A dual-concentric-core photonic crystal fiber for broadband dispersion compensation

We propose dual-concentric-core photonic-crystal fibers that may be useful in compensating for the dispersion of a single-mode fiber over nearly the entire optical communication wavelength range. The dual concentric core is composed of a germano-silicate high-index inner core and a outer core that is formed by shifting the air holes of the first layer of cladding to the inner core. The dispersion characteristics of the fiber are theoretically investigated by using the semi-vectorial beam propagation method. The influence of the core structures on the dispersion characteristics are reasonably analyzed by using the effective index model. The dispersion of the fiber is larger than -450 ps/(km.nm) in the range from 1450 nm to 1600 nm and reach as -600 ps/(km.nm) around 1550 nm. Thus, the proposed photonic-crystal fiber can compensate for the dispersion of a conventional single-mode fiber to within 0 2 ps/(km.nm) over the S, C, and L bands.