Spin-orbit polarization effects in isotropic multimode fibres

The propagation of an electromagnetic wave in a locally isotropic but smoothly inhomogeneous medium is considered. Both geometric optical and wave optical approaches are used to account for the interaction between propagation and polarization, i.e. spin-orbit interaction of the photon. Starting with the recently derived equations the authors calculate the angular shift of a ray and of an interference pattern which arises as a consequence of the circularity sigma of polarization. The results obtained prove that both the lateral shift of the ray varies as sigma mod Del lambda mod (optical ping-pong effect) and Rytov-Berry-Chiao geometric rotation of polarization are manifestations of the spin-orbit interaction of a photon in an inhomogeneous medium.