The market opportunity for linear drive optics

A key theme at OFC earlier this year that surprised many was linear drive optics. Its attention at the optical communications and networking event was intriguing because linear drive - based on using remote silicon to drive photonics - is not new.

Scott Wilkinson

"I spoke to one company that had a [linear drive] demo on the show floor," says Scott Wilkinson, lead analyst for networking components at Cignal AI. "They had been working on the technology for four years and were taken aback; they weren't expecting people to come by and ask about it. "

The cause of the buzz? Andy Bechtolsheim, famed investor, co-founder and chief development officer of network switching firm Arista Networks and, before that, a co-founder of Sun Microsystems.

"Andy came out and said this is a big deal, and that got many people talking about it," says Wilkinson, author of a recent linear drive market research report.

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400-gigabit coherent modules finally hit their stride

NeoPhotonics discusses 400-gigabit coherent modules, the move to 130-gigabaud symbol-rate optical components and a company tunable laser milestone.

NeoPhotonics’ 400ZR pluggable optical modules are now available and will ship in volume from the autumn.

“The QSFP-DD and OSFP 400ZR [optical modules] have passed qualification tests and we are engaged in numerous customer qualifications around the world,” says Ferris Lipscomb, vice president of marketing at NeoPhotonics.

Ferris Lipscomb

400ZR modules implement the OIF’s 400-gigabit standard to connect directly equipment in data centres up to 120km apart without needing separate dedicated dense wavelength-division multiplexing (DWDM) optical transport equipment. The first 400ZR modules will be used by data centre operators.

But coherent pluggables support longer-reach modes. These may be interoperable if implementing the OpenZR+ multi-source agreement (MSA) or when delivering custom optical performance that are referred to as ZR+ modules.

NeoPhotonics has reported that its 400-gigabit coherent QSFP-DD when operated as a ZR+ module can achieve an 800km reach.

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II-VI shrinks an optical line system into an OSFP module

II-VI has developed an optical line system that fits inside a pluggable module. 

The advent of coherent pluggable modules implementing the 400ZR standard allows switches and routers to be linked across separate data centres. Now, with a pluggable optical line system, a dedicated line-system platform is no longer needed to send the 400ZR signals over a fibre. 

Sanjai ParthasarathiIn turn, the network operating system on the switch manages the optical line system directly such that a separate optical management software layer is no longer needed.

“We have shrunk an entire pizza-box line system into a small pluggable,” says Sanjai Parthasarathi, chief marketing officer at II-VI.

Indeed, one customer refers to the II-VI pluggable product - dubbed the OSFP-LS - as a ‘zero-rack-unit’ platform.

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Companies gear up to make 800 Gig modules a reality

Nine companies have established a multi-source agreement (MSA) to develop optical specifications for 800-gigabit pluggable modules.

Maxim Kuschnerov

The MSA has been created to address the continual demand for more networking capacity in the data centre, a need that is doubling roughly every two years. The largest switch chips deployed have a 12.8 terabit-per-second (Tbps) switching capacity while 25.6-terabit and 51-terabit devices are in development. 

“The MSA members believe that for 25.6Tbps and 51.2Tbps switching silicon, 800-gigabit interconnects are required to deliver the required footprint and density,” says Maxim Kuschnerov, a spokesperson for the 800G Pluggable MSA.

A 1-rack-unit (1RU) 25.6-terabit switch platform will use 32 such 800-gigabit modules while a 51.2-terabit 2RU platform will require 64.

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Arista adds coherent CFP2 modules to its 7500 switch

Arista Networks has developed a coherent optical transport line card for its 7500 high-end switch series. The line card hosts six 100 gigabit CFP2-ACO (analogue coherent optics) and has a reach of up to 5,000 km.

Martin Hull

Several optical equipment makers have announced ‘stackable’ platforms specifically to link data centres in the last year.

Infinera’s Cloud Xpress was the first while Coriant recently detailed its Groove G30 platform. Arista’s announcement offers data centre managers an alternative to such data centre interconnect platforms by adding dense wavelength-division multiplexing (DWDM) optics directly onto its switch. 

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Interconnection networks - an introduction

Part 2: Data centre switching primer to provide some background as to what Rockley Photonics is doing.    

Source: Jonah D. Friedman

If moving information between locations is the basis of communications, then interconnection networks represent an important subcategory. 

The classic textbook, Principles and Practices of Interconnection Networks by Dally and Towles, defines interconnection networks as a way to transport data between sub-systems of a digital system.

The digital system may be a multi-core processor with the interconnect network used to link the on-chip CPU cores. Since the latest processors can have as many as 100 cores, designing such a network is a significant undertaking.

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Arista Networks embeds optics to boost 100 Gig port density

Arista Networks' latest 7500E switch is designed to improve the economics of building large-scale cloud networks.

The platform packs 30 Terabit-per-second (Tbps) of switching capacity in an 11 rack unit (RU) chassis, the same chassis as Arista's existing 7500 switch that, when launched in 2010, was described as capable of supporting several generations of switch design.   

"The CFP2 is becoming available such that by the end of this year there might be supply for board vendors to think about releasing them in 2014. That is too far off."

Martin Hull, Arista Networks

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