Huawei Technologies Co. Ltd. has confirmed it has shipped single-carrier 100Gbit/s coherent optical transmission technology to a commercial customer.

That customer is KPN Telecom NV (NYSE: KPN), which Huawei announced during last week's CommunicAsia show. A Huawei spokeswoman confirmed the single-carrier part in an email to Light Reading. (See Huawei Deploys 100G for KPN.)

"Single-carrier" refers to putting all 100Gbit/s on one wavelength. Some systems, including the 100Gbit/s developed by Nortel Networks Ltd. and being shipped by Ciena Corp. (NYSE: CIEN), split the traffic onto two wavelengths that carry 50 Gbit/s apiece and squeeze into one ITU grid assignment. That means they're treated as one "wavelength" in a DWDM network, but the process does require two lasers.

The only other vendor to have announced a single-carrier 100Gbit/s product is Alcatel-Lucent (NYSE: ALU), which launched a year ago. At the time, Heavy Reading analyst Sterling Perrin noted that carriers are indeed waiting for a single-carrier option -- so, you could argue the distinction really does matter. (See Analyst: AlcaLu's 100G Game-Changer.)

Huawei joins AlcaLu, Ciena and MRV Communications Inc. (Nasdaq: MRVC) in shipping 100Gbit/s systems conforming to the Optical Internetworking Forum (OIF) framework, the accepted convention based on a modulation scheme of dual polarization, quadrature phase-shift keying (DP-QPSK). (See 100G Watch: Another DWDM Contender.)

Pretty much everybody in optical networking is expected to have OIF-compliant 100Gbit/s systems announced, if not deployed, by mid-2012.

But wait, there's more. Huawei tells Light Reading it's also delivered a less expensive dual-carrier 100Gbit/s technology to China Telecom Corp. Ltd. (NYSE: CHA), another deployment announced last week. (See China Telecom Deploys Huawei's 100G.)

That technology, shipping since late 2010, doesn't use coherent detection, but is based on a modulation scheme called symmetric DQPSK, analyst Sterling Perrin wrote in a March report titled "100Gbit/s Transport: Forecast Analysis."

Coherent detection requires high-end electronics, and at 100 Gbit/s, the earliest vendors have had to develop those chips on their own. So, by leaving coherent detection out of sDQPSK, Huawei could get the technology out more quickly and keep the cost down. Perrin's report notes that sDQPSK uses pieces that were already available from Huawei's 40Gbit/s suppliers.

(For more coverage of CommunicAsia, see the Light Reading CommunicAsia site.) — Craig Matsumoto, West Coast Editor, Light Reading