低损耗Ge-As-Se-Te硫系玻璃远红外光纤的性能分析

中、远红外光学领域的发展,离不开低损耗光波导材料的发展,因此近年来远红外低损耗光纤一直是光学领域的热点之一.本论文在国内首次报道了一种基于挤压法的低损耗远红外光纤制备技术,获得了具有完整结构的远红外光纤,其损耗为:0.46 d B/m@8.7μm,1.31 d B/m@10.6μm,整体低于1 dB/m@7.2—10.3μm.在实验过程中,首先采用传统的熔融淬冷法和蒸馏纯化工艺制备了Ge-As-Se-Te玻璃样品.利用X射线衍射仪和热膨胀仪等测试了玻璃的结构和物理性质,分析了Ge对玻璃热学性质的影响;利用分光光度计、红外光谱仪等研究了玻璃的光谱性质;综合比较了还原剂铝、镁的除氧效果.最后采用挤压法制备了芯包结构光纤.实验结果表明:镁的除氧效果佳,新型挤压制备工艺和有效提纯技术共同推进了硫系光纤损耗的降低,所获得的Ge-As-Se-Te光纤具有远红外广谱应用的潜能(其透光波长接近12μm).

Investigation on Ge-As-Se-Te chalcogenide glasses for far-infrared fiber

With the development of infrared optics, low-loss waveguide materials are required. Especially, low-loss optical fiber development for far-infrared application has become a focus. Chalcogenide Ge-As-Se-Te(GAST) glasses and fibers for far-infrared light are prepared and investigated in this paper. The thermal properties and the infrared transmissions are reported. The influences of oxygen and hydrogen on the glass transmission and fiber attenuation are discussed. Low-loss GAST fiber with a structure of fine core/cladding is reported by a novel extrusion method (0.46 dB/m at 8.7 μm, 1.31 dB/m at 10.6 μm, base loss being under 1 dB/m from 7.2 to 10.3 μm). Here, the glasses are prepared by traditional vacuum melt-quenching and vapor distillation method. Structure and physical properties of GAST glass system are studied with X ray diffractions and thermal expansion instrument. Optical spectra of GAST glass system are obtained by spectrophotometer and infrared spectrometer. Main purification processes with different oxygen-getters (magnesium and aluminum) are disclosed. The fiber attenuation is measured by the cut-back method with an Fourier transform infrared spectroscopy spectrometer. The lowest loss of this fiber can be reduced to 1.32 dB/m at 10.6 μm, as it has a structure of Ge₂₀As₂₀Se₁₅Te₄₅ core and Ge₂₀As₂₀Se₁₇Te₄₃ cladding. The results show that these glasses are well transparent in a wide infrared window from 1.1 to 22 μm, and these glass fibers can transmit far-infrared light up to 12 μm, thus the GAST glass system is one of good candidates for far-infrared transparent materials. The fiber attenuation can be reduced effectively by the reasonable purification and novel extruded-processing. These fibers are suited for the power delivery of CO₂ laser.