A 4×212 Gbps 3.34pJ/bit Electronic-Photonic Co-Designed Transmitter Chipset in 0.18-um SiGe BiCMOS and 90nm Silicon Photonics

A 4×212 Gbps, 3.34 pJ/bit PAM-4 optical transmitter chipset for Linear Pluaggable Optics (LPO) applications is presented, featuring a co-designed architecture with a 57 GHz E/O bandwidth and a 20 dB gain control range. The proposed distributed driver consists of two Distributed Variable Gain Amplifier (DVGA) stages and one Distributed Amplifier (DA) output stage, achieving an E/E bandwidth larger than 67 GHz and 3Vppd for 212Gbps PAM-4 operation. Distributed Equlization technique is used for bandwidth extension while maintaining low group delay variation. Broadband output matching up to 60 Ω is realized through co-design of the DA output stage with a substrate-undercut Silicon Photonics Mach-Zehnder modulator (SiPh MZM). The integrated optical transmitter chipset achieves 212 Gbps PAM-4 operation with clear eye openings, an extinction ratio (ER) of 3.62 dB, and a TDECQ of 3.69 dB.