Compact Broadband Edge Coupler Based on Trident Gratings for Silica Platform

This is the authors' abstract. We don't add key points for this paper.

The silica platform offers large-scale, low-cost fabrication for planar lightwave circuits (PLC). The broadband and compact fiber-to-chip edge coupler is essential for high performance PLC chips. Here, a silica trident gratings-based edge coupler is theoretically designed and experimentally demonstrated. By CMOS compatible fabrication, the prepared coupler presents the fiber-to-chip coupling loss of 0.95 and 0.93 dB/facet at the optical wavelength 1310 and 1550 nm, respectively. The coupling loss varies from 0.41 to 1.36 dB/facet over the wavelength range from 1264 to 1620 nm. Specifically, the edge coupler features the large alignment tolerance of± 3μm and± 3.5μm for a 1-dB penalty along directions of waveguide width and height, respectively. The small footprint of8.6~μm× 83.2~μm offers the coupler potentials in compact PLC applications.