Design of large mode area total internal reflection photonic crystal fiber for high power fiber laser

The nonlinear effect and material damage existing in high power fiber lasers restrict their output power. A large mode area fiber, which could reduce the power density and improve the nonlinear threshold, is one of the solutions to the problem. A photonic crystal fiber with air holes at wavelength scales was designed based on the effective index model and finite element analysis. The single-mode properties as well as the influence of structural parameters on the mode area and dispersion were investigated. Considering practical applications, we designed a large mode area photonic crystal fiber, operating in the range of 0.40~1.55 m, mode area between 112.74~258.87 m2, centering at 1.27 m with dispersion compensation ability. Our investigations may provide new references to the optimization and fabrication of large mode area fiber for high power fiber lasers.