The physic-chemical compatibility of passive cladding and poled Dispersed Red 1 (DR1) doped ultraviolet (UV) curable polymer SU-8 was investigated. The multilayer films consisting of DR1/SU-8 core and Norland Optical Adhensive 73 (NOA73), SU-8, polydimethylsiloxane (PDMS), or polymethylmethacrylate (PMMA) upper-cladding were fabricated on the silicon substrate, respectively. The interface morphologies were characterized through scan electronic microscope. Parallel plate electric field poling was carried out to align the polarity of chromophores in SU-8. The core–cladding interface with no chemical erosion or delamination was obtained by adopting an excess UV exposure and higher temperature dealing when NOA73 was used as the upper-cladding. The root mean square roughness of the upper-cladding surface was measured by atomic force microscope to verify the poling process. The electro-optic (EO) signal response amplitude of these multilayer films was used to characterize the polarizability alignment of DR1 chromophores by means of Teng–Man method after poling. Resistivity of claddings was measured at the glass transition temperature of DR1/SU-8 to explain the EO response difference. The configuration of NOA73/(DR1/SU-8) exhibited the best EO performance and time relaxation in amplitude within 550 h by prolonging the cooling time in poling process. A channel waveguide was fabricated to study the poling-induced optical loss. The results show that the selection of passive cladding with favorable electrical and chemical property is essential to establish optical nonlinearity in the dye–polymer system.
Xiaoqiang Sun,Ying Xie,Xuliang Zhao,Dehui Li,Shimin Zhao,Yuanbin Yue,Xibin Wang,Jian Sun,Lei Liang,Changming Chen,Daming Zhang,Fei Wang,Zhiyuan Xie.
Applied Surface Science,285,Part B,469-476(2014)