132 GBaud PAM4 IM/DD Silicon Receiver Subassembly Realized by Stacking Technology

Stacking technology, such as direct bonding is a way forward for high speed photonic devices. In this work, we present silicon direct detection subassembly realized by direct aluminum – aluminum bonding of 200 mm wafers. The receiver features a BiCMOS transimpedance amplifier (TIA), germanium waveguide-integrated photodiodes for C- and O-band application and single-polarization (TE) grating couplers. An opto-electrical bandwidth of 84 GHz was measured. The total power consumption is 385 mW at a footprint of approximately 2.9 mm². Amplifier free, time domain measurements show open eyes up to 132 GBaud 4-level pulse-amplitude-modulation (PAM4) signal at 1300 nm. An efficiency of 1.46 pJ/bit was achieved.