A 50-MHZ-55-GHZ MULTIDECADE INP-BASED HBT DISTRIBUTED-AMPLIFIER

This letter reports on a 50-MHz-55-GHz multidecade bandwidth InP-based heterojunction bipolar transistor (HBT) MMIC distributed amplifier (D A) which achieves the widest bandwidth and highest frequency of operat ion so far demonstrated for a bipolar amplifier, The HBT MMIC DA was f abricated using a high-speed 1-mu m InAlAs/InGaAs-InP HBT base-undercu t technology with peak f(T)'s and f(max)'s Of 80 and 200 GHz, respecti vely, in order to obtain broad-band gain, Key to this work is the succ essful employment of HBT active load terminations used on both the inp ut and output DA transmission lines in order to extend the low-frequen cy gain performance down to baseband, With only 82 mW of de power cons umption, the amplifier obtains measured gains of 7.6 dB at 50 MHz, 5.7 dB at 30 GHz, 5.8 dB at 50 GHz, and 3.1 dB at 55 GHz. Simulations of a monolithically integrated InGaAs p-i-n photodetector predicts a base band 47-GHz photoreceiver response with an effective transimpedance of 38-dB Omega. The baseband millimeter-wave capability of the InP-based HBT DA and its compatibility with InGaAs photodetectors makes this te chnology attractive for future generation (>40 Gb/s) high-data-rate li ght-wave applications.