Design software breaks through language barriers

April 1, 2001


Long a staple of the electronics industry, design software is now an invaluable player in the photonics industry. Component and network development that once took days, weeks, or months using primitive, hand-operated solutions or spreadsheets can now be done in a matter of hours and minutes. Design software enables users to answer complex questions they could not otherwise answer-at least not without building components and whole networks just for testing purposes, which is prohibitively expensive and, as Alain Cohen, president and chief technology officer of OPNET Technologies Inc. (Washington, DC) asserts, "not very portable. You can't take it around in your briefcase to show it to a customer."

Photonic design software falls into two basic categories: one enables users to design and simulate the actual components themselves, while the other facilitates the design, simulation, and optimization of systems around those components, or models the behavior of those systems in a network. At both levels, however, design software is emerging as the de facto language of communication between engineers, equipment vendors, network planners, service providers, salespeople, and customers themselves.

"It's like Microsoft Word," explains Arthur Lowery, group technology officer for optical systems at VPI Virtual Photonics (Holmdel, NJ). "People send other people Word document attachments now as the de facto language of communication. The same is happening in the photonics industry. People are sending each other virtual photonic simulation files in order to evaluate concepts."

"The benefit of having a common language for the exchange of ideas is especially apparent in this deregulated context where there are so many different suppliers, so many different ideas, so many networks," agrees Elizabeth Parsons Morgan, group vice president of marketing and communications at VPI. "There is tremendous benefit in having a de facto platform for the exchange of ideas and dialogs to speed time-to-market."

Design software is also a language that is easily understood. From a human resource management perspective, its benefits are numerous. "You can use the technology or the software to embed expert rules into the design environment so that a new workforce can take the design tool as a framework for their work," explains Morgan. "It means you don't have to be an expert in simulation to design systems."

Gail Lalk, director in the optical-network department at Telcordia Technologies Inc. (Piscataway, NJ), cites design software's clear cost-cutting benefits, as well. "What design software can do is it can, in fact, replace to some extent the need for high-tech talent," which helps vendors reduce overhead, she says.

At the component device level, technologies that were unheard of six months ago are up and running today in labs, claims P. HarshaVardhana, group technical officer for transport Internet Protocol optical networking at VPI. "So how do you move it from the lab to the network in a cost-effective way-that is the design issue," he says. Design software addresses four fundamental questions: what functionality, in which box, where in the network, and at what cost?

Design software at this level is used to design the physical device; the user inputs the geometry and materials, and the software aids in the functional design and simulates the performance. RSoft Inc. (Ossining, NY), for example, offers BeamPROP, a design and simulation tool for WDM devices, switches, modulators, multimode interference devices, passive 1xN or NxN splitters, standard- and specialty-fiber design, long-period fiber gratings, and sensor structures.

Using an arrayed waveguide grating (AWG) as an example, Robert Scarmozzino, RSoft founder and chief scientist/developer, explains that "BeamPROP allows you to draw the optical circuit. It's equivalent to IC design. When you design something like the Intel chip, all the transistors and stuff are placed on a schematic representation of the chip, which is then used to both fabricate the chip and simulate the chip. The same kind of thing happens here. You draw the representation of your circuit, in this case an AWG, and then you use BeamProp to draw that and then simulate the performance of it. When you are happy with the performance, you use BeamProp to generate a mask, and then you use the mask to produce the chip."

While most vendors have some sort of internal, proprietary software they use to model their own equipment, Telcordia's Lalk warns that those internal programs may no longer be enough to meet the needs of the market. "There are about 6,000 worldwide optical-network component suppliers, and all of that got built up with this huge economic upturn in the last few years," she explains. "Now, we are starting to move into an economic downturn, and what's probably going to happen with all of those companies is that there will be significant consolidation."

The players who have the tools to help them predict not just what their own tools will do, but what their competitors' tools will do and how their own tools will work in other vendors' systems will be most successful. They will be able to reduce their design-cycle times, reduce costs, and improve the efficiency of their operations.

In one area, component design software has not yet reached the same level of maturity as its counterpart in the electronics arena. When asked if users can input a specific product number from a specific vendor, say, a Corning optical amplifier, Scarmozzino admits, "That is not yet the industry norm, to be able to select part numbers and then include them in a system simulation. That's the norm in the electronics industry, but the norm right now is more generic models of the type of component for which the user would supply data relevant to their specific component."

Understanding the behavior of individual components is the goal of component design software, but network design software must calculate the behavior of hundreds of such components on the system level. Network design tools frequently offer both simulation and optimization, which provide slightly different functions, says Cohen. A simulation models the behavior of the network and is used to determine such functions as restoration timing. It tells the user, "Here is what's going to happen." Optimization, on the other hand, searches for a better network design.

Network design software must have an understanding of how the network actually behaves and how components and systems in that network behave. It must also be flexible to keep pace with the networking industry.

There are hard-wired solutions currently available, but they can only solve problems in a particular way. Given the rapid technological changes in the space, a hard-wired solution that was perfectly viable one day may be invalidated the next. "That sort of approach to solving a problem in an abstract way is fine for the academic environment," says Cohen, "but a vendor or service provider who wants to use that has to kind of force-fit or shoe-horn their actual network design or equipment design into an abstract or academic model."

OPNET Technologies offers solutions at the system engineering level to address both strategic and tactical issues. Its OPNET Modeler, for example, allows users to design and study networks, protocols, and applications, with the aim of boosting R&D productivity and reducing time-to-market.

"An example might be, okay, if we can reengineer our systems so that the maximum transmission distance without having to regenerate is now higher, what does that do for a network?" asks Cohen. "Obviously, you would expect it to reduce costs, but by how much? People want to know what is the return on investment of doing something like that. Maybe those new systems cost more to install, but the question is, what will it save you in terms of your overall network design? Those are the answers that you can get from our solutions, because we'll actually simulate the behavior of the network."

VPI also provides this capability in the form of its VPI Transport Maker. "Any of the long-distance networks in the United States-AT&T, Sprint, MCI WorldCom, Level 3-they have hundreds and thousands of miles of fiber, and pretty much any conceivable network could be built on top of that," explains VPI's Harshavardhana. "So what is the best option for them, given all these choices? What we do is build software tools that let you analyze the various available architectural and technological options and combine these options in an effective way to do various kinds of 'what if' analysis that lets you figure out what is the best strategy for you," he says.

A key market-driver network-level design software, according to Lalk, is the tremendous pressure facing local-exchange carriers. They need to be able to optimize the performance of their networks. "For a while, they were playing this game where they were just getting into the business, and now they are going to have to be more efficient at doing their business than their competitors," she contends. "So they are looking for software that helps them understand how their networks are performing and, more important, how they perform at better costs.

"For service providers, it becomes a margins business," says Cohen. "They have to be as cost-effective as possible in order to compete."

Design software facilitates innovation in the network. "Without a huge cost, somebody who is trained on one of these tools could plug in new components and see how they affect their networks, not just their performance but their cost and economic outlook," explains Lalk. "I think that's going to be pretty important as we go down the road. We see lots of new technologies every day, every month, and people have to be able to quickly plug those in and say, 'Okay, should I change something in my network without it costing them an arm and a leg?'"
Cohen expects that in the future, OPNET's design software, for example, will start to blend with the operational software in the network operations center. When a failure occurs in the network, for example, the software will perform an impact analysis to determine the most optimal way to restore the network. Cohen also sees his company's design software playing a sales role in the future for service providers, who may use the software on a daily basis to help sell services.

Design software is the language that enables innovation and communication among everyone and anyone involved in any aspect of component and network design or deployment. For success in today's market, it is absolutely critical.

"I've been in meetings with people who are planning networks, and they say, 'Oh, but the fiber doesn't go that far,'" says Lowery. "Being a physical-layer person, I say, 'Of course, it does! That's easy.' Whole networks have been designed using out-of-date information. The key is to get the information flow rapidly into the network."

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