50-Gb/s SiGe BiCMOS 4:1 multiplexer and 1:4 demultiplexer for serial communication systems

4 multiplexer and 1 demultiplexer ICs targeting SONET OC-768 applications are reported..The ICs have been implemented using a 120-GHz-fT 0.18-μm SiGe BiCMOS process. Both ICs have Been packaged to enable bit error rate testing by connecting their serial interfaces. Error-free operation has been achieved for both circuits at data rates Beyond 50 Gb/s. At a - 3.6-V supply voltage, the multiplexer and demultiplexer dissipate 410 and 430 mA, respectively. Switching behavior of the 4 : 1 multiplexer has also been checked up to 70 Gb/s.