Fabrication and characterization of Ge₂₀Sb₁₅Se ₆₅ chalcogenide glass rib waveguides for telecommunication wavelengths

We report on the fabrication and optical properties of Ge ₂₀Sb₁₅Se₆₅ chalcogenide glass rib waveguides on a single photonic chip.Radio-frequency magnetron sputtering method is employed to deposit 1.36-μm-thick films and reactive ion etching with CHF₃ is used to pattern 0.76-μm-deep rib waveguides of 1-4 μm wide with low surface roughness and vertical sidewalls.Using lensed fibers, the insertion losses for rib waveguides of different widths are measured and propagation losses are estimated to be lower than 1 dB/cm.Finite difference method simulations and refractive index/curve fitting are used to observe a moderate normal dispersion of the waveguides at 1550 nm.