Dispersion-based all photonic crystals polarization beam splitter

We present the design and simulation of an ultra-compact high-efficient polarization beam splitter (PBS) based on the material engineering by combining photonic crystal dispersion properties and photonic band gap in this Letter. The PBS consists of two periodic structures: a polarization-independent self-collimation (PIS) structure and a splitting region. The PIS structure served as a virtual wave-guide in which the TE- and TM-polarized light can diffractionless propagate simultaneously; the splitting structure can be used to reflect TE-polarized light because it is within the photonic band gap, but TM-polarized light is transmitted across the splitting structure because it lies in the photonic band. The splitting properties of the PBS have been numerically studied using the finite difference time domain (FDTD) method. It has been shown a 90 degrees separating angle and efficiency of more than 85% for TE- and TM-polarized light over a wide frequency range 0.268-0.278(c/a) can be obtained. The size of PBS is only 9.0 mu m x 9.0 mu m at optical communication wavelength gamma = 1.55 mu m. These features of the proposed PBS make it a promising candidate in optical communication application. (C) 2007 Elsevier B.V. All rights reserved.