we propose an electrically driven electro-optical modulator integrated with the phase-change material Ge2Sb2Te5 (GST). This modulator incorporates a hybrid Si-GST-Cu waveguide with input and output Si waveguides. For the waveguide modulator with an active segment of 0.2 μm 2, the switched phase is stable with off/on extinction ratios of >5.4 dB on the entire C-band. Since the phase-change of GST only consumes energy during the stated transitions, the energy consumption per bit for this nano-size device is ideally low on the order of sub-nJ per cycle.

In this article, the chalcogenide slot waveguide is theoretically studied, and the highest power confinement factors of the slot region and the cladding region are obtained to be 36.3% and 56.7%, respectively. A high-sensitivity chalcogenide slot microring resonator sensor is designed and fabricated by electron-beam lithography and dry etching. The structure increases the sensitivity of the sensor compared with the conventional evanescent field waveguide sensor. The cavity has achieved a quality factor of 1 × 10⁴ by fitting the resonant peaks with the Lorentzian profile, one of the highest quality factors reported for chalcogenide slot microring resonators. The sensor sensitivity is measured to be 471 nm/RIU, which leads to an intrinsic limit of detection of 3.3 × 10­⁻⁴ RIU.

We demonstrate high quality (Q) factor microring resonators in high index-contrast GeSbSe chalcogenide glass waveguides using electron-beam lithography followed by plasma dry etching. A microring resonator with a radius of 90 μm shows an intrinsic Q factor of 4.1 × 10⁵ in the telecom band. Thanks to the submicron waveguide dimension, the effective nonlinear coefficient was determined to be up to ∼110 W⁻¹m⁻¹ at 1550 nm, yielding a larger figure-of-merit compared with previously reported submicron chalcogenide waveguides. Such a high Q factor, combined with the large nonlinear coefficient and high confinement, shows the great potential of the GeSbSe microring resonator as a competitive platform in integrated nonlinear photonics.

We demonstrate the high quality (Q) factor microdisk resonators in high index-contrast chalcogenide glass (ChG) film GeSbSe using electron-beam lithography followed by plasma dry etching. High confinement, low-loss, and single-point-coupled microdisk resonators with a loaded Q factor of 5×10⁵ are measured. We also present pulley-coupled microdisk resonators for relaxing the requirements on the coupling gap. While adjusting the wrap-around coupling waveguides to be phase-matched to the resonator mode, a single specific microdisk radial mode can be excited. Moreover, the thermal characterization of microdisk resonators is carried out to estimate the thermo-optic coefficient of 6.7×10⁻⁵/K for bulk ChG.

Ge-Se thin film waveguide is used in optical devices because of its excellent optical properties. We investigated the structural and optical properties of as-deposited and thermally annealed Ge₁₈Se₈₂ films and the associated waveguides. The optimized annealing condition at 170 °C was determined for Ge₁₈Se₈₂ films. This study reveals that the annealing process can reduce the density of homopolar bonds and voids in the films. After the annealing process, Ge₁₈Se₈₂ waveguides with the dimensions of 1.0 µm×4.0 µm and 1.5 µm×4.0 µm present 0.22 dB/cm and 0.26 dB/cm propagation loss reduction, respectively. This finding suggests that thermal annealing is an appropriate method for improving the performance of chalcogenide glass devices.