A 2:1 time-division multiplexer is presented which operates up to 50 G
bit/s. This is the highest data rate ever achieved by an integrated ci
rcuit in any technology. The output voltage swing is 1 V peak-to-peak
at 40 Gbit/s and 0.6 V peak-to-peak at 50 Gbit/s (at 50 Omega on-chip
matching). The chips were fabricated in an advanced Si-bipolar technol
ogy (f(T) = 35 GHz) and mounted on a comparatively simple measuring so
cket.