Dispersion Management in Hybrid Optical Fibers

We report a new fiber concept, which is a hybrid design between classical step-index and photonic crystal fibers (PFCs). The proposed structure has a centrally located Ge doped core surrounded by a set of smaller microinclusions distributed in the cladding. In numerical investigations, we demonstrate that such a combination allows to arbitrarily shape the dispersion profile in a 1 μm wide spectral range while reducing the confinement losses with respect to air-hole PCFs exhibiting similar dispersion characteristics. We present simple guidelines for optimizing the structure. Finally, as a proof of concept, we show an adequately designed fiber which, even though is based on fused silica glasses and is an all-solid construction, is still capable of providing flat and all-normal dispersion characteristics (-37 ± 2.5 ps/nm/km) in broadband range from 1.3-2.15 μm and ultra-flat (-37 ± 0.2 ps/nm/km) for wavelength values from 1.5-1.9 μm.