The state of next generation optical networking

Broadband build-outs have taken center stage in telecom discussions recently, due to the inclusion of federal grants for broadband expansion in the stimulus package. The stimulus package outlined $7.2 billion in funding for broadband build-outs, but advisors in the Obama administration, such as Blair Levin, were quick to point out that any broadband stimulus money would just be the beginning of the administration's commitment to providing ubiquitous broadband access in the U.S. Will consideration be specifically for current buildouts, or more generally for broadband architectures, including next-gen optics?

Current optical networking standards such as GPON and EPON are getting a significant upgrade in capacity through efforts of the ITU and IEEE, standards groups that vet and test an optical network standard before widespread deployment. These new deployments have the ability to drastically increase the downstream and upstream bandwidth capabilities of a network, in some cases resulting in a 10-fold increase in capacity.

We'll take a look at the standards that are currently being developed, and see what they could mean for telecom vendors, carriers, and customers in different areas of the world. 

Standards History 

PON refers to passive optical networking, in which unpowered optical splitters are used to enable single optical fibers to serve dozens of end points. Currently, Gigabit PON (GPON) and Ethernet PON (EPON) are the main standards used in optical networking deployments, taking over share from Broadband PON technology, which has considerably less capability.

For instance, Verizon's FiOS fiber-to-the-home offering originally used BPON plants, but has since switched to GPON technology, which has 2.5Gbps downstream and 1.2Gbits upstream capabilities, up from 622Mbps/155Mbps with BPON.

While GPON has proven more popular in North America and Europe, Asian carriers have instead deployed EPON en masse. The push for next-generation standards comes as some carriers in Japan, China and South Korea have reached the limits of their 1G EPON plants and want more capacity to provide high-end video solutions and other data-heavy applications to areas with extremely high population density.

On July 19, 2006, the IEEE announced objectives for the new standard, referred to as IEEE P802.3av, which included supporting subscriber access networks using point-to-multipoint topologies on optical fiber and providing physical layer specifications for 10 Gbps downstream/ 1 Gbps upstream and 10Gbps downstream/ 10 Gbps upstream PONs.

On June 25, 2008, PMC-Sierra announced the industry-first demonstration of 10G EPON. Currently, the standard is in its final stage of review, with evaluation boards having been shipped to customers and carriers in early 2009. All analysts and vendor representatives surveyed for this article were optimistic that the standard would be finalized by the end of 2009.