Dispersion Engineering of Waveguide Microresonators by the Design of Atomic Layer Deposition

In this work, we demonstrate dispersion engineering of silicon nitride waveguide resonators with atomic layer deposition (ALD). We conducted theoretical and experimental analyses on the waveguide dispersion with air cladding, hafnium oxide (HfO₂) cladding, and aluminum oxide (Al₂O₃) cladding. By employing ALD HfO₂ as the cladding layer, the dispersion of waveguide can be tuned to a finer degree in the normal regime at a wavelength of 1550 nm. On the other hand, using ALD Al₂O₃ cladding provides the waveguide dispersion that spans regimes in normal, near-zero, and anomalous dispersion.