Low loss sharp photonic crystal waveguide bends

In this paper we study slot structures in the 120° photonic crystal waveguide (PCW) bends. We find that the transmission characteristics of the slotted PCW bend can be simply predicted by analyzing the corresponding straight PCW. According to our mode analysis for straight PCW, the slot structure blue shifts the stopband of the fundamental mode, while enhances the light confinement at slot side. The experiment shows good agreements with the simulation. Furthermore, a low bending loss in broad bandwidth has been obtained in the capsule-shaped slot PCW bend, which is very useful for broadband application.