Keywords: 
• GeTe-AgI /
• 硫系玻璃 /
• 远红外光纤 /
• 绿色环保

Abstract: When infrared (IR) is over 12 μm, conventional chalcogenide (ChG) fibers are confused by the multiphonon absorp-tion of Se, and novel glass materials for far-IR have become one of hot research points in recent years. Here, a novel ChG glass and fiber for far-IR without containing Se/As is well investigated. The glasses GeTe-AgI are purified by distillation and synthesized by melt-quenching method. The thermal properties and the infrared transmissions are reported. The step-index fiber, fabricated via a novel extrusion method, exhibits excellent transmission at 8–15 μm: < 24 dB/m in a range of 8–15 μm and 15.6 dB/m at 10.6 μm. The influences of oxygen contaminant and the purity of AgI on the glass transmission and fiber attenuation are discussed. Structural and physical properties of GeTe-AgI glass system are studied with differential scanning calorimetry and ellipsometer instrument. Optical spectra of GeTe-AgI glass system are obtained by spectrophotometer and infrared spectrometer. Main purification process with oxygen-getters (magnesium) is disclosed. The fiber attenuation is measured by the cut-back method with a Fourier transform infrared spectrometer. The lowest loss of this fiber can be reduced to 15.6 dB/m at 10.6 μm. The results show that these glasses are well trans-parent in a wide IR window from 1.7 to 25 μm, and these glass fibers can transmit light up to 15 μm, thus the GeTe-AgI glass system is one of good candidates for far-IR. The fiber attenuation can be reduced effectively by the reasonable purification and novel extruded-processing. These environment friendly fibers are suited for far-IR applications, such as greenhouse gas sensing and the power delivery of CO2 laser.