Photonic integrated optics encompass optical devices that manipulate properties of light such as wavelength conversion, polarization, phase, intensity in order to design functional active and passive planar optical elements on various platforms such as polymers, semiconductors, oxides. Building on a substrate used for mechanical support, the device is isolated from the substrate optically with a low index buffer layer. Confining light in a high index medium over the buffer layer with local index modulation, light can be made to propagate in quasi-one dimensional akin to an electrical wire. Such devices as polarization splitters, multimode interferometers, Mach-Zehnder interferometers, ring resonators, beam splitters are typical examples. In this field, we are studying applications of hybrid integrated optical devices to add/drop filters for telecommunication applications as well as to displacement meaurements at the nanoscale. Concentrating on ring resonator based add/drop multiplexers, where large ring radii leads to narrow FSRs, we exploit the hybrid material system to engineer large FSRs with large resonator diameters.