In 1983, when this film was made, fiber optic cables were still in the research and development phase for underwater use. But satellite traffic at the time was stretched to capacity, so AT&T returned to the sea to lay communications lines that could handle much more traffic than the old copper coaxial cables. The lightwave undersea cables were a drastic improvement in connectivity. Here's a chart showing the growth of cable technology from 1956 - 91:
1956: 51 conversations simultaneously
1963: 138 conversations simultaneously
1970: 845 conversations simultaneously
1988: 36,000 conversations simultaneously
1991: 72,000 conversations simultaneously
The first transatlantic telephone cable to use fiber optics, or lightwave systems, was TAT-8, which went into operation in 1988. This film shows its development and testing.
This work caused a flurry of development and investment internationally in undersea fiber optic cabling in the years to follow. In fact, the peak of investment came in the two years between 1999 and 2001, when there was more than $22 billion invested in undersea fiber optics worldwide. Most cable-laying operations after 2007 have been in the Pacific region, due to the growing Asian markets.
Footage courtesy of AT&T Archives and History Center, Warren, NJ