双包层光纤激光器的输出性能及稳定性与包层光的滤除程度有关。光纤激光器输出光中的剩余抽运光不仅会影响到输出光的单色性，还会对输出设备造成损害，甚至破坏光学器件。通常在内包层外涂一种高折射的导光胶来滤除包层光，但此方法使包层光在较短的长度内被大量地滤除，导致热沉上功率密度较高，给散热带来较大的压力。实验中采用3种不同折射率的导光胶，分步滤除包层光，减小局部温度过高。采用Zemax和Matlab软件研究了此滤除方式的特点，搭建了验证实验系统。实验结果表明，输出激光中的包层光已被滤除，滤除效果可达到20 dB，且热量分布均匀，不会引起局部温度过高。

The output performance and stability of double-cladding all-fiber laser are both affected by the ability of stripping cladding light. The removing pump light will influence the monochromaticity and beam quality of fiber laser, cause damage to the output device and even damage optical device. The common method is recoating the double-cladding fiber (DCF) with a high index gel, which strips the cladding light quickly within the first few millimeters and makes the heat locally concentrated. A method using a group of gels to strip the cladding light is adopted. The commercial software Zemax and Matlab are used to simulate the stripping progress of cladding light, and an experimental verification system is presented. The results indicate that the proposed method can strip the cladding light gradually over the length of the fiber with an attenuation ability of 20 dB, and the thermal distribute is uniform without local temperature too high.