Development of a DMILL radhard multiplexer for the ATLAS Glink optical link and radiation test with a custom Bit ERror Tester

A high speed digital optical data link has been developed for the front−end readout of the ATLAS electromagnetic calorimeter. It is based on a commercial serialiser commonly known as Glink, and a vertical cavity surface emitting laser. To be compatible with the data interface requirements, the Glink must be coupled to a radhard multiplexer that has been designed in DMILL technology to reduce the impact of neutron and gamma radiation on the link performance. This multiplexer features a very severe timing constraints related both to the Front−End Board output data and the Glink control and input signals. The full link has been successfully neutron and proton radiation tested by means of a custom Bit ERror Tester.