40-Gb/s wide-band MMIC pHEMT modulator driver amplifiers designed with the real frequency technique

With the use GaAs pseudomorphic high electron-mobility transistor technology, the bandwidth performances of Cherry-Hooper driver amplifiers need to be improved. To fulfill these requirements, we propose an original driver circuit topology dedicated to 40-Gb/s optical communication systems. To flatten the transducer gain response of the circuit, passive networks have been added in the design. These networks have been optimized by means of the real frequency technique (RFT). A modified procedure of the classical RFT is introduced to perform the optimization in the presence of an overall resistive feedback.