Data centres to give silicon photonics its chance

Part 4: A large data centre operator’s perspective

The scale of modern data centres and the volumes of transceivers they will use are going to have a significant impact on the optical industry. So claims Facebook, the social networking company.

Katharine Schmidtke

Facebook has been vocal in outlining the optical requirements it needs for its large data centres.

The company will use duplex single-mode fibre and has chosen the 2 km mid-reach 100 gigabit CWDM4 interface to connect its equipment.

But the company remains open regarding the photonics used inside transceivers. “Facebook is agnostic to technology,“ says Katharine Schmidtke, strategic sourcing manager, optical technology at Facebook. “There are multiple technologies that meet our requirements.” 

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Verizon tips silicon photonics as a key systems enabler

Verizon's director of optical transport network architecture and design, Glenn Wellbrock, shares the operator’s thoughts regarding silicon photonics.

Part 3: An operator view

Glenn Wellbrock is upbeat about silicon photonics’ prospects. Challenges remain, he says, but the industry is making progress. “Fundamentally, we believe silicon photonics is a real enabler,” he says. “It is the only way to get to the densities that we want.”

Glenn Wellbrock

Wellbrock adds that indium phosphide-based photonic integrated circuits (PICs) can also achieve such densities.

But there are many potential silicon photonics suppliers because of its relatively low barrier to entry, unlike indium phosphide. "To date, Infinera has been the only real [indium phosphide] PIC company and they build only for their own platform,” says Wellbrock.

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The quiet period of silicon photonics

Michael Hochberg discusses his book on silicon photonics and the status of the technology. Hochberg is director of R&D at Coriant's Advanced Technology Group. Previously he has been an Associate Professor at the University of Delaware and at the National University of Singapore. He was also a director at the Optoelectronic Systems Integration in Silicon (OpSIS) foundry, and was a co-founder of silicon photonics start-up, Luxtera.

Part 2: An R&D perspective

If you are going to write a book on silicon photonics, you might as well make it different. That is the goal of Michael Hochberg and co-author Lukas Chrostowski, who have published a book on the topic.

Michael HochbergHochberg says there is no shortage of excellent theoretical textbooks and titles that survey the latest silicon photonics research. Instead, the authors set themselves the goal of creating a design manual to help spur a new generation of designers.

The book aims to provide designers with all the necessary tools and know-how to develop silicon photonics circuits without needing to be specialists in optics.

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Silicon photonics: "The excitement has gone"

The opinion of industry analysts regarding silicon photonics is mixed at best. More silicon photonics products are shipping but challenges remain.

Part 1: An analyst perspective

"The excitement has gone,” says Vladimir Kozlov, CEO of LightCounting Market Research. “Now it is the long hard work to deliver products.” 

Dale Murray, LightCounting

However, he is less concerned about recent setbacks and slippages for companies such as Intel that are developing silicon photonics products. This is to be expected, he says, as happens with all emerging technologies.

Mark Lutkowitz, principal at consultancy fibeReality, is more circumspect. “As a general rule, the more that reality sets in, the less impressive silicon photonics gets to be,” he says. “The physics is just hard; light is not naturally inclined to work on the silicon the way electronics does.”

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Europe gets its first TWDM-PON field trial

Vodafone is conducting what is claimed to be the first European field trial of a multi-wavelength passive optical networking system using access equipment from Alcatel-Lucent. 

Source: Alcatel-Lucent

The time- and wavelength-division multiplexed passive optical network (TWDM-PON) technology being used is a next-generation access scheme that follows on from 10 gigabit GPON (XG-PON1) and 10 gigabit EPON. 

“There appears to be much more 'real' interest in TWDM-PON than in 10G GPON,” says Julie Kunstler, principal analyst, components at Ovum. 

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Silicon photonics economics set to benefit III-V photonics

Silicon photonics promises to deliver cheaper optical components using equipment, processes and fabrication plants paid for by the chip industry. Now, it turns out, traditional optical component players using indium phosphide and gallium arsenide can benefit from similar economies, thanks to the wireless IC chip industry.

Valery TolstikhinSilicon photonics did a good thing; it turned the interest of the photonics industry to the operational ways of silicon 

So argues Valery Tolstikhin, head of a design consultancy and former founder and CTO of Canadian start-up OneChip Photonics. The expectations for silicon photonics may still to be fulfilled, says Tolstikhin, but what the technology has done is spark interest in the economics of component making. And when it comes to chip economics, volumes count.

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IBM demos a 100 Gigabit silicon photonics transceiver

IBM has demonstrated a 100 gigabit transceiver using silicon photonics technology, its most complex design unveiled to date. The 100 gigabit design is not a product but a technology demonstrator, and IBM says it will not offer branded transceivers to the marketplace.

“It is a demonstration vehicle illustrating the complex design capabilities of the technology and the functionality of the optical and electrical components,” says Will Green, manager of IBM’s silicon integrated nano-photonics group. 

Will Green

IBM has been developing silicon photonics technology for over a decade, starting with building-block optical functions based on silicon, to its current monolithic system-on-chip technology that includes design tools, testing and packaging technologies.

Now this technology is nearing commercialisation. 

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