Highly nonlinear fibers for very wideband supercontinuum generation

Supercontinuum generation in highly nonlinear fibers (HNLF) pumped with femtosecond pulses is an area of large interest for applications such as broad band light sources, tunable femtosecond sources, frequency metrology, and fluorescence microscopy. In the last few years, a lot of focus has been put on optimizing photonics crystal fibers for supercontinuum application. In this paper, we will focus on conventional silica based HNLF, which e.g. have the advantage of precise dispersion control, and easy splicing to standard single mode fibers. We have performed a systematic experimental study of the effect of dispersion, of the HNLF as well as the input power to the HNLF. To pump the fiber we have build an femtosecond fiber laser consisting of a passive mode locked figure eight oscillator followed by an amplifier. The dispersion before coupling into the HNLF was optimized for broadest supercontinuum generation. Supercontinuum generation in both standard and polarization maintaining HNLF are studied.