We have demonstrated new switching and gas-sensing effects in integrated optics using input and output grating couplers and Bragg reflector gratings with 1200 lines/mm on planar SiO(2)-TiO(2) waveguides. Switching is actuated by adsorption or desorption of water or other adsorbates on the waveguide surface through a change in the effective index of the guided modes under the grating. We derived theoretically the ultimate sensitivity limits of the grating devices employed either as switches or as gas sensors. Switching requires the adsorption and desorption, respectively, of less than one H(2)O monolayer. Sensors can detect variations in surface coverage of 1/100 of an H(2)O monolayer.
We describe a novel embossing technique for fabricating integrated optical components in hard and resistant inorganic waveguiding materials of good optical quality. The desired structure is embossed into a dip-coated deformable gel film prepared from organometallic solutions. Subsequent heat treatment transforms it into inorganic hard oxide material. We have successfully fabricated surface-relief gratings with 1200 lines/mm on SiO(2)-TiO(2) waveguides (with refractive index n(F) approximately 1.8, thickness d(F) approximately 120 nm, and loss <1 dB/cm). The embossed gratings served as input and output grating couplers and as Bragg reflectors. We propose to fabricate other integrated optical components, for example, channel waveguides, with this method.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.