While the basic principles on which integrated optic sensors (IOSs) are based are the same as for fiber optic sensors, the two fields have developed at different paces and with slight different targets. Fibers have the unique capability of operating over extended gauge lengths (even km!) in either point sensing or distributed sensing format. In the former case, the FOS is configured in such a way that monitoring of the measurand occurs at a specified location along the fiber (generally at its distal end); in the latter case, the values of the measurand (e.g. temperature or strain) are probed as a function of the position along the fiber. Remote measurements are made possible by the low attenuation characteristic of an optical fiber. Integrated optics (IO), on the other hand, has been developed with the aim of implementing multi-functional miniaturized circuits, possibly of size of a few cm, if not mm.