A new low-loss structure of abrupt bends in dielectric waveguides

In the proposed low-loss structure, a region whose refractive index is altered for reducing bending losses becomes much smaller. The beam propagation method is used to evaluate the loss of the modified corner bend proposed here. The validity of the results is confirmed in some cases through a comparison with those of a combination of the finite-element and boundary-element methods. Also, it is shown that the propagation characteristics of the proposed structure can be easily explained by using Snell's law.>