Organic–inorganic materials for fabrication of integrated optical circuits

In the last few years, ORganically MOdified SIlicates (ORMOSILS) [R x Si(OR) 4− x ] prepared by sol–gel process were particularly attractive for integrated optics fabrication. A composition based on 3-(trimethoxysilyl)propylmethacrylate (MAPTMS) has already allowed the industrial fabrication of optical integrated devices. For this kind of materials, the polymerization of the organic network is typical of free radical curing. In this work, we try to obtain waveguides with another hybrid precursor [2-(3,4-epoxycyclohexylethyltrimethoxysilane)] using cationic polymerization. The main advantage of cationic polymerization is its ability to allow spontaneous cure reaction in presence of oxygen, in contrast with radical polymerization. We choose cycloaliphatic compounds because of their well-known high polymerization rates. The polymerization of the organic network of this hybrid material requires a cationic photoinitiator. The purpose of this paper is dedicated to the inorganic part of the material. Hydrolysis and polycondensation are followed by 29Si NMR. The main objective is to obtain the highest reactive multifunctional oligomer with the lowest OH groups content. Based on our results, we obtained 3D waveguides with a cross-section of 5 μm × 5 μm.