It is represented the experimental results confirming the existence of the optical vortices after a low mode fiber end, while there are no free optical vortices propagating along the fiber itself. In this case the vortices are as a rule coupled. The vortex pairs is shown to arise at some distance from fiber output and then they disappear after passing through some space section. This distance revealed to be controlled by means of the fiber excitation way. Though the optical vortices are born (annihilated) in pairs, at the same distance a single vortex may appear separately in the observation field, displacing other vortices at the infinity. This happens due to the interference energy conversion from one vortex to an other.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.