Single-mode glass waveguide substrate for PIC packaging

Next generations of datacenter switches require co-packaging of optics and ASICs on the same substrate to reduce the interconnection length of electrical lines leading to higher bandwidth and power reduction. New optical connectivity solutions are needed for coupling of fiber arrays to silicon photonic transceiver chips. Low-loss, high-bandwidth, and high channel count are the key requirements for the fiber-to-chip interface. Evanescent coupling is a promising approach enabling a high-throughput and low-cost assembly. Low-loss single-mode waveguides integrated in a glass substrate with a propagation loss of 0.08 dB/cm and a fiber coupling loss of 0.3 dB can be evanescently coupled to silicon photonic waveguides. The waveguides are integrated in a glass substrate by silver ion-exchange. The paper introduces waveguide technology and evanescent coupling approach based on a non-linear silicon waveguide taper design leading to coupling loss of 0.25 dB.