Generation of OAM and Comparative Analysis of Generation Methods Related to Polarization Dependency

Optical fibers can carry various modal forms, including vector modes, linear polarization (LP) modes, orbital angular momentum (OAM) modes, and so on. We have investigated the structure of OAMs in optical fiber. We have simulated OAM modes, made a comparative analysis followed by a rigorous critique of the methods of shaping the orbital angular momentum beams related to polarization dependency. This analysis and criticism were made for the techniques using optical solids (cylindrical lenses, spiral phase plate, ...) and those generating the OAM in a fiber or fiber grating in helical form. The results showed that our method used to simulate OAM and those used for shaping in optical solids are considerably limited by polarization and hence applications of OAMs. On the other hand, the methods using a fiber or fiber grating in helical form leave a wide range of maneuver related to the polarization thus a greater application.