IEEE Computer Volume 15 Number 3 -- NEW APPLICATIONS & RECENT RESEARCH
Original Publication Date: 1982-Mar-01
Included in the Prior Art Database: 2005-Nov-11
Software Patent Institute
Demetrios Michalopoulos: AUTHOR [+2]
NEW APPLICATIONS & RECENT RESEARCH * Fiberoptic telecommunications system reduces need for signal regeneration * Apple 11 and interface card help omsite researchers * Wana Laboratories spoke; E. F. Hutton listened * Graphics program ";sculpts"; tubular steel for artist
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NEW APPLICATIONS & RECENT RESEARCH
New Products Editor: Prof. Demetrios Michalopoulos
California State Universitv. Fullerton
Fiberoptic telecommunications system reduces need for signal regeneration
By using new lasers and new cabling, and shifting to a different infrared wavelength, General Telephone & Electric has developed a fiberoptic telecommunications system that reduces, and in some cases eliminates, the need for signal regenerators along optical cable routes.
Most of the systems in use today employ a part of the infrared spectrum where the light waves are 850 nanometers in length. These systems require the placement of signal regenerators at 10-kilometer intervals along their cabling because the I R signal pulses begin to weaken and lose t heir shape at that distance.
Signals in GT&E's system, however, can travel 35 kilometers before they begin to weaken. Utilizing optical fibers recently developed by Corning Glass Works, the pulses in the new system are 1300 nanometers in length, still in the infrared spectrum, but less susceptible to absorption by their glass medium.
The first test link of the system is currently carrying phone calls between two switching centers of the Hawaiian Telephone Company located in Mililani and Pearl City on the island of Oahu (see map below), a distance of 32.4 kilometers.
The fibers themselves are encased in 3/8-inch-diameter cable manufactured by Siecor Optical
Cable of Hickory, North Carolina. In the Hawaiian system, the cable contains six of the Corning
fibers, each nearly I l-kilometers long. The six fibers are spliced into groups of three to form two
32.4-kilometer lengths that are looped back and forth three times between the switching centers. This arrangement enabled engineers to verify the system's ability to carry signals the entire distance without using pulse-regenerators.
According to Bernard Hill, vice- president of network engineering and construction for Hawaiian Telephone, the reduction in the need to install regenerators "will result in lower purchase and installation costs for optical telephone systems. "
"We expect that reduced equipment requirements will also result in a commensurate drop in the amount of maintenance required to keep the systems running at peak efficiency," Hill added. "In addition, the use of less equipment will help improve the overall reliability of such systems -- a benefit to customers as well as to the company."
(Image Omitted: Map of the island of Oahu, Hawaii, showing the proposed and completed sections of the Hawaiian Telephone C...