I was at STL from 1962 – 1964 in the optical communication team and can be seen in your publicity photo with Murray Ramsay and Chris Dobson. The occasion was the successful demonstration of a GaAs diode laser fabricated by Dobson et al in January 1963 only weeks after the first reports from the USA. The picture (a staged publicity shot) shows the liquid nitrogen cryostat containing the laser along with the spectrometer and electronics rig that I assembled. I am standing by the chart recorder displaying the near infrared spectrum of the diode output showing how the broad band of spontaneous emission at low current suddenly and dramatically narrows and peaks as the input current is increased marking the transition to coherent laser light.
(Murray and Chris are pretending to twiddle knobs but were not actually involved in conducting the experiments. The success was celebrated with champagne upstairs with management).
I got to know Charlie Kao quite well – although he was not involved in the above experiments – his lab was further down the corridor on the ground floor south side of the building looking out on the ‘drainpipe’ rig. I remember a conversation with him when he asked me what I thought about the possibility of using glass as an optical communication waveguide. I had worked on the near infrared spectra of doped germanium for my PhD and knew that device quality germanium has to be purified to an extremely high level and consequently has very low optical absorption in the near infrared. This led me to suggest by way of analogy that the absorption in glass might be made very low if the impurities could be removed.

Bill Taylor
12/01/17