*** 9805388 Tavlykaev The primary goal of the completed Phase I effort was to prove the feasibility of hig-reflectance low-loss silicon gratings on LiNbO3 waveguides. We showed theoretically and demonstrated experimentally that a substantialperturbationof the effective mode index ina LiNbO3 waveguide can be achieved with a high-index Si overlay without increasing optical loss for the guided mode. This phenomenon was used to build a high performance Si Distributed Bragg reflector with 80% reflectivity. Subsequently, a narrowband asymmetric Fabry-Perot filter with electro0optical tunability was realized using a Si grating on a LiNbO3 waveguise. The filter was tested in a hybrid laser-filter module. The developed technology of high performance DBR gratings using Si-on-LiNbO3 structures is useful in developing a variety of advanced devices, in particular, filters and compact waveguide laser sources, such as CW, mode locked, Q-switched, and tunable lasers. These devices are sorely needed inthe cable and telecommunication industry, especially in WDM networks. ***
