Light coupling by a vortex lens into graded index fiber

This paper reports a novel launch scheme for coupling light into the skew rays of a graded index fiber. This is accomplished by utilizing a diffractive optical element in conjunction with a single mode fiber to mode match a graded index fiber. Results are used to confirm the fact that the element does improve the coupling into the skew rays of graded index fiber. This approach offers an alternative to existing methods based on tilting and angular offsets for the conditioned launch problem