High index-contrast GeSbSe chalcogenide waveguide for integrated nonlinear photonics

We fabricated high-index-contrast GeSbSe nonlinear waveguides using electron beam lithography (EBL) and inductively coupled plasma (ICP) etching. In a 0.75 cm long waveguide, we observed self-phase modulation (SPM) with a maximum nonlinear phase shift of 2.5π and a four-wave mixing (FWM) conversion efficiency of -37.8 dB. By engineering the waveguide dispersion, we achieved a supercontinuum (SC) spectrum spanning over 700 nm and demonstrated a Raman soliton self-frequency shift (SSFS) with a low pump threshold (∼6.5 mW) and tunable wavelength in a 1.0 cm-long GeSbSe waveguide. These results highlight the strong potential of GeSbSe-based platforms for integrated nonlinear photonics applications.