Design and Realization of Multi-Channel and High-Bandwidth 2.5D Transmitter Integrated With Silicon Photonic MZM

Recently, the interconnection bandwidth of the data center is rapidly increasing. To satisfy the requirement for the high-performance data center, a 4-channel 2.5D silicon photonic transmitter is proposed and the packaging structure could increase the high-density scalability of the architecture for 1.6T/3.2T co-packaging optics (CPO) module. The electrical driver and silicon photonic Mach-Zehnder modulator (MZM) are mounted to the silicon interposer by the micro-bumps. Meanwhile, the silicon interposer is mounted to the low temperature co-fired ceramic by the solder balls. The 2.5D transmitter is assembled to the motherboard by the high-speed ball grid array (BGA) connector to make it convenient to be replaced. The electrical optimization is implemented to make the insertion loss of the whole passive link within −1.55 dB under 40 GHz, which ensures the transmitter with the socket transmit the clear simulated eye diagram at 64 Gbps PAM4 rate per channel. Moreover, the thermal evaluation is performed, which includes the heat- dissipation evaluation and the thermal-induced impact on the edge light coupling. Finally, the substrates in the 2.5D transmitter are fabricated and the transmitter is realized by the improved assembly method. By the verification of the measurement, the 2.5D transmitter we proposed could work at 64 Gbps PAM4 signal transmission rate per channel with the 6pJ/bit power consumption. Regardless of the bandwidth of the electronic integrated circuit (EIC)/MZM and the BGA connector, based on the simulation electrical bandwidth, it is potential for realizing 100 Gbps PAM4 signal transmission.