GaAs distributed amplifiers with up to 350 GHz gain-bandwidth product for 40 Gb/s LiNbO/sub 3/ modulator drivers

In this paper, we report on two Distributed Amplifier (DA) concepts for 40 Gb/s modulator drivers. Both amplifiers are fabricated in a commercially available 150 nm GaAs power pHEMT technology. The first DA is a six stages design with capacitive division on the gate line. Gain and bandwidth of this amplifier equal to 13.2 dB and 41 GHz, respectively. The other DA consists of nine cascode stages, achieving 20.1 dB gain and a bandwidth of 34.5 GHz. Output power of the two amplifiers is higher than 21 dBm or 7 Vpp up to 20 GHz, which makes them suitable for driving lithium-niobate (LiNbO/sub 3/) modulators.