Théorie de la propagation dans les fibres multimodales déformées aléatoirement. II. Application aux fibres à saut d'indice

In the present paper, the optical ray theory in paraxial approximation is applied to multimode graded-index optical fibers with random axial microbends. The theory is rigorous within the framework of the WKB method. An attempt is made to clarify as far as possible the case of an optical fiber free of losses, subjected to microscopically correlated microbends. The coefficients of the diffusion equation are calculated analytically. An exact solution of this equation is obtained for the fundamental statistical mode.