by Stephen Hardy
Once upon a time, carriers built networks as fast as they could. They bought systems based on innovative technology that promised a roadmap toward hundreds of wavelengths traveling at speeds up to 40 Gbits/sec over a single fiber. Such fibers would pave magical information superhighways that would keep pace with the seemingly limitless demand for bandwidth the Internet promised to create among the happy and productive inhabitants of the blessed realm.
The market conditions prevalent at the start of this century almost demand fairytale terms to describe them; the “Information Era” seems so long ago and hard to credit. Nowadays, of course, the emphasis is not on building big networks or investing in innovative technology but on squeezing the cost out of the systems, subsystems, and components already in place.
Or is it? Giovanni Barbarossa, chief technology officer at Avanex (www.avanex.com), asserts that while price continues to remain important, carrier priorities have shifted. An interest in reduced operational expenses, coupled with the desire to spend capex wisely, has created demand for new technology. The air is not filled with pixie dust once again, but Barbarossa makes the case that technological innovation now rivals an Asian manufacturing capability when it comes to a successful product line, even for component and subsystem suppliers.
Barbarossa says that carrier requirements, which of course get passed through systems houses to the component and subsystem community, started to evolve away from pure cost reduction “maybe a couple of years ago” while observers were focused on how quickly suppliers could move their production to Asia.
“The recent emphasis is more on dollars spent per bit transmitted-or maybe another way to say it is the cost of ownership of the network is actually where the focus is. So that doesn’t necessarily mean lower-cost components,” Barbarossa comments. “From my perspective, it’s more about new components that provide the network operators lower capex and lower opex opportunities to manage their networks.”
The new generation of components addresses requirements to increase efficiency, add intelligence, and improve flexibility in carrier networks, Barbarossa says. Each of these three areas is characterized by advances in certain technology areas that can be combined to benefit a single product or several.
For example, emerging components and subsystems can improve efficiency by leveraging advanced modulation formats, lowering loss, reducing power consumption, decreasing dispersion, or supporting higher transmission speeds. Advances in material science and basic physics provide these benefits.
Barbarossa points to new, lower-loss dispersion compensation modules as an illustration. “Why is it lower loss? It’s not because we moved the manufacturing to Thailand, of course,” he explains. “The low loss comes from a better design of the fiber and from improved manufacturing of the fiber itself, which involves material science.”
The support of faster transmission rates also illustrates a pairing of changing carrier interests and technology advances to improve network efficiency. “Speed has always been an objective-but it wasn’t really an objective between 2000 and 2003/2004. Now we see again a comeback to 40G, for example, and maybe 100G even in datacom. And, again, it’s a better way to utilize the network,” Barbarossa says. The products companies such as Avanex plan to offer will result “from physics and from investment into new materials for new sources, new modulators, and even from an IC perspective, maybe in electronic dispersion compensation,” he explains.Electronics, along with software, will also play an important role in adding intelligence to networks, particularly to the components and systems carriers deploy. The added intelligence enables and improves such functions as monitoring, controlling, alerting, and managing, as well as promotes automation.
Monitoring in particular appears to be an important requirement, Barbarossa says. “I heard one customer say that if optical monitoring is cost-effective enough, then network operators would love to have an optical power monitor or even performance monitor with optical signal-to-noise ratio in every single node of the network,” he relates.
Barbarossa favors approaches that leverage tunable filters. Still, the ubiquity his customer envisioned is not yet economically feasible. “Most of the available optical performance solutions out there are really not addressing signal-to-noise ratio. And so having a low-cost, signal-to-noise-ratio monitor is very important. And there is a combination there between the actual physics of the tunable filter and the algorithms implemented at the firmware level. That’s where there’s a lot of work being done today to provide a low-cost and reliable solution for monitoring.”
Flexibility incorporates many of today’s most popular buzzwords, including reconfigurability, tunability, and pluggability. The idea is to provide easy upgrades and bandwidth on demand, among other goals-Barbarossa says that many people associate flexibility with futureproofing. Here, architecture and design become influential.
Reconfigurable optical add/drop multiplexers (ROADMs) have replaced tunable lasers as the flexibility flavor of the moment. However, as is often the case, the market demand hasn’t quite matched the hype. “The hardware has been available for quite some time, but I’m not sure that the operators really feel comfortable in managing them today,” Barbarossa offers. “[The wavelength-selective switch] is a good example, where the market is not where some startups thought it was going to be today, primarily because of software issues.”
The software issues revolve around managing the devices and the reconfigurable aspects of the network in general. The complexity inherent in reconfigurable networks also hinders carriers from using tunable lasers for more than just inventory control.
“From a hardware perspective, it’s definitely very challenging,” explains Barbarossa. “But that challenge is really small compared to the software challenge or to the management challenge to the network once you start moving wavelengths around by leveraging the tunability. I think it’s definitely going to happen, but I don’t really believe it’s something that’s going to happen in the next two years. Maybe three or four more.”
While tunability is most commonly associated with lasers, the attribute potentially benefits other devices. “Tunable dispersion compensation is definitely going to be a hot area,” Barbarossa predicts. “I think the optical solutions will start to grow in volume in deployment. And the cost will get to the point that electronics [-based approaches] will really be challenged.”
The trend toward more innovative technology naturally pleases someone who carries a title like chief technology officer. However, all companies must watch the bottom line. Fortunately, the new generation of components and subsystems naturally lends itself to higher margins-an advantage suppliers intend to seize. “Selling at loss is not really a healthy thing anymore,” Barbarossa concludes. “I think most of the companies, including the startups, are being a little more careful about what they really put on the market.”Stephen Hardy is the editorial director and associate publisher of Lightwave.