Crossings in photonic crystal fiber with hybrid core and design of broadband dispersion compensating photonic crystal fiber

Abstract A photonic crystal fiber (PCF) with sub-wavelength air inner core and Ge-doped concentric ring outer core is proposed. The full vector finite element method with perfectly matched layer is used for simulation. Mode crossing phenomenon which can be controlled through the hollow core diameter is investigated. A PCF with an effective compensated dispersion range of ±1.38 ps/nm/km from 1460 nm to 1637 nm wavelength is designed. The dispersion compensating PCF (DCPCF) can compensate for the dispersion and dispersion slope of a standard single mode fiber (SMF) at the same time. The kappa value matches very well with that of the commercial single mode fiber. Moreover, the figure of merits inside air core region of the proposed DCPCF is improved by 21.3 dB at 1550 nm wavelength compared to a hollow core photonic bandgap (PBG) fiber. This field enhancement can effectively reduce the material loss and the nonlinear accumulation in dispersion compensation fibers.