Development of highly nonlinear polarization maintaining fibers with normal dispersion across entire transmission window

A determined polarization state of light is required in nonlinear optics applications related to ultrashort and single-cycle light pulse generation. Such short timescales require up to one full octave of the spectral width of light. A fiber-based, pulse-preserving and linearly polarized supercontinuum can meet these requirements. We report on the development—from linear simulations of the fiber structure, through fabrication of physical fibers to their versatile characterization—of polarization-maintaining, highly nonlinear photonic crystal fibers, intended for femtosecond pumping at a wavelength of 1560 nm. A full octave of linearly polarized light around this wavelength would enable the covering of amplification bandwidths of the three major fiber amplifiers, from ytterbium-doped systems up to thulium- and holmium-doped fiber amplifiers, with a coherent, linearly polarized seed signal. At the same time, an all-normal chromatic dispersion profile over an entire transmission window, and a small dispersion of nonlinearity in the developed fibers, would facilitate use of commercially available femtosecond fiber lasers as pump sources for the developed fibers.