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ECOC: Consulting the crystal ball

Trying to predict the future is a good way to invite egg on face, as many people throughout the ages have discovered. But yet that’s exactly what plenary speakers are expected to do when they take to the stage, and at the European Conference on Optical Communications (ECOC) in Brussels today it was the turn of Rod Alferness, chief scientist at Bell Labs.

Alferness had been asked to talk on the same topic at ECOC in Madrid 10 years ago, and before looking forward to the next 10 years, he took the opportunity to look back to see how his predictions had turned out.

Back then 1 Tbit/s had already been demonstrated, so transmission was essentially a solved problem. The real issue for the optical networking industry at the time was how to “manage and tame” all this bandwidth. Mesh and reconfigurable networks based on ROADMs looked like the optimum solution, and in fact that has turned out to be the case, even if it has taken a little longer to arrive than expected (no rotten tomatoes so far).

But going forward, increasing transmission capacity will not be so easy. The belief that fibre has unlimited bandwidth has been overturned. “I think that in the next 10 years we are going to be very challenged to find the bandwidth that society demands of us in a cost-effective way,” Alferness said.

The fundamental drivers for bandwidth growth aren’t going away, the opposite in fact, as new applications like high-definition TV, video on demand, and 3D video-conferencing could stimulate demand in an unprecedented way, particularly if the bottleneck in the access network is tackled.

While there are differences of opinion on how much bandwidth will grow, even the most conservative estimates suggest that some significant advances in network technology will be required. Alferness presented a chart showing how the capacity demonstrated by “hero experiments” is increasing far more slowly than before. “In the past we would have said a breakthrough was required,” he observed.

Although it’s impossible to predict what that breakthrough could be, advanced modulation formats, which make more efficient use of fibre spectrum, are definitely part of the picture, and so is photonic integration. “It is absolutely clear in my mind that substantial integration is going to be critical [to high-capacity transmission],” he said.

Ultimately Alferness believes that optical components will be integrated with electronics. “I think 10 years ago we thought optics had all the answers, now I think optics and electronics are going to have to work together,” Alferness proposed.

The marriage of optics and electronics could take place in either indium phosphide materials and silicon photonics, which could turn out to be very interesting technology race. However, the horizontal nature of the business model will complicate the investment case for new components technologies, he warns.

The next 10 years

Here’s Alferness’ take on other trends for the industry over the next 10 years:

• On the overall network: It will be one network. Increasingly the data layer and the optical layer are converging. If we have intelligent routers at the edge of the network, the efficiency of that network is going to be improved.
• On green issues: Energy and carbon footprint will be critically important as we design new optical systems, and it will influence the decisions that are made on technology, particularly decisions about architecture.

• On WDM-PON: WDM-PON will happen at least to enterprises if not to homes.
• On wireless: Wireless needs an interconnection network, which is provided by optical. Fibre networks that go out to homes will also go out to wireless base stations to provide backhaul.
• On multiple antennas: Base stations should talk to each other. 3–5 base stations could provide communications to a single user, by strengthening the signal instead of interfering with one another. But they can only do that if there is an ubiquitous low-cost interconnect between base stations, and that’s optical, obviously.

• On network storage: Increasingly we will put storage in the network, closer to the end user to reduce transmission requirements. But its’ a wild card: more storage in the network means more content will available to users, which will help to drive traffic.
• On telepresence: We need to offer people the opportunity to really get together without travelling, whether that’s telepresence or something else. We have flattened the world, and built a global community, and people will be looking for more personal ways to communicate.

• On in-home networks: We will see wireless networks based on femtocell base stations. Initially the broadband connection in your home will backhaul the traffic, in future, femtocells may also serve traffic coming down your road.

• On quantum computing: Is it the Google of the next decade? Quantum computing enables massively parallel operations. It could perform searches several orders of magnitude faster than today’s searches, and in 10 years we’re going to need something that does searches that much faster.

Posted by Pauline Rigby on September 22, 2008 8:54 PM | Permalink