Abstract: An improved optical printing head is described including a linear array of light sources, and a lens array comprised of graded index optical fibers arranged in a hexagonal close-packed array, there being at least three rows of individual fiber lenses. The linear array of light sources is aligned with, and parallel to, lines of symmetry of the graded index lens array, where the lines of symmetry are defined as lines along said graded index lens array which will transmit a line of light incident thereon with a minimum deviation in the intensity of light transmitted through the lens array. A photosensitive surface on a rotating drum is provided onto which light images from the optical printhead are incident. The print head can be used in optical printing machines.

Abstract: A semiconductor laser and optical waveguide are coupled together along a common optical axis and bounded at remote ends with reflective surfaces to form an optical resonant cavity. A periodic grating formed in a side surface of the optical waveguide directs some radiant energy out of the cavity in a direction not parallel with the common optical axis.