Optical Design and Applications for Ion-Exchanged Glass Waveguide Circuits

Glass provides high dimensional stability and flatness, enabling high-throughput electronic assembly with high precision optical alignment for co-packaged optics (CPO) applications. Optical waveguides can be integrated in the glass core material by the thermal silver ion-exchange (IOX) process at temperatures around 350°C for fiber to chip connectivity. Currently available IOX glasses degrade due to ion mobility at operating conditions so we designed a new glass composition enabling waveguides to be stable over a lifetime of five years at an elevated temperature of 85°C or higher without performance degradation which could impact the integrity of the optical signal. The glass composition was optimized for thermal stability and low loss IOX waveguides were fabricated with propagation loss of only 0.034 dB/cm. Waveguide designs are studied and evaluated for waveguide crossings, high-density spacing, tight bends, high-optical power transmission, and polarization dependency. The waveguide technology is demonstrated for different applications including glass waveguide bridge for fiber to chip-coupling, multi-core fan-out, optical waveguide shuffle and an optical waveguide circuit for CPO with over 1024 waveguide interconnects.