摘要:

IntroductionPlanar optical waveguides have been of much interest in integrated optical circuit device applications. There have been many efforts to develop the planar waveguides using optically transparent materials such as silica and polymers.1,2Especially, polymers have a great advantage in defining waveguide patterns easily in the film using a photolithographic etching technique.3Also, an etching-free process has been proposed as a simpler technique to fabricate channel waveguides in polymers by using the photolocking of dopants inside the matrix.4,5Sol–gel-derived inorganic–organic hybrid materials (HYBRIMERs) composed of both organic and inorganic components have also been applied to fabricate the channel waveguides due to their superior optical properties and relatively high thermal stability compared with general optical polymers.6–8Recently, we have reported on the photolocking of photoinitiators in the HYBRIMER films.9–11The channel waveguide was successfully fabricated through selective UV exposure without any etching or a developing process called photochemical self-developing (PSD). However, the molecular structural changes during the photolocking process in the HYBRIMER are still unclear. And also, the used HYBRIMER consisting of methacrylate and silica/zirconia networks has relatively a high refractive index compared with pure silica, which can cause a high coupling loss when the planar optical devices are connected with a general silica fiber. To reduce the refractive index of a HYBRIMER, we incorporated a fluorine into the HYBRIMER by using heptadecafluorodecyl trimethoxysilane (PFAS). It was also expected that the fluorine incorporation into the HYBRIMER would lower its absorption loss.12However, in the fluorine-incorporated HYBRIMER, the methacryl groups in the HYBRIMER could be photodecomposed under UV exposure, which caused a decrease in the film thickness as well as in the refractive index.13Thus, it is necessary to understand the photochemical reactions in the fluorinated HYBRIMER with UV exposure to control its optical properties.Therefore, in this study, we first prepared the transparent fluorinated HYBRIMER film doped with a photolocking agent using a sol–gel method, confirming the structural changes during the photolocking process in the HYBRIMER. We investigated the effect of the type and density of the photoinitiator, UV fluence, and the illuminating wavelength region on the microstructures and optical properties. Finally, we demonstrated a linear channel waveguide and microlens array pattern using the PSD process.

ISSN:0959-9428    

DOI:10.1039/b403026e

出版商:RSC    

年代:2004

数据来源: RSC