Monolithic silicon photonic chips move a step closer

Indium phosphide laser arrays have been grown on a 300 mm silicon wafer by Ghent University and imec, the Belgium nano-electronics R&D centre. Growing indium phosphide lasers directly onto the silicon wafer promises compact monolithic silicon photonics circuits.   

Shown are three v-shaped indium phosphide lasers and their gratings on a silicon-on-insulator substrate. Source: Ghent University, imec

Silicon photonics chips are hybrid designs because of silicon’s inability to generate light. Silicon photonics companies either couple a discrete laser to a chip or bond indium phosphide wafers or ‘chiplets' to the silicon wafer and process it to create working lasers that become part of the silicon photonics chip. Growing lasers directly on silicon creates a third approach for the densest applications.

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ECOC 2015 Review - Final Part

The second and final part of the survey of developments at the ECOC 2015 show held recently in Valencia.  

Part 2 - Client-side component and module developments   

• The first SWDM Alliance module shown
• More companies detail CWDM4, CLR4 and PSM4 mid-reach modules
• 400 Gig datacom technologies showcased
• The CFP8 MSA for 400 Gigabit Ethernet unveiled

The CFP MSA modules including the newest CFP8. Source: Finisar

• Lumentum and Kaiam use silicon photonics for mid-reach modules
• Finisar demonstrates a 10 km 25 Gig SFP28, and low-latency 25 Gig and 100 Gig SR4 interfaces 

Shortwave wavelength-division multiplexing

Finisar demonstrated the first 100 gigabit shortwave wavelength-division multiplexing (SWDM) module at ECOC. Dubbed the SWDM4, the 100 gigabit interface supports WDM over multi-mode fibre. Finisar showed a 40 version at OFC earlier this year. “This product [the SWDM4] provides the next step in that upgrade path,” says Rafik Ward, vice president of marketing at Finisar. 

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ECOC '15 Reflections: Part 2

Part 2: More industry executives share the trends and highlights they noted at the recent European Conference on Optical Communication (ECOC) event, held in Valencia. 

Martin Zirngibl, head of network enabling components and technologies at Bell Labs. 

Silicon Photonics is seeming to gain traction, but traditional component suppliers are still betting on indium phosphide.

There are many new start-ups in silicon photonics, most seem to be going after the 100 gigabit QSFP28 market. However, silicon photonics still needs a ubiquitous high-volume application for the foundry model to be sustainable.

There is a battle between 4x25 Gig CWDM and 100 Gig PAM-4 56 gigabaud, with most people believing that 400 Gig PAM-4 or discrete multi-tone with 100 Gig per lambda will win.

Will coherent make it into black and white applications - up to 80 km - or is there a role for a low-cost wavelength-division multiplexing (WDM) system with direct detection?

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ECOC 2015: Reflections

Gazettabyte asked industry executives what trends and highlights they noted at the recent European Conference on Optical Communication (ECOC) event, held in Valencia. Here are three views.

Valery Tolstikhin, head of a design consultancy, Intengent

ECOC was a big show and included a number of satellite events, such as the 6^th European Forum on Photonic Integration, the 3^rd Optical Interconnect in Data Center Symposium and Market Focus, all of which I attended. So, lots of information to digest. 

My focus was mainly on data centre optical interconnects and photonic integration.

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Rockley demos a silicon photonics switch prototype

Part 1: Rockley Photonics

Rockley Photonics has made a prototype switch to help grow the number of servers that can be linked in a data centre. The issue with interconnection networks inside a data centre is that they do not scale linearly as more servers are added.  

Dr. Andrew Rickman

“If you double the number of servers connected in a mega data centre, you don’t just double the complexity of the network, it goes up exponentially,” explains Andrew Rickman, co-founder, chairman and CEO at Rockley Photonics. “That is the problem we are addressing.”

By 2017 and 2018, it will still be possible to build the networks that large-scale data centre network operators require, says Rickman, but at an ever increasing cost and with a growing power consumption. “The basic principles of what they are doing needs to be rethought,” he says.

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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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