小芯径硫系玻璃光纤的制备及其非线性光学应用

通过动态蒸馏提纯技术制备了高纯Ge-As-Se和Ge-As-S硫系玻璃。采用两步棒管法拉制了以Ge-As-Se玻璃为纤芯、Ge-As-S玻璃为包层的小芯径阶跃折射率光纤, 并使用飞秒激光抽运光纤测试了超连续谱的产生。以Al 和GaCl₃分别作为除氧剂和C/H纯化剂可以有效消除玻璃中的C、H和O杂质。制备的GeAsSe/GeAsS光纤在2~9 μm波段表现出优异的传输性能, 光纤数值孔径约为1.3; 采用重复频率为10.5 MHz、脉冲宽度为320 fs、中心波长为4.0 μm、峰值功率为4.6 kW激光抽运长度为22 cm、芯径为6 μm的光纤, 获得了覆盖1.9~8.2 μm、光谱平坦度为±10 dB、平均功率为4.5 mW的超连续谱。

Fabrication and Application of Small Core Chalcogenide Glass Fibers in Nonlinear Optics

High purity Ge-As-Se and Ge-As-S chalcogenide glasses were synthesized by a dynamic distillation technique. Small-core step-index fibers with Ge-As-Se glass core and Ge-As-S glass cladding were fabricated through a two-step rod-in-tube approach. Supercontinuum generation was measured using a femtosecond laser as the pump. The impurities associated with C, H and O could be efficiently eliminated when Al and GaCl₃ were used as the oxygen getter and C/H scavenging agent, respectively. The as-fabricated GeAsSe/GeAsS fibers have a numerical aperture of ~1.3, and show good transmitting property in the 2-9 μm spectral range. When a 22 cm long fiber with a core diameter of 6 µm is pumped with 4.6 kW peak power and 320 fs pulses at a repetition rate of 10.5 MHz at 4.0 μm, supercontinuum spanning from ~1.9 to ~8.2 µm is generated with a dynamic range of ±10 dB and an average power of ~4.5 mW.