One-to-three and T-shaped beam splitters based on self-collimating photonic crystals

In this paper, a one-to-three beam splitter and a T-shaped one-to-two beam splitter are proposed by introducing a V-shaped air gap into a self-collimating photonic crystal (PC). By adjusting the width of the introduced air gap to proper values, the incident beam can be divided into two or three sub-beams. The plane wave expansion method is employed to obtain the equifrequency contours and the band diagram of the PC. The splitting ratios between the sub-beams as a function of the width of the air gap are calculated by using the finite-difference time-domain method. Meanwhile, the field distributions of the light propagation in the structure are presented.