A low-power, radiation-hard gigabit serializer for use in the CMS electromagnetic calorimeter

Abstract

Abstract-An integrated fiber-optic bit serializer and VCSEL (Vertical Cavity Surface Emitting Laser) driver has been constructed in radiation-hard complementary heterostructure GaAs FET (CHFET) technology. The serializer, which converts 20 parallel inputs into a high-speed serial output, consumes 60 mW at nominal supply voltage when operating at the Large Hadron Collider (LHC) word rate of 40 MHz (0.8-GB/s serial rate). The integrated driver directly drives a VCSEL and provides 10-mA switched current and 5 mA of prebias. The complete digital optical link thus consumes 90 mW.

Light-to-light readout system of the CMS electromagnetic calorimeter

“…A first proof-of-principle version [10] was submitted in November 1997. This circuit consisted of a 20-bit serializer, converting 20 parallel inputs with a 40 MHz word rate into an 800 MB/s optical output stream.…”