Communications: Electronics and optics, too: Solid-state lasers, optical waveguide, and digital techniques for TV broadcasting come on line

The important progress in communications and microwave hardware observed by Spectrum during 1975 consisted largely of refinements in existing equipment or new applications of proven techniques — including commercially available solid-state lasers and optical waveguides, a computer-controlled customer-premises private branch exchange, new channel assignments and equipment for mobile telephones, digital techniques as applied to commercial television broadcasting, and design refinements in microwave antennas for communications, radar, and satellite applications. However, there was at least one noteworthy exception to the emphasis on the practical. This was the “optical transistor,” the direct amplification of laser beam signals, described by Bell Laboratories' Samuel L. McCall during the annual meeting of the Optical Society of America held in Boston this past October. So far, the effect has been demonstrated only with extensive laboratory equipment.