Polarization-independent linear waveguides in 3D photonic crystals.

Using a symmetry-based approach, we have designed polarization-independent waveguides in a 3D photonic crystal. A comprehensive series of numerical experiments, involving the propagation of pulsed signals through long straight waveguide sections and sharp bends, quantitatively evaluates the bend-transmission coefficient over the entire bandwidth of the corresponding guided modes. High (approximately 95%) polarization-independent bend transmission is achieved within a certain frequency range.