BY Skyler Frink
As the amount of data being processed grows, so does the speed at which the data needs to be processed. Optical interconnects, which use light rather than electrical signals, are becoming increasingly popular with military systems designers.
“They’re making a lot of demands today,” says John Lee, vice president of sales and marketing at Timbercon Inc. in Lake Oswego, Ore. “It’s growing exponentially.”
Of course, there are many reasons for this switch, but one stands out above the others. “The main reason to use optical interconnects is for high speeds,” says Jose Silver, an applications engineer at Glenair Inc. in Glendale, Calif. “It’s a technology where you can maximize your data per second.” At current levels of technology, optical interconnects can transfer more than 40 gigabytes of data per second.
While copper wire is cheaper than optical equipment and costs of short-range optical interconnects have been trending downwards at a rapid pace, the differences in performance are clear. For the defense industry, which requires products on the cutting edge of technology, whether copper or optical interconnects should be used is an obvious choice.
One mil-aero application that demonstrates the benefits of optics is unmanned aerial vehicles (UAVs). “Drones send a lot of information,” says Timbercon’s Lee. “The only real way to do it is through optics.” For unmanned vehicles, using a connection that can deliver 10 gigabytes per second from 500 meters away is extremely useful, and something optics have already achieved.
In the defense industry, security is a primary concern; this is an area where optical interconnects have a leg up on copper. While electrical signals are vulnerable to electromagnetic interference (EMI), optical interconnects are not. Optical interconnects do not require shielding, which allows for smaller, lighter devices.
Electromagnetic fields, which copper connections can emit, can represent an opportunity for electronic eavesdroppers—even from normally innocent devices, such as keyboards. While shielding can help mitigate this, electromagnetic fields remain a serious security risk in any field that requires maximum security. While optical connectors do give off stray signals, they are not nearly as easy to detect or gather information from as are copper connectors. “The beauty of fiber is it’s very hard to tap into those signals,” Lee says.
As with any new technology, optical interconnects require training to install and maintain. “Our biggest hurdle is education,” Lee explains. “There are a lot of people that know copper but don’t know fiber at all.”
The major difference between optics and copper involves contamination. Optical connections must remain clean, because dirt and dust can severely limit the amount of light—and, hence, the amount of data—traveling through cables.
Introducing optical interconnects into systems that already use copper can be a daunting task; for many companies the question is how to integrate optical interconnects when they already use copper, yet a recent technology has helped solve the problem. “There’s a new adaptor that can convert copper signal to an optics signal,” says Glenair’s Silver. These adaptors, called media converters, can change a copper signal into an optical signal at the blink of an eye.
Adopting the new technology has been slow, however. “We have a lot of legacy connectors in the field,” Lee says, adding that the U.S. military has been slower than most with the switch to optical interconnects. The U.S. Air Force has been an exception, however, and has already been making the switch to optics.
The Air Force has moved to fiber, Lee points out. “It’s lighter, smaller, has no EMI, and doesn’t cause sparks.” Sparks and EMI can be extremely dangerous. “In the military, they’re catching up,” Lee says. “Warfighters today have a huge appetite for data; if we don’t have that type of bandwidth, we won’t be giving our warfighters everything we can.”
The military is slowly but surely shifting to optics, but Lee says he is worried about potential cuts to the U.S. Department of Defense budget, which he says could slow any transition of copper to fiber.
While the U.S. military has yet to switch over, most modern technology is moving toward the use of optical interconnects. “Everybody wants more speed, more bandwidth, and smaller devices,” Silver explains. “I think optics have a long future ahead of them.”
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