Optical Fibers Go Active

KVH Industries Inc. (Nasdaq: KVHI) hopes to make a splash at OFC next week when it introduces a 40-Gbit/s optical modulator based on an all-fiber technology.

Reportedly, it's taken KVH three years to reach the heady heights of exhibiting at OFC. In 1997 the company purchased the intellectual property ownership of a proprietary optical fiber from Andrew Corp.. This includes the technology for making "D-shaped" optical fiber -- a fiber with a flat side -- which makes it possible to etch into the core of the fiber, according to Jim Dodez, KVH's vice president of marketing.

The next piece of the jigsaw to fall into place was the discovery in April 2000 of electro-optic polymers that could be modulated at speeds up to 100 Gbit/s. Larry Dalton, a professor at the University of Washington, whose research team made the breakthrough, is now on KVH's advisory board.

KVH removes a section from the core of the D-fiber and replaces it with a piece of electro-optic polymer, which it buys from Dalton's lab, says Dodez. Then, it makes a groove in the opposite side of the fiber from the flat of the D, and inserts an electrode. With no applied voltage on the electrode, the polymer remains clear. When a low voltage is applied, the polymer goes dark. This way, a data signal applied to the electrode is easily converted into an optical signal.

Plenty of other companies are using Dalton's materials (see Polymer's Progress) so KVH will have strong competition in terms of the performance of its device. But other companies are spraying the polymer onto silicon chips, to make planar devices.

A simple head count of who is doing what might suggest that the planar approach is better than the all-fiber design. But Dodez thinks otherwise. "Since the optical signal never leaves the fiber core, the insertion loss of the modulator is reduced, permitting either increased span lengths or lower-power light sources," he says. He also believes that "ActiveFiber" as it is called, could have much higher manufacturing yields than conventional electro-optic chip processes -- though that's impossible to prove at this stage.

Later this year, says Dodez, KVH is planning to unveil other all-fiber products, including variable attenuators, tunable fiber Bragg gratings for add-drop multiplexers, and possibly NxN optical switches.

KVH claims it is one of the few companies that both makes its own fiber and manufactures components and systems. Its current product lineup comprises navigation systems, broadband satellite gear, and fiber optic gyroscopes. In 2000, KVH had revenuess of almost $30 million and net profit of $76,531.

— Pauline Rigby, senior editor, Light Reading http://www.lightreading.com

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