Low-loss Ge-As-Se-Te fiber for high-intensity CO2 laser delivery

Abstract

High-purity Ge-As-Se-Te glasses have been well prepared via an effective double-distillation method. These glasses exhibit robust characteristics, withstanding input power levels as high as 12 W (68 kW/cm2). Utilizing extrusion-based fabrication, a large-core chalcogenide step-index fiber has been produced with a core diameter of 200 µm and a low optical loss of 0.78 dB/m at 7.25 µm. The fiber mode field area exceeded 26522 µm2. The fiber exhibits excellent transmittance in the whole mid and far infrared region of 2-12 µm, and its loss has been also certificated to be 1.85 dB/m at 10.6 µm by a CO2 laser. Further, the fiber is capable of high-intensity laser delivery of 16.13 kW/cm2, even under a high temperature of 150°C. At last, a high transmission efficiency of 44.9% has been recorded in this fiber, and the output power density is as high as 4.01 kW/cm2. All these results show that the fiber has the potential to be used in far-infrared laser machining and medical operation.