Abstract
We present a numerical computation technique on analyzing Bragg diffractions by superimposed transmission phase gratings. It can account for diffractions by any number of superimposed gratings with symmetric and asymmetric diffraction geometries. The angular and wavelength selectivity curves are shown to be still (sinc) exp 2 functional dependent in the examples provided. The selectivity bandwidth on one diffraction angle is found to depend on other superimposed diffraction gratings selected. The simple computation technique should be suitable for design engineers to establish grating index combinations prior to experimental implementation of optical beam splitting components. (Author)