Coriant CloudWave Optics promises flexible optical transport, greater reach

Software-defined networking (SDN) and optical transport systems vendor Coriant has announced Coriant CloudWave Optics, a range of software-programmable optical layer capabilities designed to pair with its Coriant Dynamic Optical Cloud offering to promote flexible service provisioning via a variety of optical modulation formats. Field trials have demonstrated that CloudWave Optics can support greater reach for higher-order modulation formats such as 16QAM than competitive approaches, according to a Coriant source.

Available in the second half of this year, Coriant CloudWave Optics features software-programmable line-side modulation (including DP-QPSK, 8QAM, and 16QAM), tunable spectrum allocation, and adjustable channel frequency flexibility, says Uwe Fischer, Coriant's CTO. Fischer acknowledges that Coriant isn't the first company to offer a choice of software-programmable optical modulation formats (see, for example, "Infinera FlexCoherent to enable variable 40G/100G optical modulation formats"). However, he believes Coriant can differentiate its approach via lower power consumption (in part through the use of a dual-core DSP ASIC that requires less power than approaches reliant on multiple single-core ASICs) as well as the ability to transmit these modulation formats on an ITU-T 50-GHz grid.

Of course, the technology is designed to work well in a superchannel environment that leverages flexible-grid ROADMs as well. Fischer says that Coriant has a trick up its sleeve for these deployments too: the ability to squeeze subchannels onto a grid slightly narrower than the typical 37.5 GHz. This narrower spacing enables superchannels to be switched without having to allot guardbands, Fischer says.

Field trials have demonstrated the CloudWave Optics capabilities can improve the reach of 16QAM. Fischer points to a trial conducted with TeliaSonera International Carrier that saw the partners transmit a 400-Gbps 16QAM signal via in-place Coriant hIT 7300 packet-optical transport platforms across 1,634 km on a route between Paris, Luxembourg, and Frankfurt without recourse to Raman amplification.

The technology also was used in the recently reported 38.4-Tbps field trial on the Orange network as part of the SASER research program (see "Orange sends 38.4 Tbps over 762 km"). There, the CloudWave Optics capabilities also supported the use of 32QAM modulation (32 Tbps) and 64QAM (38.4Tbps) over 762 km, this time with Raman amplification.

Despite the 16QAM achievement, Fischer and his colleagues at Coriant don't expect the modulation format to see widespread use, particularly in the short term, due to the 500-km reach limitations it imposes (see, for example, "Flexi-rate optical interfaces go mainstream" for more on this). Fischer is much more bullish on 8QAM, which will enable per-wavelength data rates greater than 100 Gbps on a wide range of existing networks without having to install regeneration gear. He sees 8QAM supporting around 150 Gbps per carrier, which means 300 Gbps on a two-carrier system.

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