18 November 2005
18 November 2005
The University of Delaware’s Center for Composite Materials is to work with the Army Research Laboratory on a project to develop micro-scale optical devices in composite materials.
When Keith Goossen joined the faculty at the University of Delaware , he brought with him 14 years of industrial experience in the fields of optoelectronics and optical fibre communication, which he is now applying in this new project. For Goossen, whose focus has been on technology rather than systems, leaving industry and joining academia has presented the opportunity to turn his attention toward a feature-based application of that technology rather than focusing simply on improving speed and performance.
In his project, the feature-based application is smart materials. “Typically, the term smart material implies embedding of sensors or electronics to enable evaluation of what's going on in a material,” he explains. “But we're expanding that definition to encompass materials that can actually perform communication and computing functions.”
Goossen has coined the phrase “fabric area network” to capture the concept: “These composites are typically composed of a fibreglass fabric, and our goal is to create a composite structure that comprises a self-contained LAN in itself,” he says.
He likens it to a “smart house,” pointing out that with current construction practices, the structural elements of a house are erected, and then the house is wired for computing and telecommunications as an add-on. “Our goal is to integrate these features into the structure so that it's fully functional for whatever is required by the application.”
For the Army, the applications include hulls of tanks, ships, and helicopters. The potential also exists to apply the technology to soldier personal protective equipment, including clothing, armour, and helmets.
While the concept of a helmet that incorporates communication and computing functions is certainly intriguing, the path from concept to realization is riddled with challenges, including issues associated with manufacturing and power requirements. Goossen's industrial experience has sensitized him to the importance of addressing these technology transfer issues as he proceeds through the research.
One of his first steps in this project was to work with industry on the feasibility of weaving optical fibers. “This had been done using manual and semi-manual approaches before,” Goossen says, “but we were successful at using a weaving machine to embed the fibres into the fibreglass fabric.”
“In itself, that didn't prove much,” he continues, “because there has to be a way to connect to the fibres once they're embedded in the composite. So we're now investigating optical techniques for interfacing with the embedded fibres. Our current work is in the near-infrared range.”
The research has demonstrated successful communication into and out of the network optically without a physical connector. “That's the good news,” says Goossen. “The bad news is that we're still bringing electrical power in through wires. While wireless technology obviously exists, we want to avoid it for security reasons. Ideally, we'd like to achieve the flexibility of a wireless network with the security of a wired one.”
Goossen's approach to that problem is the use of a transponder comprising a photodiode detector and a laser to send the resulting signal along the embedded cable. “The powerless transponder makes life a lot easier,” says Goossen, “because it can be put anywhere on a structure, and it doesn't have to penetrate the structure to communicate.” Thus far, inputting of data has been more successful than retrieval, but Goossen is working to determine the best approach for extracting data from the system.
Future spinoffs of the technology include remote interrogating of sensors for a myriad of applications. Goossen is also intrigued by the idea of developing an optically capable circuit board.
“A circuit board is basically a composite material,” he says. “Five to ten years from now, when the bandwidth catches up with the technology, we can use this capability in high-performance computing by transporting an optical signal along a circuit board.”
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