Integrated high-Q reflective cavities

We report on the demonstration of several integrated slab-waveguide-based concentric Fabry-Perot resonators employing holographic Bragg reflectors as curved 2D cavity mirrors. The cavities, fabricated in a low-loss silica-on-silicon slab waveguide using high-fidelity deep ultra violet photolithographic fabrication, exhibit Q-factors approaching up to 10 degrees which are competitive with silica-based ring resonators. The Q-values achieved indicate very high slab waveguide homogeneity providing wavefront stability and extremely low loss from the volume-holographic lithographically scribed mirrors. Compared to silica-based ring resonators, the folded Fabry-Perot resonator design allows access to a substantially larger free spectral range by cavity shortening. Pathways to the implementation of high-reflectivity and low loss distributed reflectors promise new directions in photonic integration with applications in sensing, filtering, and signal transport.