Fabrication and characterization of high quality GeSbSe reflowed and etched ring resonators

We demonstrate the fabrication of high Q Ge₂₈Sb₁₂Se₆₀ ring resonators in an all chalcogenide platform through electron-beam lithography, lift-off and thermal reflow. We achieve a Q factor of (3.9 ± 0.2) × 10⁵ in the reflowed ring resonators and (2.5 ± 0.2) × 10⁵ in the reactive ion etched ring resonators at 1550 nm. We measure the line roughness of these devices to estimate the scattering loss. We determine the material and scattering losses of the waveguide and find an additional 1.1 dB/cm excess loss from surface absorption. We fabricate Ge₂₃Sb₇S₇₀ waveguides with 0.6 dB/cm of losses and show that Ge₂₃Sb₇S₇₀ waveguides do not experience the same kind of excess loss when fabricated under the same conditions. This indicates the excess loss is related to the chemical composition of Ge₂₈Sb₁₂Se₆₀ compound.