Optical waveguide fan-out elements using dislocated gratings for both outcoupling and phase shifting

A novel scheme is proposed and experimentally demonstrated for the construction of an optical waveguide fan-out element. The device is composed of an array of rectangular elements, each containing a dislocated grating, on an optical waveguide. The functions of the gratings are twofold: outcoupling the guided wave and introducing phase shifts. Such a waveguide fan-out device has been fabricated on an AlGaAs-GaAs waveguide. The uniformity error and the diffraction efficiency were measured to be /spl sim/11% and /spl sim/60%, respectively.