AMSTERDAM -- ECOC 2012 -- Like any systems vendor, Infinera Corp. (Nasdaq: INFN) is very keen to discuss any interactions it is having with the Tier 1 carriers and it has peppered the first two days of ECOC with announcements involving Telefónica SA (NYSE: TEF) and Verizon Communications Inc. (NYSE: VZ).

But while the Spanish giant is most definitely a commercial customer -- it's the latest to be using Infinera's DTN-X for a subsea network build -- Verizon is just a test lab buddy and not a signed customer, as Light Reading is repeatedly reminded by anyone within the Infinera camp.

Telefónica first. Having previously deployed the vendor's DTN system in its South American submarine network upgrades, the carrier's International Wholesale Services business is now deploying Infinera's DTN-X platform on its Sam-1 subsea network, which connects various Latin American countries (including Brazil, Argentina, Chile, Peru, Ecuador, Guatemala, Colombia and Puerto Rico) with the U.S. (See Telefonica Int. Deploys Infinera's DTN-X.)

The DTN-X is the vendor's latest high-capacity platform that enables operators to provision 500Gbit/s so-called superchannels over long distances, and so has been attracting attention in the submarine networks sector. (See Infinera Intros DTN-X, Pacnet, Infinera Demo 500G Super-Channels, Infinera's 100G Goes Undersea and Infinera Unleashes Coherent 100G.)

All the same, the vendor is excited about what it has been doing with Verizon, the U.S. Tier 1 operator that is not currently among Infinera's reference commercial customers (in case that wasn't clear).

The duo have been testing the polarization mode dispersion (PMD) performance of the vendor's 500Gbit/s photonic integrated circuits (PICs) and claim to have achieved a new record for real-time PMD compensation. (See Infinera Tackles PMD With Verizon.)

PMD is a big deal for network operators, as PMD can wreak havoc with optical signals at speeds beyond 10 Gbit/s. As speeds and PMD rates increase, so transmission distances decrease. So higher PMD compensation rates mean greater transmission distance at high speeds, and that, in turn, translates into greater operational efficiencies.

Not only that, points out Geoff Bennett, Infinera's director of solutions and technology marketing, but greater PMD compensation rates also mean that older fiber previously not suitable for higher speeds (40 Gbit/s and 100 Gbit/s) could potentially be considered for use, so increasing the volume of sunk fiber plant for those speeds. (For more on this view, check out Bennett's blog on the topic.)

Infinera isn't the only vendor tackling PMD compensation, of course: Ciena Corp. (NYSE: CIEN)'s WaveLogic 3 chip, for example, boasts "additional enhancements in PMD compensation [that ensures] better performance in existing networks with non-optimal fiber conditions." (See Ciena Pushes Ahead to 400G.)

— Ray Le Maistre, International Managing Editor, Light Reading