The many paths to 400 gigabits
The race is on to deliver 400-gigabit optical interfaces in time for the next-generation of data centre switches expected in late 2018.
The industry largely agrees that a four-wavelength 400-gigabit optical interface is most desirable yet alternative designs are also being developed.
Optical module makers must consider such factors as technical risk, time-to-market and cost when choosing which design to back.
Until now, the industry has sought a consensus on interfaces, making use of such standards bodies as the IEEE to serve the telecom operators.
Now, the volumes of modules used by the internet giants are such that they dictate their own solutions. And the business case for module makers is sufficiently attractive that they are willing to comply.
Another challenge at 400 gigabits is that there is no consensus regarding what pluggable form factor to use.
“There is probably more technical risk in 400 gigabits than any of the historical data-rate jumps we have seen,” says Rafik Ward, vice president of marketing at Finisar.