Digital-Preprocessed Analog-Multiplexed DAC for Ultra-high-speed Optical Transmission

Driven by the rapid increase in data traffic, demands for data rates of optical transmission systems keep growing. Since optical transmitters and receivers of today rely on advanced digital signal processors (DSPs), the bandwidths of digital-to-analog and analog-to-digital converters (DACs and ADCs) are the key factors to determine the data rates. We have devised a DAC subsystem with an analog bandwidth of up to 60 GHz using a digital preprocessor, two CMOS sub-DACs, and an analog multiplexer based on a InP HBT technology. In this talk, we show the principle of the signal syntheses and recent experimental results enabled by this technology.