 64QAM for Data Center interconnection, MAN and Toll networks. These developments require substantial investment by suppliers, which may lead to further consolidation in the industry.