BROADBAND COMMUNITIES is the leading source of information on digital and broadband technologies for buildings and communities. Our editorial aims to accelerate the deployment of Fiber-To-The-Home and Fiber-To-The-Premises.
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70 | BROADBAND COMMUNITIES | www.broadbandcommunities.com | JANUARY/FEBRUARY 2014 TECHNOLOGY DOCSIS Provisioning of EPON (DPoE) standard enables cablecos to use their existing back-ofce systems over EPON networks, which they can't do with GPON, and a number of them are now incorporating EPON into their networks, especially for business services. (Vanhastel explains, "Tey could have done a DPoG – DOCSIS Provisioning on GPON – standard, but they didn't.") Tough 10 GPON equipment has been available for two years and telcos have tested it, they are not yet using it, and very few have plans to deploy it. Vanhastel says, "GPON has enough bandwidth for the moment, so there's no real urgency." In fact, some telcos are discussing whether to skip the current generation of 10 GPON (10 Gbps down, 2.5 Gbps up) and wait for the next generation (10 Gbps symmetrical). WDM-PON: READY FOR TAKEOFF? Several years ago, wavelength-division multiplexing (WDM) PON equipment began to appear on the market, and this technology – or collection of technologies – was hailed as the answer to all conceivable bandwidth constraints because it essentially multiplies the capacity of each fber by 40. Today, however, though some companies use WDM- PON in special circumstances to serve business customers, none have deployed it widely. Rob Adams, vice president of product management at Transmode, a Swedish provider of packet-optical networking solutions, explains, "Tere was no inexpensive way to deliver a wavelength to each premises. Te expensive part was the optics." Still, Adams believes there is a strong need for wavelength services for businesses and for wireless backhaul (and, eventually, for residential service). Cell tower backhaul requirements, in particular, will rise dramatically with the introduction of LTE Advanced, a standard that is currently in trials. "Most operators acknowledge 1 Gbps isn't far-fetched, so they don't want to deploy any other type of PON knowing they'll have to do a forklift upgrade," Adams says. "And active Ethernet is expensive from the infrastructure side. Te beauty of WDM- PON, given the uncertainty in bandwidth requirements, is that essentially you're unlimited in bandwidth without dramatically changing the infrastructure." Now, Transmode may have cracked the code for reducing the cost of WDM-PON optics sufciently to make the technology viable. Its new solution uses an injection-lock laser that automatically locks to whatever color light it sees. Injection locking itself is not new, but Adams says, "We found an inexpensive way to project colored light for the injection- lock lasers so they'll automatically see the color of the light and lock to that frequency. Not only is it really inexpensive, but also, because you're automatically tuning the laser, you get rid of all the wavelength tracking. From an operational standpoint, you eliminate the need to track the wavelength." Setting up a connection requires simply inserting an optical plug into an OLT in the central ofce and another one into an ONT at the customer premises. As long as the two ports have the same number, they will connect over the same wavelength. Until they are plugged in and lock onto a wavelength, all optical plugs are identical – which means operators must carry only one type of plug in inventory, instead of 40. "We're getting interest in this technology everywhere," Adams says. "We think it's going to take of now." v Masha Zager is the editor of BroadBand Communities. You can reach her at email@example.com. WDM-PON failed to take of in large part because the optics were too expensive. A new solution ofers the promise of inexpensive optics and interchangeable parts. BBC_Jan14.indd 70 1/27/14 1:48 PM