Fabrication And Characterization Of Yb³⁺doped Silica-based Core For The High-power PCF Laser

The high-quality Yb³⁺-doped laser glass is the basic substance for the preparation ofhigh-power photonic crystal fiber laser. Compared to the Yb³⁺-doped multiple copies glassYb³⁺-doped quartz glass has a higher melting temperature （about 1800℃or so）, a dopedphotonic crystal fiber can be drown using a relatively simpler and flexibler accumulationmethod. Therefore, the Yb³⁺-doped quartz glass is more suitable to be used as a kind ofcore material of high-power fiber lasers.Using a modified chemical vapor deposition （MCVD） process in the preparation ofdoped photonic crystal fiber, not only can not create a high concentration doped fiber, butalso its thick silica cladding exceeds the synthetic distance between the coherent beamcombination. Therefore, it is necessary to explore a more efficient preparation process tomeet the needs of the development of high-power photonic crystal fiber laser. This papermainly covers the following aspects:First, the doping mechanism of ytterbium ions in the quartz glass is analyzed toidentify the reasons for the ytterbium ions cluster and bring forward some measures toreduce the ytterbium ions concentration quenching phenomenon which occurs in thequartz glass matrix. The introduction of an appropriate amount of aluminum ions in thematrix can effectively improve the solubility of the ytterbium ions.Secondly, the experiments of the preparation process of the ytterbium-doped quartzglass are summarized and the problems which exist and the improvement program arepointed out. Besides, a new non-CVD combined with the solution doping method isexplored as a new process of the Yb³⁺-doped quartz glass. With the new process,it havefabricated a seris of high-quality Yb³⁺-doped quartz glass with a high ion concentration upto 12000 ppm.Finally, a seris of Yb³⁺-doped PCF sample with the the ideal cross sectionstructure ,whose core material is the quartz glass sample,are made using the improvedaccumulation process. Besides, the problems and defects of the accumulation method inthe preparation of doped PCF are carefully analyzed and some programs to optimize thefabrication process are put forward. The improvement of the fabrication process of ytterbium-doped quartz glass have notonly promoted the development of high-power PCF lasers, but also laid the foundation forpreparation of the higher-quality doped laser glass.