Microbending losses of doubly clad (W-type) optical fibers.

The microbending of optical fibers causes some additional transmission losses. In this paper, the theoretical and experimental results on the microbending characteristics for doubly clad (W-type) fibers are described. A simple approximation in which W-type fibers are considered as equivalent singly clad fibers is employed to calculate the additional losses due to microbending. It is shown that the additional losses of W-type fibers depend on the optical wavelength. Further, it is shown that the structural imperfections of the guide can be also considered a kind of microbending which affects the spectral loss characteristics of W-type fibers.