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Fiber Optics

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Type: Article, Report or Whitepaper

Topics: AV Equipment; Education; Government; Healthcare; Installation; Video

Date: December 2010

Fiber optic networks are showing up in AV installs at an increasing rate, driven by the need to transport a large amount audio, video and data over a long distance. Historically, copper-based networks have been able to meet the demand but advancements in technology and changes in consumption behavior of content like high-definition video streaming has pushed the capacity of copper cables to their limit. Fiber optic cables and fiber optic networks are the obvious remedy to the increasing bandwidth needs of today's users but the use of fiber optics is still fairly new to the AV industry.

Previously, fiber optic networks were typically deployed in government or military applications for security reasons. Fiber optic cables and fiber-based network components were so cost-prohibitive that they were rarely seen outside of these venues. "The rising cost of copper and the price drops we've seen in fiber optic endpoints is bringing fiber optic network costs in parity with copper-based networks," explains Daniel Jackson, research and development engineer at Crestron. Jackson is the chief inventor of Crestron's DigitalMedia line of fiber optic network products. "Lower costs, plus networking and digital video driving adoption, means that fiber optic networks are increasingly considered normal in most applications."

Yanik Reid, design engineer for Magenta Research, says that the primary issue for AV installers is educational. "Installers feel more comfortable with copper if that's what they've always known," he notes. "Fiber optic cables are perceived to be much more sensitive than copper cables, so the proper training is necessary."

Fiber Optic Cables and Networks
How is fiber optic cable different from copper cable? "From a scientific perspective, copper cables carry electrons whereas fiber cables carry photons. AV installers are dealing with the same concepts with troubleshooting and best practices, but procedures and tools are different," says Jackson.

There are three types of fiber optic cable used in the marketplace - single mode, multimode and plastic optical fiber. Typically, the fiber cable's core is made of glass or plastic. In a fiber optic network, a transmitter outfitted with LEDs or lasers are used to transmit the data as light. Similar to a copper-based network, networking components include routers, switchers and receivers.

As with copper cables, there are several types of fiber optic cables. AV installers will most likely work with fiber optic cables that meet the EAI/TIA 568 standard for premises cabling as set forth by the Fiber Optic Association. This standard clearly outlines fiber types and performance benchmarks that all fiber optic cables must meet during testing.

Differences with Copper Cables
While the high cost of fiber optic cables and endpoints is less of a prohibitive factor, it is notable to point out the major differences between fiber optic and copper cables. There are three main areas where fiber excels over copper: security, bandwidth, and distance.

"In addition, with fiber based systems there are no ground loops. This might be why a campus (business or educational) might choose to go with fiber, even if the buildings are not that far apart," adds Chris Kopin, vice president of product development for Kramer Electronics. "But the important reason to deploy fiber optic cable is distance. As fiber can carry signals to much greater distances than copper solutions, it is required when a long distance must be obtained. In many broadcast applications that is the case."

Reid also says that fiber cables aren't susceptible to electromagnetic interference (EMI). "You don't have to worry about your cable installed next to a power cord, for example. There's no noise interference," he says. "Fiber optic cable also has much more bandwidth capability than copper, so it's unlikely you'll need to change a fiber cable for an upgrade once it's installed."

Kopin adds, "Unlike copper transmission, fiber optic is secure. It is a must in applications where security is of utmost importance, like in government and military environments."

According to Jackson, it was an eye-opening experience when Crestron debuted its DigitalMedia products in 2009. Both cable suppliers and customers were confused about the AV industry's needs when it came to fiber optic networks and the differences with copper-based networks. As a result, Jackson and his team spent time developing an educational course about their products and about fiber optic networks so that AV installers could better understand and communicate about fiber optics.

Jackson notes, "Learning fiber is easier if you've never known copper. The install concepts are the same but the tools and lingo are different. For example, continuity checker for copper cables versus visual fault locator for fiber cables."

Advantages in AV Applications
In addition to government and military applications, vertical markets like corporations, education, and healthcare are deploying fiber optic networks. "Hospitals like fiber optics for noise immunity, reliability, and the small cable size; higher education institutions use fiber optic networks throughout buildings as broadcast video networks to record and stream every class," explains Jackson.

Fiber optic cable has been a great solution for AV installs that require cable runs over 1,000 feet, the maximum distance for Cat5 cabling. "Sometimes we need fiber solutions when we need to just go a little further than a copper solution will allow. Typically in AV, we may need to go as much as just another 1,000 feet," says Kopin.

"Historically, the AV industry has used multimode cables and solutions since they have been significantly less expensive. In the last couple of years, that price difference between multimode and single mode has dissipated. Now that the cost of multimode and single mode cables and processing chips are very similar, we will probably see a migration by manufacturers to single mode solutions in our business. Even though we have previously established that in AV applications, we only typically need a fraction of the distance fiber optic solutions provide, we will still see a move to single mode all things (cost) being equal."

Pre-terminated cables are often used in AV installations since terminating fiber optic cables in the field can be complicated and expensive. It puts more pressure on the planning stage, with labor costs offset by quick, one-wire cable pulls of pre-terminated, pre-measured cabling. While fiber optic cables are sturdy, it also should be noted that fiber cables have specific bending radium, and will sometimes break if the cable is bent beyond spec.

For general overall cost and convenience issues, Kopin thinks that copper-based networks for AV applications up to 1,000 feet will remain the typical solution recommended and deployed. "Fiber will be relegated to the very long distance applications, the high security applications and the critical applications where ground loops are unacceptable under any circumstance," he says.

Meanwhile, Jackson takes a more pro-fiber optics stance. "All contractors should make fiber optics part of their core competency. Fiber is better in every way except cost, and that will soon change as prices drop," he notes. "The fiber optics adoption curve for home and commercial is about two-thirds copper and one-third fiber optic cables right now. That will tip more to fiber on the commercial AV side since fiber also helps future proof and provide cable standardization."


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