40 Gbit/s AlGaAs/GaAs HBT 4:1 multiplexer IC

An experimental high speed 4:1 multiplexer integrated circuit capable of handling four simultaneous data channels without external delay lines is presented. The experimental circuit features an inherently fast two-stage configuration, with operation up to 40 Gbit/s demonstrated in an advanced AlGaAs/GaAs heterojunction bipolar technology. The system clock frequency is half the bit rate with only one additional self-generated internal clock necessary. A unique circuit topology has been chosen, which acquires, delays, regenerates, and retimes the incoming data. >