We extensively study the propagation features of higher-order modes in a photonic crystal fiber (PCF). Our analysis is based on a full-vector modal technique specially adapted to accurately describe light propagation in PCF’s. Unlike conventional fibers, PCF’s exhibit a somewhat unusual mechanism for the generation of higher-order modes. Accordingly, PCF’s are characterized by the constancy of the number of modes below a wavelength threshold. An explicit verification of this property is given through a complete analysis of the dispersion relations of higher-order modes in terms of the structural parameters of this kind of fiber. The transverse irradiance distributions for some of these higher-order modes are also presented, showing an excellent agreement with recent experimental measurements. In the same way, the full-vector nature of our approach allows us to analyze the rich polarization structure of the PCF mode spectrum.
© 2000 Optical Society of America
(060.2270) Fiber optics and optical communications : Fiber characterization
(060.2280) Fiber optics and optical communications : Fiber design and fabrication
(060.2430) Fiber optics and optical communications : Fibers, single-mode
Albert Ferrando, Enrique Silvestre, Juan José Miret, Pedro Andrés, and Miguel V. Andrés, "Vector description of higher-order modes in photonic crystal fibers," J. Opt. Soc. Am. A 17, 1333-1340 (2000)