CONTROL OF SCATTERING IN OPTICAL FIBER BY FIBER TWIST

Subject of Study. The paper deals with possibility of interference pattern control for light scattering in an optical fiber by variation of its space geometry. This paper considers the optical vortices propagating in a quartz fiber with periodic inhomogeneous inserts. Method.The experimental installation includes: an optical fiber, a laser, collecting lens and LiNbO3-modulator with voltage varying across its crystal according to predetermined spacing. The radiation was recorded with Nikon COOLPIX S32camera. We showed the possibility of distribution changing for light scattering intensity at its output by changing of piling geometry on the example of radial, triangular and random piling of a fiber. Main Results. We studied experimentally the evolution of the interference pattern for light interacting with optical inhomogeneities of the optical fiber in case of the light polarization alteration in proximity to the input end of a fiber. With the use of the frame analysis the time representations were obtained for the interference patterns in case of the radial, triangular and random piling of an optical fiber. The dependence of pattern formation time on the piling parameters was calculated. Regular optical fields and speckles were registered within this work. The main properties of those interference patterns were determined. It was found that for all polarizations the main properties of those interference patterns are preserved during the propagation of the laser beam in a twist fiber. Optical vortices were identified. The main circumstance of  this phenomenon identification was the light circulation.Practical Relevance.The obtained results can find application in optical telecommunication elements and in the fabrication of optical sensors.