An InGaP-HBT IC Chipset for 40-Gbps Optical-transmission Systems on the Basis of a Microwave-circuit Design Scheme

An InGaP-HBT IC chipset for 40-Gbps optical-transmission systems was developed on the basis of a microwave-circuit design schemedesign techniques, circuit configurations, and concepts. A distributed amplifier achieved ¿l50-GHz bandwidth and ¿164-GHz gain-bandwidth product, which are state-of-the-art values for GaAs-HBT-based baseband distributed amplifiers. A compact 40-GHz analog phase shifter with small insertion-loss variation, and 20-GHz/40-GHz clock amplifiers with very low power consumption (about 10 mW) were also realized. Moreover, a new approachinserting impedance-transformer circuits-to enable `impedance matching´ in high-speed digital ICs was successfully applied to a 40-Gbps decision circuit to prevent unwanted gain peaking and jitter increase caused by transmission lines without sacrificing chip size.