Numerical simulation of the heavily Ge-doped polarization-maintaining fiber with normal dispersion

The heavily germanium (Ge)-doped silica fiber assisted by two air holes in the cladding exhibits high nonlinearity and birefringence, low loss and normal group velocity dispersion (GVD) for two fundamental modes (FMs). When the 1 920 nm and 0.1 ps pump pulse with 100 kW peak power is coupled into the 0.5-m-long fiber and polarized along one of two principle axes, the generated spectra can cover the wavelength range around 1 000–2 500 nm at −20 dB. Furthermore, the output pulse has an excellent coherence in the whole wavelength range.