Noise-like square pulses (NLSPs) have been experimentally investigated in both normal and anomalous dispersion regimes. A chirped fiber Bragg grating (CFBG) has been employed as a dispersion management element in the compact linear-cavity mode-locked Yb-doped fiber laser. The net cavity dispersion could be switched from large anomalous dispersion (−2.71 ps ² ) to large normal dispersion (+5.33 ps ² ), depending on the direction of CFBG inserting in laser cavity. Two kinds of NLSPs with different temporal profiles are achieved in the proposed laser. In anomalous dispersion regime, the square pulse duration can be tuned from 0.91 ns to 5.39 ns, and the maximum square pulse energy is 39.57 nJ. In normal dispersion regime, the top of the pulse is flatter, the square pulse duration can be tuned from 0.89 ns to 5.97 ns, and the maximum square pulse energy is slightly higher, up to 40.17 nJ. The output laser is linearly polarized.

中文翻译：

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正常色散和异常色散状态下的类似于噪声的方波

在正常和异常色散状态下，都已经通过实验研究了类似噪声的方波脉冲（NLSP）。the光纤布拉格光栅（CFBG）已被用作紧凑型线性腔锁模掺Yb光纤激光器中的色散管理元件。净腔色散可以从大的异常色散（-2.71 ps ² ）切换到大的正常色散（+5.33 ps ² ），具体取决于CFBG插入激光腔的方向。在所提出的激光器中实现了两种具有不同时间轮廓的NLSP。在异常色散状态下，方波脉冲持续时间可以从0.91 ns调整为5.39 ns，最大方波脉冲能量为39.57 nJ。在正常色散状态下，脉冲的顶部更平坦，方波脉冲持续时间可以从0.89 ns调整到5.97 ns，并且最大方波脉冲能量稍高，最高为40.17 nJ。输出激光是线性偏振的。