Demonstration of high waveguide bending efficiency (>90%) in a photonic-crystal slab at 1.5μm wavelengths

Using a two-dimensional (2D) photonic-crystal slab structure, we have demonstrated a strong 2D photonic band gap with the capability of fully controlling light in all three dimensions[1]. Our demonstration confirms the predictions [2] on the possibility of achieving 3D light control using 2D band gaps, with strong index guiding providing control in the third dimension, and raise the prospect of being able to realize novel photonic-crystal devices. Based on such slab structure with triangular lattice of holes, a 60-degree photonic-crystal waveguide bend is fabricated. The instrinsic bending efficiency (η) is measured within the photonic band gap. As high as 90% bending efficency is observed at some frequencies.