Post-deadline papers show commercial edge

Trends in research reporting can foreshadow technology markets.

If the "hero" experiments that dominate conference post-deadline papers were an exact predictor of market trends, then we could soon expect to see carriers deploy all-optical 160 Gbit/s systems. Of course that's not the purpose of the papers or the experiments they describe, which often push a technology well beyond expected operating conditions so it can be refined and proven for real-world applications.

Perhaps a quarter of the 47 post-deadline papers at the Optical Fiber Communications (OFC) conference (Atlanta, GA; March 23–27) could be called hero experiments—that is, experiments in which research teams test a system's performance and capacity by pushing ingredients such as distance, speed, modulation format, and channel spacing. Most take place in the lab, but one real-world hero experiment was performed by researchers at Tyco Communications (PD27). Their field trial ran 128 channels at 12.3 Gbit/s over a single dispersion-flattened fiber between Hillsboro, OR, and Toyohashi, Japan, a distance of 8991 km. This wasn't the most heroic of experiments, but it was impressive because it demonstrated terabit-per-second-per-fiber capacity on an installed undersea system.

Optical magic

All-optical regeneration has been on the industry wish list for many years because it would eliminate the expensive optical-electrical-optical (OEO) conversion now necessary to reamplify, reshape, and retime (3R) optical signals. An all-optical regenerator would extend transmission distances and, if it had wavelength-shifting capability, allow carriers quickly to reconfigure their networks, including optimizing use of the many different types of fiber in their networks.

Three post-deadline papers at OFC dealt with all-optical regeneration. The approaches varied from a nonlinear fiber-based 2R regenerator and dispersion compensator operating at 40 Gbit/s from Corning (PD05), to an Alcatel 3R regenerator based on cascaded semiconductor optical amplifiers, also at 40 Gbit/s (PD15). A Fujitsu/Heinrich-Hertz Institute team created a fiber-based wavelength-shift-free 3R regenerating repeater operating at 160 Gbit/s (PD16).

As for post-deadline papers foreshadowing commercial products, on the OFC exhibit floor Lightbit launched the first commercial all-optical 2R regenerator. Lightbit CEO Larry Marshall said carriers and OEMs are quite interested in the product for next-generation 10 Gbit/s systems. He acknowledged that 3R regeneration is better than 2R, but argued that the third R—retiming—adds substantial expense and is not necessary for distances in North America. The regenerator is based on a buried waveguide in a magnesium oxide-doped lithium niobate wafer.

Making the cut

The line between such commercial products and "research" is a bit blurry in the post-deadline world. In the case of researchers from Ahura, the fact that a post-deadline paper was accepted at OFC motivated them to come out of stealth mode and discuss their high-power incoherent Raman pump module (PD47). Marketing director Eric Schmidt says the company saw the opportunity when the post-deadline committee selected them on the basis of their use of a broadband source to replace a pump laser and the fact that their distributed Raman amplifier fits in a butterfly package.

The selection process for post-deadline papers happens quickly but methodically, according to OFC technical chair Tom Afferton of AT&T. He and co-chair Doug Baney from Agilent Labs led the nine technical committees that selected all conference and post-deadline papers. Afferton says the acceptance rate for OFC post-deadline papers has remained the same over the years at about 40%.

I wondered if the committees had a natural predilection for hero experiments. Afferton assured me that the selection was based strictly on the papers submitted. Hero experiments—rather than more theoretical work or research requiring greater explanation—simply lend themselves to the short, breaking news captured in post-deadline papers.

The first criterion for post-deadline papers in all fields is that they advance the science or technology. From the evidence in the telecom world, commercial potential is a reasonable second.

Conard Holton is editor in chief of WDM Solutions, and executive editor of Laser Focus World; e-mail:

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