色散渐减光纤环形镜的一种改进方法

提出了一种由常规光纤和色散渐减光纤构成的新的非线性光纤环形镜(NOLM)。研究了该结构的动力学特性，并与色散渐减光纤(DDF)构成的环形镜进行了比较。数值结果表明，该类型光纤环形镜能产生无基座高品质超短光脉冲，压缩脉冲的啁啾小，在脉冲中心处呈线性，而且获得的脉冲能在无损耗的常规光纤中长距离稳定传输。压缩脉冲的压缩因子和基座能量与输入脉冲的初始脉宽和峰值功率有关，当输入脉冲的宽度增加时，所需的光纤长度变长，压缩因子和基座能量有所下降；当输入功率增加时，所需光纤长度变短，压缩因子和基座能量增加。研究结果还显示，在较大的输入脉冲峰值功率范围内，当脉冲获得最佳压缩时，与色散渐减光纤环形镜相比，新的光纤环形镜所用光纤长度短，压缩因子高。

Improved Method for the Nonlinear Optical Loop Mirror Constructed from the Dispersion Decreasing Fiber

A new nonlinear optical loop mirror (NOLM) constructed from a dispersion decreasing fiber (DDF) and a normal fiber is proposed. Numerical simulation shows that a ultra-short pulse with pedestal suppression and little chirp can be generated in the new optical loop mirror and the ultra-short pulse can steadily propagate over a long lossless fiber. The compression factor and pedestal energy of the compressed pulse are related to the width and peak power of the initial pulse. The compression factor and the pedestal energy are decreasing but the optimum fiber length is increasing with the growing initial optical pulse width. In the other case, the compression factor and the pedestal energy are increasing but the required optical fiber length is decreasing with the growing input peak power. When the pulse is in optimum compression, the bigger compression factor is obtained and the optical fiber used becomes shorter comparing to the nonlinear optical loop mirror constructed from dispersion-decreasing fiber.