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100G coherent module market heats up

20 April 2012
Finisar has demonstrated its first 100Gbps coherent transponder, a 5x7-inch module that meets the Optical Internetworking Forum's multi-source agreement (MSA) specification. 

The company joins Opnext and Oclaro, who have already announced 100Gbps coherent module products. Oclaro and Opnext have since announced their intention to merge (see Oclaro-Opnext merger to create new number two components vendor).

"We can take off-the-shelf DSP [digital signal processing] technology and match it with vertically-integrated optics and come up with a module that is cost effective while enabling higher density for system vendors," said Rafik Ward, vice president of marketing at Finisar. "This will start the shift away from the system vendors' proprietary line cards."
Opnext has demonstrated interoperability between its OMT-100 100Gbps coherent module and 100G systems from Fujitsu Optical Systems and NEC. All three solutions use NTT Electronics' (NEL) DSP-ASIC coherent receiver chip.  "For those that use the same NEL modem chip, we can interoperate with each other," said Ross Saunders, general manager, next-gen transport for Opnext Subsystems. Oclaro's MI 8000XM 100Gbps module also uses the NEL DSP-ASIC.
Oclaro has announced that its module is now being manufactured using all its own optical components. This allows the company to control the performance-cost tradeoffs, says Per Hansen, vice president of product marketing, optical network solutions at Oclaro: "This gives us a flexibility we didn't have in the past."  
Finisar is not saying which merchant coherent DSP-ASIC it is using. But like the NEL device, the DSP-ASIC supports soft-decision forward error correction (SD-FEC) which enables the module to achieve a reach of over 2,000km. 
Meanwhile, first 100Gbps modules are starting to be shipped to customers. "We shipped [samples] to four customers last quarter and we are probably going to ship to another four or five by the end of this quarter," said Opnext’s Saunders. Oclaro is sending out its first module samples this month.
By Roy Rubenstein