2012: The year of 100 Gigabit transponders
Tuesday, December 6, 2011 at 9:52AM Oclaro has detailed its 100 Gigabit coherent optical module that will be available from the second quarter of 2012. The MI 8000XM, a 5x7-inch 100 Gigabit-per-second (Gbps) transponder, uses NTT Electronics' (NEL) analogue-to-digital converter/ digital signal processor (DSP) ASIC at the receiver that compensates for transmission impairments.
“The world is moving to coherent, there is no question about that”
Per Hansen, Oclaro
The 100Gbps module expands the company's coherent offerings. Oclaro is already shipping a 40Gbps coherent module. “The world is moving to coherent, there is no question about that,” says Per Hansen, vice president of product marketing, optical networks solutions at Oclaro.
Why is this significant?
Having a selection of 100Gbps long-haul optical modules will aid the uptake of high-capacity links in the network core. Opnext announced in September its OTM-100 100Gbps coherent optical module, in production from April 2012. And at least one other module maker has worked with ADVA Optical Networking to make its 100Gbps module, a non-coherent design.
The 100Gbps coherent optical modules will enable system vendors without their own technology to enter the marketplace. It also presents those system vendors with their own 100Gbps technology - the likes of Alcatel-Lucent, Ciena, Cisco and Huawei - with a dilemma: do they continue to evolve their products or embrace optical modules?
“These system vendors have developed [100Gbps] in-house to have a strategic differentiator," says Hansen. "But with lower volumes you have a higher cost.” The advent of 100Gbps modules diminishes the strategic advantage of in-house technology while enabling system vendors to benefit from cheaper, more broadly available modules, he says.
What has been done
Oclaro is still developing the MI 8000XM module and has yet to reveal the reach performance of the module: “We want to do many more tests before we share,” says Hansen. The module will meet the Optical Internetworking Forum's (OIF) 100Gbps module maximum power consumption limit of 80W, he says.
The OIF 100 Gigabit module architecture
The NEL DSP chip is the same device that Opnext is using for its 100Gbps module. “A partnership agreement and sourcing arrangement with NEL allows us to come to market with what we think is a very good product at the right time,” says Hansen.
The DSP uses soft-decision forward error correction. Opnext has said this adds 2-3dB to the optical performance to achieve a reach of 1500-1600km before regeneration.
In 2010 Oclaro announced it had invested US $7.5 million in Clariphy Communications as part of the chip company's development of its 100Gbps coherent receiver chip, the CL10010. As part of the agreement, Oclaro will get a degree of exclusivity as a module supplier (at least one other module maker will also benefit).
ClariPhy has said that while it will not be first to market with a 100Gbps ASIC, the CL10010 will be a 28nm CMOS second-generation chip design. To be able to enter the market with a 100Gbps module next year, Oclaro adopted NEL's design which exists now.
Next
Hansen says that the MI 8000XM, which uses a lithium niobate modulator, is designed to achieve maximum reach and optical performance. But future 100Gbps modules will be developed that may use other modulator technologies and be optimised in terms of power or size.
Hansen is also in no doubt that the next speed hike after 100Gbps will be 400Gbps. Like 100Gbps, there will be some early-adopter operators that embrace the technology one or two years before the consensus.
Such a development is still several years away, however, since an industry standard for 400Gbps must be developed which is only expected in 2014 only.
Reader Comments (3)
What are the limitations of the coherent module? How much chromatic dispersion can it tolerate for 100G? Will it compensate non-linear effects also?
Opnext's response is as follows:
Its coherent module is designed to operate in networks without chromatic dispersion compensator modules (DCMs) so that the chromatic-dispersion tolerance of the 100 Gigabit coherent module is 'very high' to accommodate that.
The company says it will release more detailed information later in 2012.
And here is Oclaro's response:
We have not released specs on the module yet. However, it is reasonable to expect that the dispersion compensation range will accommodate the vast majority of use cases.
These modules are designed to eliminate in-line dispersion compensation entirely and facilitate richer and more dynamic optical mesh networks.
A general question about compensation of non-linear effects is difficult to answer briefly. We design these solutions to provide the best possible transmission performance and have unique expertise in that area.
We are happy to discuss performance in much more detail with customers individually. I can be reached on per.hansen@oclaro.com and will be happy to direct requests for information to the appropriate people in Oclaro.