Light coupling by a vortex lens into graded index fiber

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