Sensor Design Examples and Additional Considerations

Abstract

Optical fibers and integrated optics can be used as sensors in numerous ways [1–5]. However, practical and economic justifications limit the current applications to those cases where they offer significant advantages over the bulk optical approach (and electronic approach) [6]. As the technology of optical sensors is developed, so too have the capabilities and potentials of conventional sensors improved. In this regard, the integrated optics, which can take advantage of improvements in the microelectronic processing, may in the long run offer stiffer competition to the conventional sensors than fiber optic sensors would. In particular, silicon and III-V semiconductor based integrated optic sensors seem to hold great potentials. Nevertheless, so far the predominant number of applications employs optical fibers [7]. Part of the reason is that fiber optics is a very well established technology. On the other hand, the integrated optics offers myriad of choices for the substrates and waveguides: glass, silicon, LiNbO3, III–V semiconductor, polymers and nonlinear materials. This richness generates greater opportunities but probably also helps to slow down the progress in any particular application area.