Major optical fiber manufacturers have invested $2.6 billion in plant expansions that will nearly double the capacity available in 1999, according to a study by KMI Corp. titled "Worldwide Markets for Optical Fiber and Fiberoptic Cable."

Worldwide capacity will reach 152 million fiber-kilometers next year, the study says, with most of that capacity going to satisfy an estimated demand for more than 111 million km of cabled optical fiber.

The study says continuing growth in optical communication means that fiber manufacturers will have to invest $3.7 billion in additional expansions in 2003 and 2004 to stay ahead of demand.