Fig. 9: Examples of inter-chip grating couplers.
From: Advances in waveguide to waveguide couplers for 3D integrated photonic packaging
a, b Grating-to-grating couplers using In bump self-alignment (reprinted with permission from ref. 101 ©Optical Society of America). c, d L-shaped grating for topological unidirectional resonance with inter-chip wavelength response102 (©2024 H. Wang et al., licensed under CC BY 4.0). In (e), SOI to Si3N4 intra-chip grating couplers using top and bottom reflectors are shown (reprinted with permission from ref. 126 ©Optical Society of America)
