A time division multiplexer IC for bit rates up to about 2 Gbits/s

A bipolar 4:1 time-division multiplexer IC developed for a planned 1.12 Gbit/s optical communication system is presented. Without resorting to sophisticated technology, the high speed was achieved by modification of well-known circuit concepts and by careful circuit optimization. With a current-switch output, reliable operation was measured to over 2 Gbit/s compared to over 1.5 Gbit/s if emitter-follower outputs are used. The experimental results agree very well with the simulation predictions.