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.