Beam propagation modeling of arbitrarily bent waveguides

A numerical method for computing the wave fields in arbitrarily bent waveguides is developed based on a curvilinear coordinate system and the beam propagation method. Unlike earlier approaches based on the conformal mapping or the polar coordinate system, waveguides with arbitrary bends can be conveniently modeled. The new method is accurate for bends with any curvature, since it avoids the small curvature approximation.