Waveguide gratings used in laser technology, optical sensing or optical communications have to serve different specific
purposes and, hence, have to have specific optical properties which can be tailored to a large extent. Characterization
methods are required not only to measure the actual effect of a Bragg grating or long period grating under consideration
but also to unveil the cause, i.e. to determine its spatial structure. This paper reviews the present status of the respective
experimental characterization techniques. The methods emphasized rely on phase sensitive reflectometry together with
advanced inverse scattering evaluation algorithms.
Polarization mode dispersion (PMD), polarization dependent loss (PDL) and chromatic dispersion (CD) of fiber optic components and fiber transmission links are key issues in fiber optical communication. Of interest are the respective static values as well as their variations in time which might be due to environmental changes or due to rerouting. Basic aspects will be briefly addressed, a variety of standard and state-of-the-art characterization and monitoring techniques will be reviewed and recent experimental results will be presented.