A 32 Gb/s/λ 256Gb/S/Fiber Half-Rate Bandpass-Filtered Clock-Forwarding DWDM Optical Link in a 3D-Stacked 7nm EIC/65nm PIC Technology

We present a $32 \text{Gb} / \mathrm{s} / \lambda$ dense wavelength division multiplexing bandpass-filtered clockforwarding link featuring nine 200 GHz - spaced wavelengths (8 for data and 1 for clk). Fabricated in a 3D-stacked technology with an electronic IC in a 7 nm process and a photonic IC in a 65 nm SiPh process, our implementation achieves a throughput of $256 \text{Gb} / \mathrm{s} /$ fiber, delivering an energy efficiency of approximately $2.78 \text{pJ} / \mathrm{b}$ and an area efficiency of $1.33 \text{Tbps} / \text{mm}^{2}$-while maintaining 0.46 UI wide eye openings at $<1 \mathrm{E}-11 \text{BER}$.