Fabrication of Mid-IR As-Se Chalcogenide Glass and Fiber With Low Scattering Loss

The addition of metallic deoxidizer is effective in reducing oxygen-containing impurities during the preparation of the chalcogenide glass. However, excessive metal can introduce undesirable background scattering in the glass host, and increase the optical fiber loss. In this paper, we propose an effective approach to address this issue by introducing micron-sized filters into a multi-stage dynamic distillation process. Experimental results show that, after removing these particles, the 20-mm-thick As ₄₀ Se ₆₀ glass exhibits a transmittance of 60%, which is close to the theoretical value. Further study reveals a transmittance of up to 60.6% at wavelength of 2.94 μm laser using a G1 glass with low hydroxyl group content. Additionally, an AsSe/GeAsSe fiber with core-size of 200-μm diameter was fabricated via isolated-extrusion method, the fiber exhibits a minimum loss of 0.37 dB/m at 5.7 μm and maintains a low scattering loss of about 0.5 dB/m at the wavelength range from 2.5 to 3.5 μm. The fiber demonstrates an ability of enduring an incident CO ₂ laser power of 7.2 W and outputting power density of 2.33±0.02 kW/cm ² at a wavelength of 10.6 μm, which is higher than the record of 2.1 kW/cm ² with a water-cooled Ge-As-Se fiber in previous work.