Very high gain, high sensitivity, 40 GHz narrowbandphotoreceiver for clock recovery

A 40 GHz photoreceiver has been implemented by cascading on a single alumina substrate a fast side-illuminated AlGaInAs/InP pin photodiode, and three narrow-band amplifier chips, based on a 0.2 µm gate length GaAs pHEMT technology. The package was especially designed to suppress parasitic cavity-resonances. The photoreceiver current-gain is 57 dB, and the average input noise is < 30 pA/√Hz over the –3 dB bandwidth of 40.4 – 41.4 GHz. This is believed to be the highest photoreceiver gain ever reported in a single compact metal package at such a high frequency.