基于锗酸盐玻璃双包层高掺杂铥光子晶体光纤的制备与性能研究

Thulium-doped fiber lasers have extensive application prospects in the military, medical, communications, industrial and other fields, for its emission spectrum covers 1.5 to 2.2 μm band, which is located at eye-safe area. In particular, the laser output wavelength of 2.0 μm provides for the infrared laser pump source. At present, Thulium-doped silica fiber laser exists some problems：The poor output beam quality, the small mode area, few-mode operation and other issues. These restrict further enhance of performance of thulium-doped silica fiber. In the project, to find the best doping concentration ratio of thulium-doped ion, the mechanism of multi-component germanate glass is analyzed theoretically. For contradiction between single mode and large mode area, by adjusting the filling ratio, the core diameter and the pitch of holes etc, a large numerical aperture, large mode area and single-mode operation of the double-clad photonic crystal fiber is designed. Experimentally, under the guidance of the appropriate theory formulation of germanate glass component, by adjusting micro-regulating germanate glass composition and optimizing their preparation process, and analyzing its physical and chemical properties, the problem of lower concentration of thulium-doped ions will be solved. Using the maturely mastered technology of tube-rod stacking and photonic crystal fiber drawing, the double-clad photonic crystal fiber based on thulium-doped germanate glass will be prepared and consecutively a desired fiber will be drawled. Finally, thulium-doped fiber lasers with the high-performance and high-power will be further carry out research based on the fiber, and which will help them to be widely applied in high power Tm-doped fiber laser field theoretically and experimentally.

掺铥光纤激光器发射谱覆盖1.5~2.2 μm，位于人眼安全区，在军事、医疗、通信、工业等领域应用广泛，尤其是2.0 μm的激光输出，可解决中红外激光泵浦源的燃眉之急。目前掺铥石英光纤激光器存在输出光束质量差、模场面积小、少模运转等问题，限制其进一步性能提高。本项目拟在理论上对掺铥离子多组分锗酸盐玻璃的机理进行系统研究，找到最佳掺铥离子浓度配比的光纤材料；针对大模场面积与单模矛盾，通过调整占空比、孔间距以及纤芯直径等参数，设计具有大数值孔径、大模场面积的单模双包层光子晶体光纤。实验上，通过对锗酸盐玻璃中各组分之间的配比微调及其制备工艺的优化，解决玻璃中铥离子浓度掺杂较低的问题；采用已掌握的管棒堆积法和拉制光子晶体光纤工艺，制备双包层掺铥锗酸盐玻璃光子晶体光纤预制棒和光纤，在此基础上，开展高性能、高功率掺铥光纤激光器研究，为加快我国在高功率掺铥光纤激光器领域研究步伐提供理论基础和实验依据。

掺铥光纤激光器发射谱覆盖1.5到2.2微米波段，位于眼安全区，在军事、医疗、通信、工业等领域应用前景广泛，尤其2.0微米波段的激光输出可解中红外军用激光泵浦源的燃眉之急。而目前石英掺铥光纤激光器存在输出光束质量差、模场面积小、少模运转等问题，限制掺铥石英光纤激光器性能进一步提高。本课题理论上对多组分锗酸盐基质掺杂机理展开分析，找到最佳掺杂铥离子浓度的配比。针对大模场面积与单模的矛盾，通过调整占空比、孔间距以及纤芯直径等参数，设计出数值孔径大0.6、模场面积大和单模运转的双包层光子晶体光纤。实验上，实现最佳锗酸盐玻璃组份理论配方，通过微调控锗酸盐玻璃的组成和优化其制备工艺，并分析其物化性能，实现高杂掺杂铥离子浓度(8000ppm)。采用已掌握较成熟的管棒堆积法和拉制光子晶体光纤工艺，制备出双包层掺铥锗酸盐玻璃光子晶体光纤预制棒和拉制出光纤，j基于该光纤，开展高性能、高功率掺铥光纤激光器研究工作,实现稳定的线宽小于3kHz，边模抑制比达72dB的单模窄线宽单频1.95 μm光纤激光输出。