Infinera's 100G Goes Undersea

Infinera Corp. (Nasdaq: INFN) is announcing Tuesday that it's completed 100Gbit/s subsea trials with Pacific Crossing Ltd. , a subsidiary of NTT Communications Corp. (NYSE: NTT).

The trials, on a 9,500km span from California to Japan, included old and new Infinera systems. Infinera's DTN ran 100Gbit/s Ethernet transmitted on 40Gbit/s optical channels, the first test of the flagship system's 40Gbit/s modules. Infinera also used its FlexCoherent technology for controlling the modulation scheme via software.

On the DTN-X, which hasn't begun production shipments yet, Infinera transmitted 100Gbit/s optical channels using binary phase shift keying (BPSK) modulation and soft-decision Forward Error Correction (FEC).

Why this matters
The modulation schemes and FlexCoherent are really the elements to pay attention to here. The undersea market will be a big part of the splash Infinera wants to make in 100Gbit/s next year, and that's one market where carriers might want to try different modulation schemes -- trading off distance for performance, for example.

So, while the vendor's 100Gbit/s developments are cool and attention-grabbing, this is also part of Infinera's bid to win more undersea business.

NTT, by the way, was announced as an Infinera customer in 2009.

For more
Follow the recent saga of the DTN-X and Infinera's quest for 100Gbit/s. Why, we remember it all just as if it happened last month!

— Craig Matsumoto, West Coast Editor, Light Reading

NoCopper 12/5/2012 | 4:51:19 PM
re: Infinera's 100G Goes Undersea

You cannot compare terrestrial reach figures with submarine figures. Reach of 100G terrestrial is typically limited by OSNR, which is more or less directly related to amplifiers used and ampilifier spacing (typically 80km).

In submarine applications the limiting factor is not OSNR because the amplifiers are low noise and the spacing is much closer (typically 40km). The real challenge in submarine is phase noise and BPSK modulation is pretty robust against phase noise.

rhr 12/5/2012 | 4:51:19 PM
re: Infinera's 100G Goes Undersea Thanks. That makes sense as I learned that the route has some 200 amps (~50km)
rhr 12/5/2012 | 4:51:19 PM
re: Infinera's 100G Goes Undersea Anyone else surprised by the reach demoed here?-áThe advantage of Infinera's OEO approach is that it regenerates automatically. For submarine that is not an option. The story says it is using DP-BPSK so that is 100Gbps using two channels but still, that implies 5,000km for DP-QPSK. Soft decision FEC helps but Opnext's recently announced 100Gbps DP-QPSK OTM-100 module talked of 1,600km and that uses SD-FEC.
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