Influence of scattering on transmission through long-period fiber gratings and tunable microstructure fibers

Controlled optical scattering within or around an optical fiber provides a potentially useful means for adjusting its transmission characteristics. This approach can complement conventional methods based on the establishment of well-defined variations in the index of refraction of the core or the cladding of the fiber. We describe the use of a highly scattering submonolayer of nanoparticles deposited onto the fiber surface for adjusting the resonance wavelength, depth, and width of an in-fiber long-period grating filter. We also introduce a polymer-dispersed liquid-crystal material that has a thermally tunable scattering cross section and can be incorporated into the channels of a microstructure optical fiber; this system may provide the means for a fiber-based scattering switch.