## 초록

A broadband amplifier for 40-Gb/s optical transmission systems was developed by using molecular-beam-epitaxy-based InGaAs/InP heterojunction bipolar transistor (HBT) technology. The developed InGaAs/InP HBTs showed a cut-off frequency ($\rm f_T$) of 129 GHz and a maximum oscillation frequency ($\rm f_{max}$) of 175 GHz. The design and the performance of an InGaAs/InP broadband amplifier for 40-Gb/s receiver applications are presented. The on-wafer developed broadband amplifier provides a bandwidth of 30.5 GHz and a gain of 19.2 dB. Packaged broadband amplifier modules were successfully fabricated. A 40-Gb/s data eye with a 403 m$\rm V_{pp}$ amplitude of the fabricated broadband amplifier module was achieved by using 40-Gb/s multiplexing voltage input signals.