Xu Jiangtao, Wang Longtao, Zhang Longkun, Teng Linping, Zhang Zhengwei, Berko Richard Roy, Zhang Liang, Pang Fufei, Zeng Xianglong
Opt Express. 2021 Oct 11;29(21):34109-34117. doi: 10.1364/OE.434479.
We experimentally investigate two schemes of Brillouin random fiber laser (RFL) by using high-order-mode (HOM) pump in a few-mode fiber (FMF). The core-mode conversion between LP and LP modes is obtained in the FMF by cascading long period fiber gratings (LPFG) working at the same wavelength region. Different transversal modes of stimulated Brillouin scattering (SBS) can be implemented based on broadband long period fiber gratings (LPFG) and acoustically induced fiber gratings (AIFG). The RFL base on two broadband LPFGs can obtain high purity LP mode operating in the range of 1543 nm to 1565 nm. Moreover, the output mode can be dynamically switched between LP mode, LP mode and LP mode by modulating frequency shift keying (FSK) signal of the AIFG. This work has potential application prospects in the fields of mode division multiplexing systems, speckle-free imaging, free-space optical communication, laser material processing.
我们通过在少模光纤（FMF）中使用高阶模（HOM）泵浦，对布里渊随机光纤激光器（RFL）的两种方案进行了实验研究。通过级联工作在相同波长区域的长周期光纤光栅（LPFG），在FMF中实现了LP模式与LP模式之间的纤芯模式转换。基于宽带长周期光纤光栅（LPFG）和声致光纤光栅（AIFG），可以实现受激布里渊散射（SBS）的不同横向模式。基于两个宽带LPFG的RFL可以获得在1543nm至1565nm范围内工作的高纯度LP模式。此外，通过调制AIFG的频移键控（FSK）信号，可以在LP模式、LP模式和LP模式之间动态切换输出模式。这项工作在模式分割复用系统、无散斑成像、自由空间光通信、激光材料加工等领域具有潜在的应用前景。
