45 GHz transimpedance 32 dB limiting amplifier and 40 Gb/s 1:4 high-sensitivity demultiplexer with decision circuit using SiGe HBTs for 40 Gb/s optical receiver

A preamplifier with 45 GHz bandwidth and 50.2 dB/spl Omega/ transimpedance gain, a limiting amplifier with 32 dB gain and 49 GHz bandwidth, and a 40 Gb/s 1:4 high-sensitivity demultiplexer (HS-DEMUX) combined with a decision circuit are for use in a 40 Gb/s optical receiver. The bandwidth in the preamplifier and the maximum gain at 40 GHz in the limiting amplifier are the best reported for any semiconductor technology. The 1:4 HS-DEMUX uses bit-rotation for byte-synchronization.