Fiber gratings for WDM applications

Problems with fiber gratings include possible out-of-band reflections, cladding mode losses, temperature sensitivity, and of course, by themselves short period fiber gratings are reflecting elements, which can create, return loss problems in some applications. Also for a large channel count the problem of connecting a large number of fiber grating elements in a single component can become cumbersome. Cost reduction is also an important development that must continue in order to make fiber gratings more competitive. We discuss a few important aspects of fiber gratings for WDM components such as generating spectral profiles, dispersion compensation, and reliability of fiber gratings for long term commercial applications.