Microwave radios are being used extensively by Japanese electric power companies for the operation and maintenance of large complex power systems. Because of the congestion in radio frequency spectrum, however, power companies had just started to consider the coaxial cable laid alongside underground power cables as an alternative to radio when the optical fiber transmission became promissing. The optical fiber is found to be more attractive than the conventional coaxial cable when the added cost of shielding is taken into account, since expensive coaxial shielding is necessary to minimize the induction from power cables. Consequently, both The Tokyo and The Kansai Electric Power Companies are planning to introduce optical fiber systems in the late 1970's.
© 1977 Optical Society of AmericaPDF Article