We report a photonic crystal fiber with a depressed-index core doped with fluorine. The effective index of the cladding matches that of the core at an antiguiding wavelength, below which the fiber does not guide light at all.
© 2001 Optical Society of America
B. J. Mangan, J. Arriaga, T. A. Birks, J. C. Knight, and P. St. J. Russell, "Fundamental-mode cutoff in a photonic crystal fiber with a depressed-index core," Opt. Lett. 26, 1469-1471 (2001)