A 3D-Integrated 56 Gb/s Silicon Photonic Transceiver with 5nm CMOS Electronics for Optical Compute Interconnects

This work presents a hybrid-integrated silicon photonic <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\text{SiPh})$</tex> transceiver suitable for realizing chiplet-based optical <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{I}/\mathrm{O}$</tex> in future <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{AI}/\text{ML}$</tex> ASIC packages. The transceiver die stack consist of two ICs: a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{SiP}\overline{\mathrm{h}}$</tex> IC (PIC) with compact, thermally stable electro-absorption modulators (EAMs), and a 5 nm CMOS electronic IC (EIC) with 56 Gb /s NRZ SerDes and optical interface circuits. A stacked CMOS EAM driver delivers 1.8 Vpp modulation voltage, achieving 3.5 dB extinction ratio. Transmit equalization and inductive peaking help accommodate sub-Nyquist RX analog front-end bandwidth, thereby reducing additive thermal noise from RX electronics. The complete 56 Gb <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$/\mathrm{s}$</tex> NRZ optical link consisting of the fiber-attached 3D SiPh transceiver and an external packaged light engine achieves BER <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$&lt; 10^{-9}$</tex> with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$&lt; -10.7\text{dBm}$</tex> RX OMA while dissipating 2.8 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{pJ}/\text{bit}$</tex>. The transceiver electronics consumes only 0.09 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{mm}^{\overline{2}}$</tex> area, delivering more than 600 Gb <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$/\mathrm{s}/\text{mm}^{2}$</tex> areal bandwidth density.