A new type ultraflattened dispersion photonic crystal fiber with low confinement loss X. L. Tan, Y. F. Geng, Y. P. Zhang, H. Y. Zhang, P. Wang and J. Q. Yao Eur. Phys. J. Appl. Phys., 40 2 (2007) 175-179 Published online: 21 September 2007 DOI: 10.1051/epjap:2007134