Zegadlo K, Karpierz M. Analysis of a beam propagation in optical fiber structures with high step index. Photonics Lett. Pol. [Internet]. 2009 Dec. 31 [cited 2024 Jul. 22];1(4):pp. 175-177. Available from: http://photonics.pl/PLP/index.php/letters/article/view/1-59