Co-packaged Optics on Glass Substrates for 102.4 Tb/s Data Center Switches

Next generation data centers are challenged with the task of delivering increased bandwidth and data rates at manageable power consumption. Co-packaged optics offer a path forward by enabling significant power reduction when electronic and photonic chiplets are locally mounted on a packaging substrate. In this paper, we discuss a glass substrate solution where both optical and electrical connectivity can be fabricated using ion-exchange (IOX) waveguides embedded into the glass and low-loss electrical routing. Design aspects are discussed to support 102.4 Tb/s data center switch applications. Signal transmission between the ASIC and PIC is completed with a total of 5 metal layers utilizing fine-line signal routing separated by ground planes. Through glass vias (TGVs) provide both power delivery for the mounted components and data management connectivity. Low-loss evanescent coupling occurs between the waveguides embedded in the glass substrate and photonic chips with high-density silicon nitride optical IOs. This design enables low-cost assembly methods involving the pick and place alignment of optical components and offers connectivity with low-profile mechanical transfer (MT) ferrule based fiber connectors.