Integrated optical cavities like guided mode resonance filters (GMRF) allow for new functionalities in integrated optical setups. Cavity-resonator-integrated guided-mode resonance filters (CRIGFs) have been proposed as filters with narrow bandwidth and small footprint. It is challenging to accurately compute their performance due to the highly resonant behavior and due to the multi-scale nature of the devices. In this project we use light scattering and resonance mode computations to investigate CRIGFs and to optimize their performance.