CORNING, N.Y., Jan. 19 -- Corning Inc., W.L. Gore & Associates Inc. and Siecor reported that in recent tests, a prototype multimode fiber demonstrated serial transmission at both 1 and 10 Gb/s. The test employed Corning multimode fiber and Gore's high-speed 850-nm vertical cavity surface emitting laser (VCSEL) technology. The fiber -- which the companies described as best suited for high-speed transmission at Gigabit Ethernet speeds or higher -- is a prototype InfiniCor fiber optimized for 850-nm operation.This test followed an August 1999 demonstration in which Corning and Gore achieved 600-m serial transmission at 10 Gb/s. The most recent test attempted to better simulate real world system conditions; Siecor cabled the fiber, and multiple connectors were used in each experiment. The 850-nm VCSEL was coupled to the fiber and the output pulses, which were converted into electrical pulses, displayed the bit pattern on an oscilloscope in the form of an eye diagram. The companies said the eye diagrams illustrated a clear, open eye for both 1- and 10-Gb/s modulation.