Abstract

Most of the basic principles and techniques for photonic sensors have been known for more than 40 years but industrial applications are growing, fostered by increasing diffusion of low-cost telecommunication components and to the possibility of integrating many optical devices in a single chip. Intensity measurements are also benefited by both aspects; they keep being simple and low cost, even more than before, by using the advantages of electronic signal processing and high-scale integration. Also, novel reference intensity techniques minimizing limited resolution can be developed. Intensity measurements show advantages and drawbacks, which must be considered depending on the specific application to be developed.