Synthesis and processing of improved organic second-order nonlinear optical materials for applications in photonics

The synthesis and processing steps required to fabricate prototype electrooptic modulators from poled polymeric materials containing nonlinear optical chromophores are reviewed. These include (1) synthesis of chromophores with large first hyperpolarizabilities, (2) covalent incorporation of these chromophores into polymer lattices which can be processed into optical-quality thin films and poled by application of electric fields, (3) induction of lattice-hardening reactions which lock-in poling-induced noncentrosymmetric order, (4) creation of buried channel, nonlinear optical waveguides by reactive ion etching, by electron cyclotron resonance etching, and/or by photochemical processing, (5) coupling of buried channel electrooptic modulators to fiber optic transmission lines by photochemical processing and silicon V-groove pigtailing, (6) deposition of metal drive electrodes and evaluation of resulting prototype modulators. While the focus of this article is upon the synthesis and processing of materials, some consideration is given to device concepts including various Mach-Zehnder modulators, birefringence modulators, directional couplers, photonic voltage sensors, and photonic detection of electromagnetic radiation. Although poled polymers are of primary interest, other techniques for ultrastructure synthesis of noncentrosymmetric lattices are reviewed, including molecular self-assembly, sequential synthesis, and laser-assisted poling. © 1995 American Chemical Society.