7.6 A 1.23pJ/b 2.5Gb/s Monolithically Integrated Optical Carrier-Injection Ring Modulator and All-Digital Driver Circuit in Commercial 45nm SOI

Integrated photonic interconnect technology presents a disruptive alternative to electrical I/O for many VLSI applications. Superior bandwidth-density and ener-gy-efficient operation can be realized through dense wavelength-division multi-plexing (DWDM) and lower transmission losses. There are two main paths towards an integrated platform. Hybrid/heterogeneous designs [1-3] enable each component to be custom-tailored, but suffer from large packaging para-sitics, increased manufacturing costs due to requisite process flows, and costly 3D integration or microbump packaging. Monolithic integration mitigates inte-gration overheads, but has not penetrated deeply-scaled technologies due to necessary process customizations [4]. The first monolithic integration of pho-tonic devices and electronic-photonic operation in sub-100 nm (45 nm SOI process with zero foundry changes) is demonstrated in [5]. This paper presents a monolithically integrated optical modulator with a new all-digital driver circuit in a commercial 45nm SOI process. The waveform-conditioning driver circuit enables the carrier-injection modulator to operate at 2.5Gb/s with an energy-cos