EPIC-BOE: An Electronic-Photonic Chiplet Integration Technology with IC Processes for Broadband Optical Engine Applications

Future GAI system demands more parallelism for performance with higher energy efficiency, high bandwidth density, and low latency than today's systems. We propose first full integration technology for Broadband Optical Engine (BOE) applications from fiber to CoWoS system by leveraging TSMC 3DFabric™ and IC processes forming compact CPO achieving GAI system PPA enhancement. It has high bandwidth coverage from 1260 to 1360 nm and high fiber-count that vertical coupler enjoys. Unlike the conventional broadband solution-edge coupler (EC), this solution is immune from beachfront warpage issue when we integrate 40 to 80 fibers per row. Innovative process flow realizes multiple row counts. SiN waveguide, fiber coupler, inter-layer-waveguide transitions, and polarization control devices are realized with IC process to achieve high performance with high energy efficiency. Low-Loss waveguide yields propagation loss of <0.01 dB/cm and 90-degree-bending-loss of <0.001 dB per turn. This IC process can leverage existing process control and inspection metrology. A novel SiN fiber coupler can achieve not only ultra-low coupling loss of 0.08 dB, but also withstand high input laser power of > 300 mW for 3 hours without degradation. Compact, large spacing inter-layer transition with 0.015dB loss is measured. Polarization control device PBSR, can be readily integrated in Fiber Array Unit (FAU) for saving PIC area, has extinction ratio of > 23 dB across 1260–1360 nm with loss < 0.3 dB for both TE and TM modes. The FAU system can then be made field serviceable. Despite the ever-increasing fiber count and their size mismatch with compact EIC-PIC structure, our innovative EPIC-BOE technology, made from IC processes with available inline test methodology, achieves high scalability for system PPA and high-volume manufacturability.