The Services Electronics Research Laboratory (SERL) was established in 1945 at Harlow and Baldock, as the research department for contract valve development. They were a specialist material manufacturer in military electronics.

1945/50: SERL concentrated on Q-band magnetron (8.6 mm wavelength), Q-band Local oscillator, Z-band wide bandwidth TR and ATR cell and Ruggedised miniature vales for VT fuzes. In 1962, SERL begins work on ‘Optical Masers’, later Lasers, initially leading to the He-Ne ring laser proposed for inertial navigation systems. In 1964 SERL started work on the low-noise parametric amplifier, which became widely used in satellite communication and radar systems. The following year SERL begins work on photo-emitters that leads to the 1970s’ GaAs:CsO photocathodes for the later generation image intensifiers.

In 1976, SERL merges with RRE and SRDE and it was renamed Royal Signals and Radar Establishment (RSRE).