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Scalable and robust beam shaping using apodized fish-bone grating couplers



Chad Ropp, Dhriti Maurya, Alexander Yulaev, Daron Westly, Gregory Simelgor, Vladimir Aksyuk


Efficient power coupling between guided and free-space optical modes requires precision spatial mode matching with apodized Bragg gratings. Yet, grating apodizations are often limited by the minimum feature size realizable by the fabrication approach, especially at shorter wavelengths and for large area grating couplers. Here, we demonstrate a fish-bone grating coupler design for precision beam shaping and generation of millimeter-scale beams at visible wavelengths. Our design decouples the minimum structural feature size from the minimum achievable optical scattering strength, allowing smooth turn-on and continuous control of the emission. It is compatible with photolithography and has reduced sensitivity to both the resolution and the variability of the fabrication approach compared to subwavelength metagratings.
Optics Express


metagratings, PIC, photonic integrated circuit, beam projection, extreme mode converter


Ropp, C. , Maurya, D. , Yulaev, A. , Westly, D. , Simelgor, G. and Aksyuk, V. (2023), Scalable and robust beam shaping using apodized fish-bone grating couplers, Optics Express, [online],, (Accessed March 1, 2024)
Created November 20, 2023, Updated November 30, 2023