Fig. 13: Examples of waveguide-to-waveguide coupling utilizing optical wirebonds.
From: Advances in waveguide to waveguide couplers for 3D integrated photonic packaging
a, b Photonic wirebonds (PWBs)178 (reprinted with permission from ref. 178 ©Optical Society of America). In (a), the mechanism of TPP printing of PWBs for chip-to-chip coupling. In (b), an SEM image of one of the PWBs coupling SOI to SOI. c, d Direct optical wirebonds (DOWs) (reprinted with permission from ref. 179 ©Optica Publishing Group). In (c), the mechanism of printing the DOW for chip-to-chip coupling using a micro-machined glass nozzle. In (d), microscope images of the fabricated DOWs. In (e), a schematic view of SmartPrint technology including the graded index profile for the polymer waveguides and a cross sectional view of the IOX waveguides with polymer cross tapers (reprinted with permission from ref. 180 ©2022 IEEE). f, g 3D ULI waveguide couplers (reprinted with permission from ref. 163 ©2018 IEEE). In (f), a schematic of 3D ULI fabrication along with a zoomed in view of the end terminations for SiN-to-ULI waveguide coupling using adiabatic tapers. In (g), a cross section of ULI waveguides fabricated in commercially available eagle glass substrate and LPCVD oxide cladding with the measured optical mode profile. In (h), the SCRIBE technique is shown for forming free standing micro-optic devices in mesoporous silicon64 (©2020 Ocier et al., licensed under CC BY 4.0). In (i), a schematic of the flexible paralyne waveguide with mirror end facets for optical connections185 (©Reddy et al., licensed under CC BY 4.0)
