Fiber-Optic Technology Could Benefit Computer and Electronics Test Equipment

December 1, 2008

An innovative technology capable of moving data faster within high-end computers may soon benefit the multi-billion-dollar electronics test equipment market. Using a patented fiberoptic polymeric ribbon technology, circuit boards, central processors, and memory can be optically interconnected for faster data transfer within computer systems.

Missile Defense Agency (MDA) funded New Span Opto- Technology of Miami, FL through a 2004 Small Business Innovation Research (SBIR) Phase II contract to develop a fiber-optics component for military computer systems that can relay high rates of data. Sophisticated data acquisition and analysis systems often include a number of plug-in modules to perform dedicated tasks, such as signal processing or image processing. The central processor must synthesize the data from many such sources. As the capabilities of the electronics increase, a data bottleneck occurs unless the supporting components can communicate at sufficiently high rates.

How it Works

Conventional interconnect systems, which use conductive cables or copper traces (the conductive paths etched into the copper cladding of a printed circuit board), have reached their inherent data-rate limit. Optical couplers, the optical equivalent of electrical connectors, can fill the need in high-end systems for military processing and commercial test equipment such as digital oscilloscopes — instruments commonly used to view and compare very high-speed electrical signals.

While there are many commercially available optical systems, New Span has come up with an innovative way to couple light into its multichannel ribbon waveguide using a bus architecture not feasible with other interconnect systems. In a conventional system, light traveling in an optical waveguide on the main board is reflected into the plug-in module — a one-to-one connection from source to destination. A second module would require a second waveguide channel.

New Span uses a different ap - proach that is analogous to the electrical bus systems used in standard computer designs, reducing the complexity of the optical system. Using a phenomenon known as evanescent coupling, some portion of the light energy in the main waveguide is tapped off by the coupler and directed to the destination. The remainder of the energy can continue down the waveguide to where it can tap in to additional couplers. This analogous bus structure reduces the complexity of the optical system and allows designers to continue using a well established and familiar computer architecture.

Where it Stands

New Span estimates the use of the optical ribbon will improve the speed at which a computer's microprocessor can communicate with its peripheral devices from an average of 800 megabits per second to as high as 30 gigabits per second.

The company's early testing of the technology with a 12-channel, high-speed signal generator demonstrated that undistorted signals can be captured at speeds of up to 2.5 gigahertz per channel, or a 30 GHz aggregate rate. The company expects further improvements in the technology to provide as much as a four-fold increase in speed, corresponding to 10 GHz per channel.

New Span's most likely market outside of defense is the electronics test equipment industry. Specifically, digatal oscilloscope manufacturers are prime commercial tagets. The company's technology also might benefit personal computing by using fiber-optic ribbons to separate dual-core or multicore processors, which are closely stacked in today's systems. The tight stacking makes it difficult to remove heat from the devices. New Span's technology would allow the processors to be separated for better thermal management without sacrificing data transfer speed.

The company is hoping to locate companies — namely prime computer manufacturers — that would be interested in partnering and licensing its technology.

More Information

For more information on New Span's fiber-optic ribbons, click here  . (By Joe Singleton/NTTC; Source: MDA TechUpdate, Missile Defense Agency, National Technology Transfer Center Washington Operations.)

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