  Efficient power coupling between on-chip guided and free-space optical modes
requires precision spatial mode matching with apodized grating couplers. Yet,
grating apodizations are often limited by the minimum feature size of the
fabrication approach. This is especially challenging when small feature sizes
are required to fabricate gratings at short wavelengths or to achieve weakly
scattered light for large-area gratings. Here, we demonstrate a fish-bone
grating coupler for precision beam shaping and the generation of
millimeter-scale beams at 461 nm wavelength. Our design decouples the minimum
feature size from the minimum achievable optical scattering strength, allowing
smooth turn-on and continuous control of the emission. Our approach is
compatible with commercial foundry photolithography and has reduced sensitivity
to both the resolution and the variability of the fabrication approach compared
to subwavelength meta-gratings, which often require electron beam lithography.
