Bimodal Resonance Phenomena—Part II: High/Low-Contrast Grating Resonators

Several groups are currently working on integrated optical resonators. In this context, one of the most interesting implementations is based on high-contrast gratings, featuring high-Q Fano resonances. Mastering these phenomena can potentially open up the possibility to exploit such devices for the implementation of vertical-coupled filters or compact monolithic lasers. To this aim, in this paper, the novel analytic framework introduced in Part I is applied to complement the design guidelines present in the literature. Through explicit expressions of the loop gain eigenvalues, it is possible to predict the positions and quality factors of resonances in crossing and anticrossing points. Moreover, a quantitative connection between these points and Fano resonances is established. The framework presented in this paper has been useful for identifying, in a low-contrast grating, resonance features similar to those well known in high-contrast structures.