Control of the chromatic dispersion of photonic crystal fibers for supercontinuum and photon pairs generation

The interplay between chromatic dispersion and nonlinear effects is crucial for an efficient exploitation of non linear propagation in photonic crystal fibers (PCF). Once a PCF preform has been prepared, changing the parameters that control the fabrication process it is possible to adjust the dispersion properties of the fiber. In addition, it is particularly useful to develop postprocessing techniques that enable a fine adjustment of the dispersion along a section of PCF. The tapering of PCF, using a fusion and pulling technique, has been established as a rather useful technique to engineer the dispersion properties along tens of centimeters. Some of our recent experiments demonstrate that the use of erbium doped PCF enables an optical control of the dispersion through optical pumping of the rare earth ions. Since our interest is focused on the development of fiber light sources, we will present several experiments on supercontinuum and photon pairs generation, through degenerate four-wave mixing (FWM), in order to illustrate the control that one can achieve on the optical spectra of these light sources by tailoring the dispersion of the fibers.