36 GHz bandwidth optoelectronic integrated circuit with flip-chip-assembled InP HBT/evanescently coupled photodiode

An optoelectronic integrated circuit (OEIC) with flip-chip technology for 1.55-µm wavelength application is demonstrated. The presented flip-chip OEIC comprises an InP chip and the carrier substrate. The InP chip consists of an evanescently coupled photodiode (ECPD), an InP/InGaAs heterojunction bipolar transistor (HBT) and bonding pads. The semi-insulating GaAs carrier consists of a coplanar waveguide, bias resistances, interconnects and pads (DC, RF and bonding pads). The flip-chip technology is used to reduce InP chip size and thus save cost. The fabricated ECPD exhibits a responsivity of 0.3 A/W and an f−3 dB of 30 GHz. The OEIC demonstrates an f−3 dB of 36 GHz with a transimpedance gain of 32 dB Ω. This is the first ECPD/HBT with flip-chip technology ever reported for OEIC.