Heterogeneous integration of a GaN-based photonic integrated circuit with an Si-based transimpedance amplifier

The heterogeneous integration of a GaN-based photonic integrated circuit (PIC) and an Si-based transimpedance amplifier (TIA) is demonstrated in this work. The mono-lithic GaN PIC, fabricated from a GaN-on-Si light-emitting diode (LED) wafer, comprises LEDs whose optical out-puts are coupled to photodetectors (PD) through suspended waveguides. The PIC chip is mounted onto a printed circuit board together with a TIA chip and two filter chip capac-itors, occupying a compact footprint. The components are interconnected directly using wire-bonds to minimize signal delays and attenuation. The integrated system achieves rise and fall times of 2.21 and 2.10 ns, respectively, a transmis-sion delay of 3.54 ns, and a bandwidth exceeding 390 MHz. Transmission of a pseudorandom binary sequence-3 (PRBS-3) signal across the integrated system is also demonstrated at the data transmission rate of 280 Mbit/s with a clearly resolved open eye diagram.(c) 2023 Optica Publishing Group