Design of highly nonlinear photonic crystal fibers with flattened chromatic dispersion

Numerical investigation of high birefringence and nonlinearity tellurite glass photonic crystal fiber with microstructured core

In this paper, a novel photonic crystal fiber (PCF) based on tellurite glass with high birefringence and high nonlinearity is designed. Six small air holes arranged nearly rectangularly are added in the fiber core to form the near-elliptic core. By using the finite-element method with the help of COMSOL Multiphysics software, we investigate and simulate the birefringence, effective mode area, nonlinear coefficient, and the dispersion characteristics. Simulation results show that by optimizing the structure parameters of the core, at the wavelength of 1.55 µm, the birefringence is up to ${5.05} \times {{1}}{{{0}}^{- 2}}$; the nonlinear coefficient can reach a maximum of ${{1896}}\;{{\rm{W}}^{- 1}}\;{\rm{k}}{{\rm{m}}^{- 1}}$; moreover, the zero dispersion points can be obtained around the wavelength 1.55 µm. The proposed structure is easy to fabricate. The advantage of the proposed PCF has potential applications in polarization control, communication systems, and supercontinuum generation.

Design of All-Solid Dual-Concentric-Core Microstructure Fiber for Ultra-Broadband Dispersion Compensation

In this paper, the all-solid dual-concentric-core microstructure fiber (MSF) with ultra-broadband dispersion compensation characteristics is designed. The effects of microstructure fiber structure parameters on dispersion, phase-matching wavelength, and kappa value are analyzed by the multi-pole method and mode coupling theory. The average dispersion compensation multiple is 18.45, that is, 1 km long dispersion compensated MSF can compensate for the cumulative dispersion of standard single-mode fiber of 18.45 km in the wavelength range of 1385~1575 nm by optimizing MSF parameters. The change range of residual dispersion is within ±0.72 ps/(nm·km), and the splicing loss with standard single-mode fiber is controlled below 5 dB within the compensation bandwidth of 190 nm. Compared with the air hole-quartz structure dual-concentric-core microstructure fiber, the designed fiber reduces the difficulty of fiber drawing, is easy to splice with standard single-mode fiber, and has wider compensation bandwidth as well as larger compensation multiple than the existing microstructure fiber. This lays a solid foundation for the optimization of dense wavelength division multiplexing networks and the construction of all-optical networks.

Design of a pentagonal photonic crystal fiber with high birefringence and large flattened negative dispersion

Novel pentagonal photonic crystal fiber with high birefringence, large flattened negative dispersion, and high nonlinearity is proposed. The dispersion and birefringence properties of this structure are simulated and analyzed numerically based on the full vector finite element method (FEM). Numerical results indicate that the fiber obtains a large average dispersion of -611.9  ps/nm/km over 1,460-1,625 nm and -474  ps/nm/km over 1425-1675 nm wavelength bands for two kinds of optimized designs, respectively. In addition, the proposed PCF shows a high birefringence of 1.67×10^-2 and 1.75×10^-2 at the operating wavelength of 1550 nm. Moreover, the influence of the possible variation in the parameters during the fabrication process on the dispersion and birefringence properties is studied. The proposed PCF would have important applications in polarization maintaining transmission systems, residual dispersion compensation, supercontinuum generation, and the design of widely tunable wavelength converters based on four-wave mixing.