By ROBERT PEASE
The telecommunications industry, despite having seen better economic times, still faces increasing bandwidth demand. Service providers must accommodate continuing traffic growth to remain competitive, yet it's almost a battle of wills to see who will make the first move to ensure that today's networks can meet tomorrow's needs. In a new environment where cost and revenues rule, some providers are finally giving a serious listen to the advantages of end-to-end all-optical networking.
The definition of an all-optical network (AON) can be as complex as actually building one. In short, all-optical networking is transporting network traffic end-to-end from point A to point B without the use of any electrical conversion. In its purest sense, an AON is still a myth, since bits-1s and 0s-cannot be touched optically. But in the sense that an AON minimizes electrical conversion while extending the reach of the network with less regeneration, the industry seems headed in that general direction.
"The enablers are already in place for the realization of AONs," says Frank Galuppo, vice president and general manager of the optical long-haul solutions division at Lucent Technologies (Murray Hill, NJ). "Tunable lasers are emerging, ultra-long-haul systems are extending their reach and eliminating the number of regenerations, optical switches are far more flexible, and Raman amplification is available. All of these will contribute to a considerable drop in capex [capital expenditures] and, eventually, opex [operational expenditures]. The real question is whether applications will emerge to make AON a reality."
Among vendors of optical-network transport gear, migration to an all-optical infrastructure is not only possible, but also necessary for exploiting the market opportunities that will soon arise for bandwidth, flexibility, reliability, and network-management functions. Network topologies will require a "mix and match" of optical switching, DWDM, and SONET/SDH, along with new migration technologies, many of which are still being developed.
In the end, however, the AON equipment must meet the needs of carriers-the most demanding need being affordability. "The goals of AON should be to eliminate network components and make the network edge protocol-agnostic-the more optical, the better," says Balan Nair, vice president of emerging technology at Qwest Communications (Littleton, CO). "The challenge is to transition the embedded copper base to AON."
Once accomplished, says Nair, the AON can potentially provide huge revenue opportunities. Fiber-to-the-business will become a reality much sooner, followed by fiber-to-the-home. A key enabler will be passive-optical-network (PON) technology, coupled with free-space optics, to make time-to-market even shorter for new services.
Proponents of AON may differ when discussing its future in telecommunications. How will it evolve? Where will it be a logical choice? How pure a form will "all-optical" take? But with the emphasis on lowering costs and increasing revenues in today's optical networks, AON is definitely moving forward.
Carriers face huge decisions in how to invest their capital, while vendors strive to offer equipment that will ultimately help providers stay in business and compete. At some point, the challenges of bandwidth demand will no longer be constrained and the hands of both carriers and vendors will be forced. That final decision will likely include AON in some form-and the all-optical era will begin.