ADVA Unleashes WDM-PON

BRUSSELS -- Broadband World Forum Europe 2008 -- ADVA Optical Networking (Frankfurt: ADV) kicked off what is likely to be an avalanche of WDM-PON (wavelength division multiplexing - passive optical network) announcements here in Brussels with the unveiling of its upcoming Unifier (Universal Fiber Access Extender) architecture.

WDM-PON, which enables a dedicated, rather than a shared, wavelength to an end user, building, or neighborhood, has emerged as one of 2008's hot technologies, with carriers and vendors engaging in trials, tests, and product developments. (See FT Lauds WDM-PON's Potential, WDM-PON Faces 10G Challenge, Nortel JV Buys WDM-PON Specialist, Ericsson Joins Cost-Cutting WDM-PON Team, and WDM PON: Sooner Rather Than Later?)

Now ADVA has joined the fray. But while other companies are looking a few years out to commercial product launch, ADVA is talking about early next year.

Unifier, which is set for commercial availability in early 2009, comprises a so-called Flexible Remote Node (FRN), which sits in a local exchange/central office (or even closer to the customer), and a further active element (ADVA's Etherjack device) or passive element (ADVA's Optojack, also announced today) at the customer premises that provides demarcation and monitoring capabilities.

The demarcation/monitoring device, in the form of a small form-factor pluggable (SFP) component, would be integrated into a network element as close to the end user as possible: It could be housed in a multiservice access node (MSAN), an Ethernet switch, a VDSL2 multiplexer, or in the case of large business users, into an ONT (optical network termination) unit.

The FRN acts as the link between the metro optical gear and the transceiver at the customer site, enabling passive connections all the way to the very edge of the network.

The aim, says Stephan Neidlinger, ADVA's director of applications and solutions management, is to enable symmetrical bandwidth (at least 100 Mbit/s each way), reduce the number of active elements in the access network, cut operational costs for carriers looking to build out fiber access networks, and bring all the backhaul traffic onto a single fiber connecting the FRN and the metro optical switch.

The essential proposition is that the WDM-PON equipment in the local exchange enables high-capacity aggregated backhaul connections from the customer premises, street cabinet, or wireless base station, to the metro core with a minimal number of network elements.

ADVA's cost analysis case studies show the WDM-PON Unifier architecture offering an advantage over VDSL2 and GPON architectures that use CWDM gear for backhaul. That might not sound right to those following PON infrastructure pricing trends, as WDM-PON components are generally believed to be at least three times more expensive than GPON components, for example.

ADVA admits that initial hardware costs will be more expensive, but contends that, while the Unifier approach involves a higher initial capex outlay, much lower OAM (operations, administration, and maintenance) costs and reduced power consumption make it about 25 percent cheaper to install and operate than traditional VDSL2 or GPON architectures.

However, ADVA is only basing these projections on case studies -- the Unifier concept has not yet been trialed by any operators.

— Ray Le Maistre, International News Editor, Light Reading