Application of dual-structure grating for equal three-channel splitting in reflection.

A new three-channel beam splitter with dual-structure is described in this paper. Through numerical calculation by finite element method (FEM), with an incident wavelength of 1550 nm, such the dual-structure grating can be obtained with diffraction efficiencies of more than 32% in the ± 1st and 0th order for transverse magnetic (TM) polarization and more than 31% for transverse electric (TE) polarization. The effect of period, duty cycle, incident angle and wavelength on the diffraction efficiency are also presented in this paper. Compared with other three-channel gratings, the proposed grating has wider incident wavelength bandwidth and satisfying performance. [ABSTRACT FROM AUTHOR]