Hybrid integrated optical receivers for high-speed data transmission

Flip-chip-mounting of integrated circuits has been shown as an effective way to connect integrated circuits with substrates providing highest bandwidths. This technique also has been used to connect chips directly without causing significant parasitics. In this paper, hybrid integrated photo receivers with high bandwidth for fiber-optic data transmission will be discussed. Several photo receivers with bandwidths of more than 60 GHz have been fabricated by combining photodiodes and amplifiers, which have been optimised in separated wafer runs. Key features of this type of photo receivers are a wave guide photodiode with a high responsivity (0.8 A/W) and a travelling wave amplifier with low input impedance as well as high amplification to a 50 ohm output termination up to 65 GHz. Further improvement of bandwidth is expected by using metamorphic HEMTs instead of pseudomorphic ones in the amplifier.