Skew modes in specialty fibers with step-index profile

In step-index multimode-fibers, controlled excitation conditions are essential to achieve optimized transmission properties and control the output beam profile. Especially with lasers as a light-source, selective methods of mode excitation can be used easily. So far, fiber properties have been specified using meridional rays (modes), as proposed with the inverse far-field method. In addition to these meridional rays in step-index fibers, high-order skew rays can be selectively excited. Especially with excitation angles higher than the numerical aperture of the fiber, these skew rays can propagate with interesting properties. Based on these extreme test conditions, the core-cladding interface of large-core step-index fibers can be more efficiently controlled.