120 GBd SiGe-Based 2:1 Analog Multiplexer Module for Ultra-Broadband Transmission Systems

A 2:1 analog multiplexer (AMUX) module based on a SiGe-HBT IC is presented. The AMUX module offers a 6-dB analog signal path bandwidth of 61 GHz. We show a 120 GBd 4-level pulse amplitude modulation (PAM) signal with the AMUX module fed by two CMOS-digital-to-analog converters (DACs), each with 19 GHz analog 3-dB bandwidth only, thus demonstrating high-baud-rate signal generation with bandwidth-limited CMOS DACs enabled by advanced digital signal processing.