11 Gbit/s multiplexer and demultiplexer using 0.15 mu m GaAs MESFETs

An ultra-high-speed 2-bit multiplexer (MUX) and demultiplexer (DEMUX) have been developed for ultra-high-speed optical transmission systems. A retiming D-type flip-flop (DFF), essential for transmission systems, was implemented at the MUX output stage. The measured system, consisting of MUX and DEMUX, operated at up to 11.2 Gbit/s. This is the fastest speed ever reported for a MUX with retiming DFF and DEMUX system. The ICs were realised by a newly designed circuit construction and 0.15 μm gate-length MESFETs with a cutoff frequency of 65 GHz.