Compute vendors set to drive optical I/O innovation

Part 2: Data centre and high-performance computing trends

Professor Vladimir Stojanovic has an engaging mix of roles.

When he is not a professor of electrical engineering and computer science at the University of California, Berkeley, he is the chief architect at optical interconnect start-up, Ayar Labs.

Professor Vladimir Stojanovic

Until recently Stojanovic spent four days each week at Ayar Labs. But last year, more of his week was spent at Berkeley.

Stojanovic is a co-author of a 2015 Nature paper that detailed a monolithic electronic-photonics technology. The paper described a technological first: how a RISC-V processor communicated with the outside world using optical rather than electronic interfaces. 

It is this technology that led to the founding of Ayar Labs.

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COBO targets year-end to complete specification

Part 3: 400-gigabit on-board optics

• COBO will support 400-gigabit and 800-gigabit interfaces 
• Three classes of module have been defined, the largest supporting at least 17.5W 

The Consortium for On-board Optics (COBO) is scheduled to complete its module specification this year.

A draft specification defining the mechanical aspects of the embedded optics - the dimensions, connector and electrical interface - is already being reviewed by the consortium’s members.

Brad Booth“The draft specification encompasses what we will do inside the data centre and what will work for the coherent market,” says Brad Booth, chair of COBO and principal network architect for Microsoft’s Azure Infrastructure.

COBO was established in 2015 to create an embedded optics multi-source agreement (MSA). On-board optics have long been available but until now these have been proprietary solutions. 

“Our goal [with COBO] was to get past that proprietary aspect,” says Booth. “That is its true value - it can be used for optical backplane or for optical interconnect and now designers will have a standard to build to.” 

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Meeting the many needs of data centre interconnect

High capacity. Density. Power efficiency. Client-side optical interface choices. Coherent transmission. Direct detection. Open line system. Just some of the requirements vendors must offer to compete in the data centre interconnect market.

“A key lesson learned from all our interactions over the years is that there is no one-size-fits-all solution,” says Jörg-Peter Elbers, senior vice president of advanced technology, standards and IPR at ADVA Optical Networking. “What is important is that you have a portfolio to give customers what they need.”

 Jörg-Peter Elbers

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The OIF’s 400ZR coherent interface starts to take shape

Part 2: Coherent developments

The Optical Internetworking Forum’s (OIF) group tasked with developing two styles of 400-gigabit coherent interface is now concentrating its efforts on one of the two.

When first announced last November, the 400ZR project planned to define a dense wavelength-division multiplexing (DWDM) 400-gigabit interface and a single wavelength one. Now the work is concentrating on the DWDM interface, with the single-channel interface deemed secondary. 

Karl Gass"It [the single channel] appears to be a very small percentage of what the fielded units would be,” says Karl Gass of Qorvo and the OIF Physical and Link Layer working group vice chair, optical, the group responsible for the 400ZR work.

The likelihood is that the resulting optical module will serve both applications. “Realistically, probably both [interfaces] will use a tunable laser because the goal is to have the same hardware,” says Gass.   

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Talking markets: Oclaro on 100 gigabits and beyond

Oclaro’s chief commercial officer, Adam Carter, discusses the 100-gigabit market, optical module trends, silicon photonics, and why this is a good time to be an optical component maker.

Oclaro has started its first quarter 2017 fiscal results as it ended fiscal year 2016 with another record quarter. The company reported revenues of $136 million in the quarter ending in September, 8 percent sequential growth and the company's fifth consecutive quarter of 7 percent or greater revenue growth.

Adam CarterA large part of Oclaro’s growth was due to strong demand for 100 gigabits across the company’s optical module and component portfolio.

The company has been supplying 100-gigabit client-side optics using the CFP, CFP2 and CFP4 pluggable form factors for a while. “What we saw in June was the first real production ramp of our CFP2-ACO [coherent] module,” says Adam Carter, chief commercial officer at Oclaro. “We have transferred all that manufacturing over to Asia now.”

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Ranovus shows 200 gigabit direct detection at ECOC

Ranovus has announced it first direct-detection optical products for applications including data centre interconnect.

Saeid AramidehThe start-up has announced two products to coincide with this week’s ECOC show being held in Dusseldorf, Germany.

One product is a 200 gigabit-per-second (Gbps) dense wavelength-division multiplexing (WDM) CFP2 pluggable optical module that spans distances up to 130km. Ranovus will also sell the 200Gbps transmitter and receiver optical engines that can be integrated by vendors onto a host line card. 

The dense WDM direct-detection solution from Ranovus is being positioned as a cheaper, lower-power alternative to coherent optics used for high-capacity metro and long-haul optical transport. Using such technology, service providers can link their data centre buildings distributed across a metro area. 

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QSFP28 MicroMux expands 10 & 40 Gig faceplate capacity

• ADVA Optical Networking's MicroMux aggregates lower rate 10 and 40 gigabit client signals in a pluggable QSFP28 module
• ADVA is also claiming an industry first in implementing the Open Optical Line System concept that is backed by Microsoft 

The need for terabits of capacity to link Internet content providers’ mega-scale data centres has given rise to a new class of optical transport platform, known as data centre interconnect.

Source: ADVA Optical Networking

Such platforms are designed to be power efficient, compact and support a variety of client-side signal rates spanning 10, 40 and 100 gigabit. But this poses a challenge for design engineers as the front panel of such platforms can only fit so many lower-rate client-side signals. This can lead to the aggregate data fed to the platform falling short of its full line-side transport capability.

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