In an article that will appear in the August issue of Cabling Installation & Maintenance magazine, OFS product manager for multimode optical fiber John Kamino will describe five reasons users should not install 62.5-micron (OM1) fiber in their networks. Kamino, who previously authored the popular article “Making the switch from 62.5- to 50-micron fiber,” points out that OM1 fiber “comprises more than 25 percent of the multimode fiber sold in North America, and more than 30 percent of the multimode fiber sold worldwide.” The question is, why?
After providing a recap of multimode fiber’s evolution from OM1 to OM4, the article cites five common reasons users give for continuing to install new OM1 fiber today. It then provides an explanation of why, in each case, a better-performing fiber should receive serious consideration. We won’t divulge every detail here—because we want you to read the full article when it’s published in August—but we will provide each of the five points, and Kamino’s counterpoints, in a nutshell.
Reason 1: It’s only a cable extension for a low-speed network.OK, Kamino says, but if it’s being installed for more than just a passive connection (i.e. if the new OM1 cable is actually going to be connected to any active networking equipment), use OM3 or OM4. “When the time comes to upgrade the lower-speed links," he says, "the new OM3/OM4 fiber can remain in place, but the older OM1 cable will probably require replacement.”
Reason 2: OM1 works well for the speeds I’m installing today.Cabling installations are meant—and expected—to last for 10 to 25 years. Will you still be running the same low speed 10 to 25 years from now? With the typical network-equipment replacement cycle being five years, you can expect two to five equipment replacements over the lifetime of your newly installed cable.
Reason 3: OM1 is what’s currently specified.Generic specs provide guidelines for suppliers, but they have limited value if they are not updated to include recent technology improvements. If a current specification hasn’t been updated recently, it’s not serving the user well.
Reason 4: OM1 is cheaper than OM3/OM4.That’s true, on a first-cost basis. But installation costs often are equal—and sometimes higher for OM1. And if (or when) that OM1 has to be replaced to support higher-speed gear, any initial savings have disappeared.
Reason 5: OM1 has better macrobend performance than 50-micron fiber.Historically, that was true of the fiber itself and the cabled fiber in many cases. But the cabled attenuation of 50-micron fiber is now better than that of 62.5-micron OM1. Plus, the introduction of bend-optimized or bend-insensitive multimode makes 50-micron’s macrobend performance far superior to that of 62.5-micron OM1.
Please look for the complete article in the August 2013 issue of Cabling Installation & Maintenance.
