US Patent 10203453 Facet optical coupler

Techniques for forming a facet optical coupler to couple light at an edge of silicon substrate are described. The facet optical coupler includes a silicon substrate, a layer of second material disposed on the silicon substrate and in direct contact with the edge of the silicon substrate, and an undercut region disposed between a portion of the silicon substrate and the layer of second material. The undercut region is offset from the edge to provide mechanical integrity of the facet optical coupler to improve production of photonic integrated circuits having the facet optical coupler from a wafer.