Photonic Chiplet Interconnection via 3D-Nanoprinted Interposer

Photonic integrated circuits utilize various waveguide materials, each excelling in specific metrics like efficient light emission, low propagation loss, high electro-optic efficiency, and potential for mass production. Inherent shortcomings in each platform push exploration of hybrid and heterogeneous integration, which demands specialized designs and extra fabrication processes for each material combination. Our work introduces a novel hybrid integration scheme employing a 3D-nanoprinted interposer for a photonic chiplet interconnection system. This method represents a generic solution that can readily couple between chips of any material system, with each fabricated on its own technology platform with no change in the established process flow for the individual chips. Mode-size engineering is enhanced by the off-chip parabolic micro-reflectors. The 3D-nanoprinted chip-coupling frame and fiber-guiding funnel enable low-loss, fully passive assembly with a fast-printing process achieving sub-micron accuracy. Mode-field-dimension conversion ratio of 5:2 from fiber to chip is demonstrated with <0.5dB excess loss on top of the 1.7dB inherent coupling loss, marking the largest mode size conversion using non-waveguided components. Additionally, our system demonstrates a 2.5dB die-to-die coupling loss between silicon and InP chips over a 140nm wavelength range (1480nm to 1620nm), showcasing the potential for extensive cross-platform integration by bridging different waveguide materials.