CWDM8 MSA aims to fast-track 400G interfaces

Created September 28, 2017
Robert_Blum_IntelNews and Business

A new multi-source agreement (MSA) group was announced at the ECOC show to speed up the market introduction of 400-gigabit client-side optical interfaces. The CWDM8 MSA is described by its members as a pragmatic approach to provide 400-gigabit modules to coincide with the emergence of next-generation switches in 2018.

The CWDM8 MSA uses eight wavelengths separated using coarse wavelength-division multiplexing (CWDM). The scheme is being promoted as a low-cost alternative to the IEEE 803.3bs 400 Gigabit Ethernet Task Force’s 400-gigabit eight-wavelength specifications, and as a lower risk approach than the newly formed 100G Lambda MSA based on four 100-gigabit wavelengths.

“The 100G Lambda has merits and we are also part of that MSA,” said Robert Blum, director of strategic marketing and business development at Intel’s silicon photonics product division. “We just feel the time to get to 100-gigabit-per-lambda is really when you get to 800 Gigabit Ethernet.”

Intel is one of the 11 founding companies of the CWDM8 MSA.

The CWDM8 MSA will develop specifications for 2km and 10km links. And by using wavelengths spaced 20nm apart, no temperature control of the lasers will be required.

A key design aspect of the CWDM8 MSA is that it does not use 4-level pulse-amplitude modulation (PAM-4). Instead, 50-gigabit non-return-to-zero (NRZ) signalling is used for each of the eight wavelengths. The MSA will use the standard CDAUI-8 8×50-gigabit PAM-4 electrical interface. Accordingly, a retimer chip will be required inside the module to translate the input 50-gigabit PAM electrical signal to 50-gigabit NRZ. Several companies are developing such a chip, said Blum.

Customers are telling Intel that they need 400-gigabit duplex-fibre optical modules early next year and that they want to have them in production by the end of 2018.

The founding members of the CWDM8 are Accton, Barefoot Networks, Credo Semiconductor, Hisense, Innovium, Intel, MACOM, Mellanox, Neophotonics and Rockley Photonics.

By Roy Rubenstein

See also:

 Press release: CWDM8 MSA group forms to support deployment of 400G 2km and 10km optical links in data centers

Gazettabyte: The CWDM8 MSA avoids PAM-4 to fast-track 400G

Optical Connections: Multi-source agreement paves the way for 4-wavelength 400-gigabit modules

Multi-source agreement paves the way for 4-wavelength 400-gigabit modules


This article was written
by Roy Rubenstein

is the editor of and has been researching and writing about the telecom and semiconductor industries for over 20 years.