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Silicon Photonics

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Optical transmission beyond 100Gbps

Briefing: High-speed optical transmission. 

Part 3: What's next?

Given the 100 Gigabit-per-second (Gbps) optical transmission market is only expected to take off from 2013, addressing what comes next seems premature. Yet operators and system vendors have been discussing just this issue for at least six months.

And while it is far too early to talk of industry consensus, all agree that optical transmission is becoming increasingly complex. As Karen Liu, vice president, components and video technologies at market research firm Ovum, observed at OFC 2010, bandwidth on the fibre is no longer plentiful.


“We need to keep a very close eye that we are not creating more problems than we are solving.”

Brandon Collings, JDS Uniphase.

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Is a datacom and telecom mini-boom taking place? 

A reader commented that both semiconductor and optical transceiver lead-times are being extended and that the “good times are here”.  But what is the cause, he asked, and are good times really here?

Daryl Inniss believes it is largely a reflection of cutbacks that have run their course. “The industry cut back swiftly and deeply when the market started to tank, cutting suppliers and capacity,” says Inniss, practice leader, components at market research firm Ovum.


“I think it's recovery dynamics - people ordering a tiny bit more and there are no parts available such that lead-times are stretching out simulating a boom.”

Brad Smith, LightCounting

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40 and 100Gbps: Growth assured yet uncertainty remains 

Briefing: High-speed optical transmission.

Part 2: 40 and 100Gbps optical transmission

The market for 40 and 100 Gigabit-per-second optical transmission is set to grow over the next five years at a rate unmatched by any other optical networking segment.  Such growth may excite the industry but vendors have tough decisions to make as to how best to pursue the opportunity.

Market research firm Ovum forecasts that the wide area network (WAN) dense wavelength division multiplexing (DWDM) market for 40 and 100 Gigabit-per-second (Gbps) linecards will have a 79% compound annual growth rate (CAGR) till 2014.

In turn, 40 and 100Gbps transponder volumes will grow even faster, at 100% CAGR till 2015, while revenues from 40 and 100Gbps transponder sale will have a 65% CAGR during the same period.

Yet with such rude growth comes uncertainty.


“We upgraded to 40Gbps because we believe – we are certain, in fact – that across the router and backbone it [40Gbps technology] is cheaper”

Jim King, AT&T Labs.


Systems, transponder and component vendors all have to decide what next-generation modulation schemes to pursue for 40Gbps to complement the now established differential phase-shift keying (DPSK). There are also questions regarding the cost of the different modulation options, while vendors must assess what impact 100Gbps will have on the 40Gbps market and when the 100Gbps market will take off.  

“What is clear to us is how muddled the picture is,” says Matt Traverso, senior manager, technical marketing at Opnext.

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DSL: Will phantom channels become real deployments?

Alcatel-Lucent’s Bell Labs has announced it has achieved a data rate of 300 megabits-per-second (Mbps) over 400m using digital subscriber line (DSL) technology. 

Alcatel-Lucent is promoting its DSL Phantom Mode technology as a complement to fibre-to-the-x (FTTx) technology. Operators can use the technology to continue to extend services offerings to existing DSL subscribers as they roll out FTTx over the next decade or more.

But one analyst believes the technology could take years to commercialise and questions whether the announcement is not sending a wrong message to the industry by providing an alternative to fibre.


“The investment required to upgrade DSL is quite small”

Stefaan Vanhastel, Alcatel-Lucent





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OFC/NFOEC 2010: Industry reflections

Gazettabyte asked the views of several attendees at OFC/NFOEC 2010 to reflect on the show. In particular what developments or trends struck them as noteworthy, what they learnt and what gives them reason for optimism?

Here is a selection of their views.


“We heard again and again, that the internet service providers such as Google are still looking for solutions for their future bandwidth demand”

Andreas Umbach, u2t Photonics


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Ofidium to enter 100Gbps module market using OFDM

Briefing: High-speed optical transmission.

Part 1: The start-up

Ofidium is a 100 Gigabit start-up that refuses to follow the herd.

While the optical industry has chosen polarisation-multiplexing quadrature phase-shift keying (PM-QPSK) for 100 Gigabit-per-second (Gbps) transmission, the Australian start-up is developing a module based on orthogonal frequency division multiplexing (OFDM) modulation.


 "For data rates higher than 100Gbps, it [OFDM] is the only way to go"

Jonathan Lacey, CEO

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Mobile broadband: congestion is inevitable

Shown is a table listing the typical bandwidth requirements for various applications.

The table is taken from a recent report by Peter Rysavy of Rysavy Research, entitled Mobile Broadband Capacity Constraints And the Need for Optimization.

The report looks at the huge growth in mobile broadband services and the resulting congestion. The report includes a nice model showing how only a few intensive users can consume much of a cell's capacity. The report also discusses how operators must continue to add wireless capacity while being a lot smarter in the bandwidth consumed by applications.

To see a copy of the report, click here

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