Birefringence and large mode area analysis of segmented cladding index-guiding photonic crystal fibers

High birefringence and large mode area are the two paramount requirements of single-mode fibers to control polarization mode dispersion and nonlinear effects. We have investigated the birefringence, higher-order mode coupling loss of a fundamental mode (FM), and numerical aperture of index-guiding segmented cladding photonic crystal fibers in continuation to our previous analysis of the design for FM confinement and V parameter. High birefringence on the order of 10(-4) to 10(-3) over the near-infrared to short-wavelength infrared (0.75 to 2.3 mu m) spectral range has been obtained. The finite difference time domain method has been used for simulation. The center defect in the lattice forms the core and the remaining part represents the cladding. With phosphate glass (n(gl) = 1.56) as a base material, cladding consists of different segments formed by varying the air hole diameter resulting in strong form birefringence and reduced numerical aperture which leads to a large mode area. We inferred a relation between fiber symmetry and birefringence by varying the duty cycle of the designs. A significant reduction in beat lengths shows reduced power losses in the FM due to higher-order mode coupling. (C) 2015 Society of Photo-Optical Instrumentation Engineers (SPIE)