Review on cavity-resonant integrated grating filters

We review the investigations that have been carried out over the past decade on waveguide Fabry-Pérot microcavities with an embedded input/output grating coupler, devices often referred as Cavity-Resonant Integrated Grating Filters (CRIGFs). We will explain how the device geometry and use of various technological platforms (SiON, LiNbO₃ on insulator, GaAs) has permitted the fabrication of spatially localized wavelength filters that can operate from the near-infared to mid-infrared, subsequently enabling applications as laser spectral stabilization or as pixelated filter for (hyperspectral) imaging. Furthermore, we will show that the design can be adjusted to obtain critically coupled high-quality factor microresonators with a view to induce efficient second harmonic generation or, more generally, nonlinear parametric conversion. Finally, we will present our most recent investigations that have been devoted to the selective excitation of the supported higher order spatial modes and how the latter can be used to implement reconfigurable logical gates.