diffraction gratings; integrated optics; optical beam splitters; optical couplers; fiber grating coupler structure; integrated 16-way power splitter; integrated grating coupler/power splitter; nonuniformity; on-chip optical power distribution; single grating coupler; total coupling efficiency; Arrayed waveguide gratings; Couplers; Gratings; Integrated optics; Nonlinear optics; Optical coupling;
