Propagation of circularly polarized light along a curved trajectory

How the eigenfunction of an optical fiber is affected by a slight curvature at bends of the fiber without twisting is analyzed. The effect of a twisting of the ray trajectory in the case with curvature is examined theoretically by the geometric-optics approach. The results are used to analyze the problem of the turning of a meridional ray due to a circular polarization in a multimode optical fiber with a parabolic profile of the refractive index.