• A 32 Gb/s PAM-4 DFB laser driver in 28-nm CMOS achieves high linearity via a digital slicing architecture with three thermometer-coded main paths.
• An efficient-biased output stage reduces power consumption without sacrificing output node bandwidth, addressing parasitic capacitance issues.
• A two-tap linear and nonlinear FFE in the digital domain extends bandwidth and compensates for DFB laser dynamic nonlinearity, with low power and area overhead.
• Measured at 32 Gb/s PAM-4 with 40 mA bias and 20 mApp modulation, the driver consumes 372 mW, achieving an energy efficiency of 11.6 pJ/b.