Light Reading

Intel Detects More Silicon Photonics

Craig Matsumoto
News Analysis
Craig Matsumoto
12/7/2008
50%
50%

It's been almost two years since Intel Corp. (Nasdaq: INTC) announced any "breakthroughs" in silicon photonics. Well, we can't let that stand, can we?

Fear not. Intel is publishing its latest results today in the journal Nature Photonics, describing an Avalanche Photodiode (APD) -- a type of detector for the receiving end of an optical link -- that's made of silicon (but not completely -- there's also a germanium layer).

Intel's silicon photonics efforts so far have focused on modulators and lasers. (See Intel at 40, Intel Pushes Silicon Modulator , Intel Fires Up Silicon Laser, Intel Claims Laser Breakthrough, Intel Gets Passive on Optics, and Intel's Modest Modulator .)

The APD is new ground, not just because it's a different part, but because its performance outdoes "any equivalent device in a III-V-based or exotic material," says Mario Paniccia, an Intel fellow and director of the company's Photonics Technology Lab. (III-V, or "three-five," refers to a class of compounds such as indium phosphide (InP) or gallium arsenide.)

That's a first. Silicon photonics have always been a tradeoff. The devices would be easier to integrate and cheaper to manufacture, since they can be built using complementary metal-oxide semiconductor (CMOS) techniques that are commonplace in the chip world -- but the performance suffers. Intel has been aiming for CMOS devices with 90 percent of the performance of InP ones.

The APDs aren't anywhere close to being a marketable product, by the way. "This is a research result. It's actually a very new result, Paniccia says.

Like any big company, Intel has started and ended its share of projects. (See Will Intel Trash Telecom?, Marvell Takes a Bit of Intel, Intel Dumps Dialogic, and Intel Hands Off to Cortina.) But silicon photonics has stuck, a testament to how vital Intel believes this technology is to the future of computing.

There have been changes, though. All the photonics work is now being done at Numonyx BV , a spinoff created early this year out of the Intel and STMicroelectronics NV (NYSE: STM) flash memory businesses.

Why? It so happens, Intel's silicon photonics work was being done at what is now Numonyx's fab. Intel found it easiest to just keep the operation in place, Paniccia says. So, the engineers technically work at Numonyx and build their devices on the same Numonyx production lines that are churning out high-volume memory chips.

Meanwhile, silicon photonics are reaching the commercial stage, mainly in the form of active optical cables for data centers. Kotura Inc. , Lightwire Inc. , and Luxtera Inc. are among the companies producing or pursuing commercial products. (See Silicon Photonics Advance PIC Possibilities, Luxtera Goes Commercial, and Lightwire Debuts Its Silicon Photonics.)

Going the distance
Intel's silicon photonics efforts are aimed mostly at short-reach connections, but the APD could easily be applied to a telecom network. The devices usually get mentioned in the context of long-haul spans, partly because they're too expensive to use elsewhere -- $200 to $300 apiece, Paniccia says.

The advantage of an APD is that a weaker light source can generate a sufficient current. That means you can take some liberties on the transmission side -- moving the source a farther distance away, for instance. Among the possible applications Paniccia cited was the fiber-to-the-home network, where APDs could conceivably be used to extend the reach of fiber links.

Performance for APDs can be measured in the gain-bandwidth product -- that is, the device's gain multiplied by the speed of the connection, which comes out to a fixed number measured in Hertz. (Note that this means the gain goes down as the bandwidth gets faster.)

For an indium phosphide APD, that gain-bandwidth product is around 120 GHz, Intel says. Intel's silicon APD is showing 340 GHz, implying that it would have better gain than InP devices.

Intel didn't specify the speed it's aiming for with APD, but the company is shooting high with its marketing, saying a silicon APD could be an aid in 40-Gbit/s networks. That would be quite a leap, as APDs are only available in speeds up to 2.5 Gbit/s today.

"A 40-Gbit/s APD might be really pushing it, but as something they're talking about for the future, it might be reasonable," says Ali Abouzari, vice president of sales for CyOptics Inc.

To describe which part of the APD is made of silicon, it's helpful to look at how an APD works. A normal photodiode receives a photon of light and produces an electron/hole pair (you can think of a "hole" as the opposite of an electron), creating electrical current. An APD adds a multiplication region where that reaction gets amplified, creating many more electron/hole pairs and a stronger current.

Intel used silicon for the multiplication region. But to absorb the photon and get the process started, Intel needed germanium, because silicon is transparent to the infrared wavelengths used in communications. Silicon can't "catch" the light.

Plenty of challenges exist with this approach. One is that the silicon and germanium atoms form lattices that don't quite match up, and that can cause some current to leak out even when there's no light present. Intel is still working on getting that "dark current" down, Paniccia says.

— Craig Matsumoto, West Coast Editor, Light Reading

(8)  | 
Comment  | 
Print  | 
Newest First  |  Oldest First  |  Threaded View        ADD A COMMENT
nodak
50%
50%
nodak,
User Rank: Light Beer
12/5/2012 | 3:25:43 PM
re: Intel Detects More Silicon Photonics
"That would be quite a leap, as APDs are only available in speeds up to 2.5 Gbit/s today. "

I think you might want to review this statement. Just a quick search turns up APDs being used in 10G receivers in 1996 experiments and in 2001 products (not an exhaustive search, probably things that could turn up earlier). Were you perhaps talking about the use of PIN diodes?
Pete Baldwin
50%
50%
Pete Baldwin,
User Rank: Light Beer
12/5/2012 | 3:25:43 PM
re: Intel Detects More Silicon Photonics
Luxtera already has silicon APDs that I think it's shown publicly. It's at least talked about them publicly, in papers at OFC/NFOEC, ECOC, and other shows.

It's the same concept Intel is using -- an absorption layer made of Ge and a multiplication layer of Si -- but Luxtera says its model is a waveguide-based photodetector.

Intel, by contrast, hasn't gotten its APD to work in waveguide form yet; on the conference call, the company says it's still working on such a thing.
litsem
50%
50%
litsem,
User Rank: Light Beer
12/5/2012 | 3:25:42 PM
re: Intel Detects More Silicon Photonics
I may be wrong but I believe Germanium APDs in Silicon have been done in lab and even commercialized by companies like Luxtera long before this article. I understand it's a first for Intel and maybe they are better in some ways, but I don't believe that it is an industry first.
Pete Baldwin
50%
50%
Pete Baldwin,
User Rank: Light Beer
12/5/2012 | 3:25:41 PM
re: Intel Detects More Silicon Photonics
litsem -- You're mostly right; Luxtera's got silicon APDs in the lab. They tell me they haven't commercialized them yet. (See the first comment in the thread.)

The "first" that Intel is touting is the performance that exceeds that of silicon.

Luxtera, though, says they get performance that's better than Intel's -- although that's by a different metric, in terms of sensitivity (1dB better than Intel, they claim.)

Not sure Luxtera's in any rush to commericalize the silicon APD. They're really focused on short reach connections right now, and the APD just isn't that useful to them there.
Pete Baldwin
50%
50%
Pete Baldwin,
User Rank: Light Beer
12/5/2012 | 3:25:41 PM
re: Intel Detects More Silicon Photonics
You may be right; it looks like Eudyna's got one. My mistake.

I was talking more about commercially, currently available devices, but yeah, there have been papers about 10G APDs and probably some startup work in the early '00s that's dead.
bw
50%
50%
bw,
User Rank: Light Beer
12/5/2012 | 3:25:40 PM
re: Intel Detects More Silicon Photonics
Craig: anybody in the industry should know that 10G APDs had been in commercial use since late 1990s supplied by Agere (now CyOpitcs), Fujitsu (Eudyna), JDSU, etc. Just check every 80km 10G 300pin transponders: each has a 10G APD.
Pete Baldwin
50%
50%
Pete Baldwin,
User Rank: Light Beer
12/5/2012 | 3:25:31 PM
re: Intel Detects More Silicon Photonics
bw - thanks for the info.

Folks I'd talked to couldn't point to any 10G APDs, so obviously I needed to check around more (or maybe I misunderstood something.)
^Eagle^
50%
50%
^Eagle^,
User Rank: Light Beer
12/5/2012 | 3:25:29 PM
re: Intel Detects More Silicon Photonics
Craig,

indeed, apd's at 10G have been around for quite sometime. Also there are APD's at 40G as well.

only thing new here is doing it in silicon (quasi silicon). What they don't tell you is that you actually cannot take advantage of a standard CMOS line and integrate silicon (active) photonics so easily as the Germanium they use to get the APD working is not used on standard CMOS line in this way. LOTS of additional tooling designs, fabrication design work and fundamentals need to be solved to make it work, and those special things are not currently used on CMOS lines. So, HUUUGE investment is still required to retool. Therefore, one wonders if indeed this will be a lower cost approach (silicon photonics.. CMOS but not really...) over traditional GaS and InP active photonics considering the EPI cost for most FABs currently in the world have been written off already due to the last 3 "downturns". Perhaps in the long term CMOS photonics will fly, but for now, the advantages are purely theoretical. Long way from changing the world. Look for lower cost InP approaches and hybrid approaches to dominate for quite awhile I think.

sailboat
From The Founder
Against the odds, Huawei is growing its telecoms networking equipment business in the US -- that should be ringing some alarm bells for domestic vendors.
Flash Poll
Live Streaming Video
CLOUD / MANAGED SERVICES: Prepping Ethernet for the Cloud
Moderator: Ray LeMaistre Panelists: Jeremy Bye, Leonard Sheahan
Between the CEOs
CEO Chat With Jeff Miller, ActiveVideo

8|28|15   |   19:05   |   (0) comments


Jeff Miller, President and CEO of ActiveVideo, talks to Light Reading founder and CEO Steve Saunders about the impact of virtualization on the TV and video distribution market.
LRTV Huawei Video Resource Center
Vodafone: Mobile Money Is About Customer Trust

8|27|15   |   06.36   |   (0) comments


Light Reading spoke with Vodafone's Ian Ravenscroft about the unique responsibilities and opportunities facing operators handling customers' financial transactions over the network.
Telecom Innovators Video Showcase
Palo Alto Networks on Expanding in the Carrier/Service Provider Market

8|26|15   |   07:54   |   (0) comments


Alfred Lee from Palo Alto Networks tells Steve Saunders about their new chassis-based system, the PA-7080, and how it can benefit service providers compared to legacy firewalls.
LRTV Custom TV
Global Services Forum Preview

8|25|15   |   02:36   |   (0) comments


Light Reading's CEO and Founder Steve Saunders talks about Huawei's upcoming Global Services Forum with the help of Heavy Reading's Patrick Donegan and Teresa Mastrangelo.
Telecom Innovators Video Showcase
Infoblox on DNS Threat Index

8|19|15   |   04:39   |   (0) comments


Dilip Pillaipakam from Infoblox talks to Steve Saunders about his company's core network services.
Between the CEOs
CEO Chat With Ihab Tarazi, Equinix

8|14|15   |   20:18   |   (1) comment


Equinix CTO Ihab Tarazi talks to Light Reading founder and CEO Steve Saunders about the dramatic changes in the data center, cloud and interconnect markets and discusses the impact of SDN and NFV in the coming years.
Telecom Innovators Video Showcase
The Netformx Ecosystem

8|14|15   |   09:39   |   (1) comment


Ittai Bareket, CEO of Netformx, talks with Steve Saunders about the Netformx Ecosystem, which employs cutting-edge prescriptive analytics to help solution providers maximize profits.
Telecom Innovators Video Showcase
Versa Networks on Leveraging VNFs

8|12|15   |   07:37   |   (0) comments


Kumar Mehta, founder and CEO of stealth mode startup Versa Networks, talks with Steve Saunders about how providers can best leverage virtualized network functions (VNFs).
LRTV Custom TV
Transforming the Network Through OPNFV

8|5|15   |   7:09   |   (0) comments


Sandra Rivera, VP Data Center Group; GM Network Platforms Group, Intel Corporation, on OPNFV Arno and how the industry is coming together to accelerate the deployment of NFV and transform the network.
LRTV Huawei Video Resource Center
Huawei ONS Product Demo

8|3|15   |   6:01   |   (0) comments


Huawei shows at Open Networking Summit 2015 in Santa Clara how its SDN and NFV solutions embrace openness.
LRTV Custom TV
End-User or Enterprise Benefits to the New IP

7|30|15   |   04:27   |   (1) comment


Andrew Coward discusses what the New IP means to end users or enterprise customers. He explains compelling reasons, including how every customer can get their own network, from the transformation to the New IP.
LRTV Custom TV
Network Visibility & the New IP

7|30|15   |   02:23   |   (0) comments


Mukund Srigopal provides an explanation of what network visibility is and how it is essential as service providers transition to the New IP. In addition, the importance of the network packet broker is discussed.
Upcoming Live Events
September 16-17, 2015, The Westin Galleria Dallas, Dallas, TX
September 16, 2015, The Westin Galleria Dallas, Dallas, TX
September 16, 2015, The Westin Galleria Dallas, Dallas, TX
September 29-30, 2015, The Westin Grand Müchen, Munich, Germany
October 14-15, 2015, New Orleans Ernest N. Morial Convention Center, New Orleans, LA
November 5, 2015, Hilton Santa Clara, Santa Clara, CA
November 17, 2015, Santa Clara, California
December 1, 2015, The Westin Times Square, New York City
December 2, 2015, The Westin Times Square, New York City
All Upcoming Live Events
Infographics
Cisco's cloud and virtualization portfolio can increase business agility and innovation by building a more flexible network architecture.
Hot Topics
T-Mobile CEO Plays Data Traffic Cop
Sarah Thomas, Editorial Operations Director, 8/31/2015
Verizon Hums a Driving Tune
Sarah Thomas, Editorial Operations Director, 8/26/2015
Sprint's Claure: '3 to 5 Years' to Turnaround
Dan Jones, Mobile Editor, 8/25/2015
Time to Monetize Cable WiFi
Alan Breznick, Cable/Video Practice Leader, 8/31/2015
Like Us on Facebook
Twitter Feed
September 22, 2015
Media Begins With “Me”
Webinar Archive
BETWEEN THE CEOs - Executive Interviews
The scene: Last Saturday, lunchtime, the interior of a shi-shi-foo-foo eatery in Manhattan's SoHo district.
Jeff Miller, President and CEO of ActiveVideo, talks to Light Reading founder and CEO Steve Saunders about the impact of virtualization on the TV and video distribution market.
Cats with Phones
Cats Are a Smartphone's Best Friend Click Here
Whoever said cats didn't live to please their humans?