Design, fabrication and connectorization of high-performance multimode glass waveguides for board-level optical interconnects

Fiber fly-overs are deployed for on-board optical interconnects in combination with on-board optical engines in different products such as high-performance switches for data centers. Polymer waveguides are a promising next step technology solution for integrated board-level optical connectivity to increase the interconnection density, their drawback is the high optical loss at key optical wavelengths around 1310 nm and 1550 nm where promising low-cost silicon photonic transceivers will operate. Glass waveguides fabricated by silver ion-exchange in glass panels have attracted significant interest as a cost-effective candidate due to their very low optical loss at key wavelengths and efficient coupling to optical fiber. The glass waveguide technology and board integration of glass waveguides have been demonstrated for multimode waveguides. Still, the performance of glass waveguides can be optimized by adjusting the refractive index profile for the specific requirements of complex circuits with small pitch, high-number of crossings and tight bends. Low insertion and cross-talk losses are important requirements. For off board communication a reliable connector solution is required for multi-fiber interconnection.