A 28 GHz HPT/HBT monolithically integrated photoreceiver for hybrid fibre radio distribution systems

High-speed, long-wavelength InP/InGaAs MMIC photoreceiver based on an HPT/HBT shared layer integration scheme has been designed, fabricated and characterised. The performance of individual devices and integrated circuit was investigated through detailed CAD-based analysis and characterisation. The bipolar heterojunction phototransistor (HPT), with the same HBT layer structure, exhibited a DC responsivity of 0.25 A/W and an optical gain cut-off frequency of 70 GHz at λ=1550 nm. The fabricated two stage cascode narrow band amplifier with an HPT and three HBT´s demonstrated a transimpedance gain of 50 dBΩ and a -3 dB bandwidth of 4 GHz at the frequency of 28 GHz. A system evaluation of the MMIC photoreceiver was also realised using a subcarrier at 27.875 GHz modulated with a 25 Mb/s 16 QAM signal, and a BER of 10^-9 for a C/N of 24.3 dB was achieved