A GaAs distributed amplifier with an output voltage of 8.5 V/sub PP/ for 40 Gb/s modulators

摘要

In this paper, we report on a distributed amplifier (DA) with positive gain slope and 8.5 V/sub PP/ output voltage swing at 20 GHz. This makes the amplifier suitable for driving LiNbO/sub 3/ modulators. The amplifier consists of six cascode cells and is fabricated in a commercially available 150 nm GaAs power pHEMT technology. Gain equals to 9.8 dB at low frequencies and rises up to 12.8 dB at 38 GHz. This amplifier is then cascaded with a preamplifier. Losses at high frequencies due to cascading are compensated by the positive gain slope of the amplifier described here. The cascaded amplifiers exhibit a gain of 19.5 dB and a bandwidth of 38 GHz with a flat frequency response of /spl plusmn/0.6 dB up to 28 GHz.