The radiation characteristics of waveguide diffractive doublets consisting of double gratings located on two surfaces of waveguide cladding film are modeled based on a singular perturbation method. We determine the conditions under which the presence of the upper grating does not affect the radiation characteristics of the waveguide diffractive doublet as a whole. This allows independent performance of the upper grating, which may be replaced by a general diffractive optical element, and of the lower grating as a waveguide grating coupler. The results obtained provide an alternative method for determining the thickness of cladding film in the waveguide diffractive doublets for guided-wave manipulation.
© 1998 Optical Society of America
(050.1970) Diffraction and gratings : Diffractive optics
(050.2770) Diffraction and gratings : Gratings
(060.1810) Fiber optics and optical communications : Buffers, couplers, routers, switches, and multiplexers
Tingdi Liao and Stephen Sheard, "Radiation Characteristics of Waveguide Diffractive Doublets," Appl. Opt. 37, 1776-1783 (1998)