A photonic integrated device comprises a waveguide embedded in a photonic substrate. The waveguide has a waveguide radiation exit surface and the waveguide is optically connected to a two dimensional grating. The photonic integrated device also comprises a two dimensional grating having a plurality of curved elongate scattering elements. The two dimensional grating is adapted for diffracting radiation received from the waveguide toward a direction out of the photonic substrate and the curved elongate scattering elements are oriented with respect to the waveguide such that, for points of the scattering elements which can be irradiated by radiations stemming from the waveguide, normal lines to at least the curved elongate scattering element closest to the waveguide radiation exit surface do not substantially intersect with the waveguide radiation exit surface of the waveguide.