CHARLTON, Mass., April 9 -- FiberCore, Inc., a manufacturer of optical fiber and preforms for the telecommunication and data communication markets, reports that an independent arbitrator has ruled in its favor in a 1998 patent infringement claim brought against the company by Corning. Corning had alleged that certain single mode fiber sold by FiberCore in the United States infringed a Corning U.S. patent. The arbitrator ruled that FiberCore's single mode fiber did not infringe the patent in question, which is due to expire in July 1999.