Photonics modulators, electro-optic switches

Organic compounds with delocalized 7r-electron systems are leading candidates for nonlinear optical (NLO) materials, and interest in these materials has grown tremendously in the past decade [108-118]. Reliable structure-property relationships—where property here refers to first-order (linear) polarizability a, second-order polarizability and third-order polarizability y—are required for the rational design of optimized materials for photonic devices such as electro-optic modulators and all-optical switches. Here also, quantum-chemical calculations can contribute a great deal to the establishment of such relationships. In this section, we illustrate their usefulness in the description of the NLO response of donor-acceptor substituted polymethines, which are representative of an important class of organic NLO chromophores. We also show how much the nonlinear optical response depends on the interconnection between the geometric and electronic structures, as was the case of the properties discussed in the previous sections [ 119]. 

Waveguide components are also applied in photonic devices. Based on polymers, these can be easily manufactured at low cost, with typical applications ranging from computer backplanes that combine electrical and optical cables, thermo-optical switches, optical splitters of multichannel high-density planar lightwave circuits to polyimide-based electro-optical (EO) modulators. 

---