Transmission characteristics of VAD multimode optical fibers.

The influence of convex striations of vapor phase axial deposition (VAD) optical fibers on transmission characteristics has been analyzed. These convex striations are inherent in optical fibers made by VAD and cause refractive-index fluctuations in both radial and axial directions. The phase of the sinusoidal fluctuations in the radial direction varies periodically along the fiber axis. Numerical analysis shows that bandwidth degradation due to sinusoidal fluctuations in the radial direction can be alleviated by a periodic phase variation in the axial direction.