量子点掺杂的光纤放大器由于发光波长可调谐而倍受关注。然而却因为材料的稳定性差和非辐射的俄歇复合效应而导致光学增益效果不理想。为此，我们设计以PbSe量子点溶液为纤芯，SiO2玻璃为包层的光纤光放大装置，提出并研究改善光放大效果的方法：（1）以稳定性更强的PbSe/CdSe核壳量子点溶液为纤芯制作液芯光纤，通过抑制其发光强度的衰减来增加光学增益；（2）在适当的泵浦光激发下，使纤芯中的量子点产生多激子态，通过调节平均激子个数得到最佳的光学增益；（3）采用超短脉冲激发，抑制纤芯内量子点由于多激子态而产生的俄歇复合效应，提高受激辐射的发生概率。最后，优化各项参数，预期达到~20 dB的光学增益。目前还未查到国内外关于采用核壳量子点作为掺杂剂的液芯光纤的研究和多激子态下的光学增益的报道。另外，采用超短脉冲激发量子点光纤是有效的抑制俄歇复合的新方法。此项研究成果对于量子点光纤放大器的研制具有重大意义。

Quantum dot (QD) -doped optical fiber amplifier has attracted much attention because of the tunability of the emission wavelength. However, the optical gain is not ideal because of the poor stability of QD material and non-radiative auger recombination effect. For these reason, we design optical fiber amplifier using PbSe QD solution as the fiber core, and SiO2 as fiber cladding and propose methods for improving light amplification effect: (1) the optical gain can be improved by using PbSe/CdSe core/shell QD as fiber core due to its more stable property; (2) the multi-exciton state for QD in the fiber core can be generated under a appropriate pump, thus the optimal optical gain can be obtained by regulating the average number of exciton; (3) with ultrashort pulse excitation, the auger recombination effect generated by multi-exciton state can be inhibited, increasing the probability of the stimulated emission. Finally, the optical gain of 20~dB can be reached by optimizing all of the parameters. Studies of using core/shell QD as the dopant in the liquid-core fiber and optical gain based on multi-exciton state have not yet been found in domestic and foreign research. Besides, using ultrashort pulse for exciting QD is a new method for inhibiting auger recombination effectively. This research is of great significance for the development of the QD-doped optical fiber amplifier.