108-GHz-Bandwidth Compact InP-HBT Baseband Amplifier Module With Integrated DC-Block Functions

We designed and fabricated a compact and low-cost ultrabroadband amplifier module. The 3-dB-down-cutoff frequency (f3dB) of the module is 108 GHz with direct-current (dc) block functions. The module achieves an output 1 dB compression point (P1dB) of 7.6 dBm at 100 GHz. We also succeeded in validating the linear amplification of a broadband signal of 112-GBd pulse-amplitude-modulation four-level (PAM4). Adapting push-on-type connectors for the interface of the module, we could reduce its size, which is
$11.8\times 10\times4.3$
mm3, and cost. To the best of our knowledge, this is the first report on a compact baseband amplifier module that has a bandwidth of over 100 GHz with integrated dc-block functions.