Photonics Research, Volume. 11, Issue 9, 1570(2023)
Optical leaky fin waveguide for long-range optical antennas on high-index contrast photonic circuit platforms
Fig. 1. 3D concept drawing of the proposed antenna structure. A vertical fin on top of a rectangular waveguide can couple the light upward depending on the position of this fin. The radiation strength is proportional to the asymmetry of the structure, defined by the offset of the fin from the center position of the waveguide core. The fin has a strong uniform grating on top to couple the light from the fin to free space, but this grating remains constant (no apodization) throughout the entire antenna design. The core layer tapers underneath the fin structure to maintain the propagation constant of the optical mode, required for emitting a Gaussian beam with a flat phase front. The simulations in this work are carried out with SiN as core and fin material, but the principle also works for Si platforms.
Fig. 2. (a) Conceptual illustration of a solid-state LiDAR system integrated on a chip surface. An integrated 1D OPA with dispersive antennas is used in combination with a tunable laser to limit the number of input waveguides and phase shifters to
Fig. 3. (a) Illustration of an integrated 1D OPA with dispersive antennas on the surface of a chip, consisting of a splitter tree, an array of electro-optic phase shifters connected to an emitting surface, which consists of a dense array of long (in the
Fig. 4. Illustration of the film mode matching modeling configuration of the vertical leaking structure. The top and bottom boundary condition is implemented as a transparent boundary condition (TBC), while the sides are implemented as perfect electric conductors (PECs). The structure is analyzed for different values of the waveguide core width
Fig. 5. Radiation strength
Fig. 6. Imaginary part of longitudinal field component
Fig. 7. Values of the partial derivatives from the spline interpolation used to create Fig.
Fig. 8. Corresponding
Fig. 9. Discretization of the antenna in segments to calculate required
Fig. 10. (a) Target Gaussian power profile (
Fig. 11. (a) Fitted polynomial
Fig. 12. (a) Resulting tapering function
Fig. 13. Top view of an array of the proposed antenna geometry, which now replaces the fabrication sensitive gratings used in Figs.
Fig. 14. (a) Top view of a 3D simulation result of the antenna design (
Fig. 15. (a) Calculated far field at
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Lukas Van Iseghem, Wim Bogaerts. Optical leaky fin waveguide for long-range optical antennas on high-index contrast photonic circuit platforms[J]. Photonics Research, 2023, 11(9): 1570
Category: Integrated Optics
Received: Mar. 20, 2023
Accepted: Jul. 3, 2023
Published Online: Aug. 28, 2023
The Author Email: Lukas Van Iseghem (lukas.vaniseghem@ugent.be)