GG-IAG大模场光纤制备与增益性能的研究

Research on the fabrication and gain performance of GG-IAG large mode area fiber

基于GG-IAG光纤理论模型,设计了掺Nd3+磷酸盐GG-IAG光纤玻璃材料配方;采用管棒法制备了GG-IAG光纤预制棒,在530℃下拉制了不同直径(200μm-500μm)的掺Nd磷酸盐GGIAG大模场光纤;测试了光纤的光谱参数与增益性能,然而,由于光纤存在模式泄漏损耗,导致其增益性能不高。为了提高GG-IAG光纤的增益性能,采取磁控溅射方法,分别在芯径为130μm、160μm和200μm的GG-IAG光纤包层表面蒸镀200nm的Ag膜作为全反射膜,使得泵浦光被束缚在光纤中,从而提高了光纤的泵浦效率。实验结果表明,在光纤参数相同的情况下,镀Ag膜后光纤的放大效率分别为50%、41.88%、24.33%;而未镀Ag膜光纤的放大效率分别为26.87%、22.8%、15.87%。说明光纤表面镀膜能够显著改善GG-IAG光纤的增益性能,研究结果对GG-IAG光纤的应用具有指导意义。

As a new type of large mode area fiber,gain-guided and index-antiguided （GCrlAG） fiber has been widely concerned. Based on the GG-IAG fiber theoretical model,the formula of Nda＋ doped phos- phate GG-IAG fiber glass material was designed in this paper. The GG-IAG fiber preform was prepared by tube bar method. The Nd^3＋ doped phosphate GG-IAG large mode area fibers with different diameters （200--500μ m） were drawn at 530 ℃ The spectral parameters and gain performance of the GG-IAG fiber were tested. However,the gain performance is poor due to the leakage loss of the optical fiber. In order to improve that,the effect of coating Ag film on the gain performance of GG-IAG fiber was stud- ied. The experiments were based on the GC,-IAG fiber with different core diameters,such as 130 μm,160 μm and 200 μm respectively. By magnetron sputtering,a 200 nm-thick Ag film was applied on the sur- face of the fiber cladding as a total reflection film,the pump light was bound to the optical fiber,thereby improving the pumping efficiency. The experimental results show that the Ag film has higher signal am- plification efficiency than that without Ag film with the same core diameter. And the amplification efficiency of Ag coated fiber is 50%,41.88% and 24.33% respectively,while that of the unplated Ag film fiber is 26.87% ,22. 8% and 15.87% ,respectively. It shows that the optical fiber surface coating can significantly improve the gain performance of GG-IAG fibers,and the results are of guiding significance for the application of GG-IAG fibers.