Initially based in Enfield, North London, and moved to Harlow Essex in 1959.
It is now recognised as the birthplace of optical fibre communications, for it is here that Sir Charles K. Kao, George Hockham and others pioneered the use of single-mode optical fibre made from low loss glass.
In 2009 Charles Kao was awarded the 2009 Nobel Prize in Physics, for pioneering optical fibre communication.
Another famous name associated with STL is Alec Reeves, previously famous for inventing pulse-code modulation while working at the Paris labs of the parent company ITT in 1938, and for his invention of the wartime bomber navigation system OBOE.
Since the collapse of Nortel, the site has been redeveloped into a new high-technology business development called KAOPARK.