Abstract: Technologies for beam expansion and collimation for photonic integrated circuits (PICs) are disclosed. In one embodiment, an ancillary die is bonded to a PIC die. Vertical couplers in the PIC die direct light from waveguides to flat mirrors on a top side of the ancillary die. The flat mirrors reflect the light towards curved mirrors defined in the bottom surface of the ancillary die. The curved mirrors collimate the light from the waveguides. In another embodiment, a cavity is formed in a PIC die, and curved mirrors are formed in the cavity. Light beams from waveguides in the PIC die are directed to the curved mirrors, which collimate the light beams.

Abstract: Technologies for silicon diffraction gratings are disclosed. In some embodiments, grating lines of the diffraction gratings may have several sub-lines that make up each grating line of the diffraction grating. The sub-lines may be sub-wavelength features. In some embodiments, several silicon diffraction gratings may be made from a wafer, such as a wafer with a diameter of 300 millimeters. The wafer may be etched precisely across the entire wafer, leading to a high yield of the diffraction gratings.