Tunable dual-polarization photonic ring resonator filters for OH-supressed ground-based astronomy

Currently, ground-based infrared astronomical observations suffer from an irreducible background generated by emission from OH (hydroxyl) molecules in the upper atmosphere. However, if narrow-band notch filters could be incorporated into the optical path of astronomical instruments, then this background could be effectively suppressed with very little accompanying loss of signal from the astronomical sources of interest. Photonic ring resonators are one technology that provides a promising method of generating such notch filters. We describe our efforts to resolve heretofore-intractable engineering problems in the application of photonic ring resonators, improving their performance to the point where they can be usefully integrated with functional astronomical instrumentation.