Can we see the future from here?

After the Second World War, it was clear that the telecommunications infrastructure of many countries needed an upgrade. The digital computer had been invented, and was emerging from the lab into the economy. In the USA, the giant early warning and control system, SAGE (Semi-Automated Ground Environment) was being built to cope with the threat of nuclear war, and needed systems and sensors to be connected across the country. The old copper cables of the telephone and telegraph systems were not up to the job.

Fortunately, experts, researchers and engineers had a solution: they would use light to transmit information rather than pushing electrons through copper. However, they did not start with the flexible, glass optical fibres that we are familiar with today: they believed that glass could not be manufactured with sufficient transparency to carry light over long distances and that, even if it could, the photons would escape at the bends.