AI 中文总结
本研究证明增益管理非线性放大机制可在有限增益带宽光纤中产生稳定高峰值功率相似子，实现能量十倍提升，推动高能超短脉冲激光技术发展。
AI 中文摘要
光纤激光器和放大器为传统固态系统提供了有吸引力的替代方案。然而，由于脉冲限制在小型光纤纤芯内而产生的多种非线性效应的复杂相互作用，以及可用有源光纤的增益带宽所施加的限制，在光纤中产生高能超短激光脉冲面临挑战。在具有正常色散的光纤中，自相似放大和增益管理非线性放大（GMNA）脉冲传播机制的发现表明，这些挑战可以转化为优势。在这里，我们表明，在GMNA机制中产生的脉冲实际上是在具有有限增益带宽的现实光纤中理想化相似子型脉冲的实现。我们的解析和数值结果展示了如何根据传播长度塑造光纤增益，以实现具有稳定增加能量的恒定峰值功率相似子样脉冲，脉冲带宽超过增益带宽，以及近乎线性的频率啁啾，从而允许高效压缩脉冲至其傅里叶极限。在没有拉曼非线性的情况下，这些脉冲在标准单模光纤中可达到微焦耳级能量，与目前最好的非线性放大器相比，脉冲能量增加了十倍。我们的结果对非线性波动力学的基本理解以及光纤激光技术的进步具有重要意义，支持在微加工、计量学和生物成像等领域可靠地产生高能脉冲以供实际使用。
英文摘要
Fiber lasers and amplifiers offer attractive alternatives to conventional solid-state systems. However, generation of high-energy ultrashort laser pulses in fibers faces challenges due to the complex interplay of multiple nonlinear effects arising due to pulse confinement within a small fiber core and also limitations imposed by the gain bandwidth of the available active fibers. The discovery of self-similar amplification and gain-managed nonlinear amplification (GMNA) pulse propagation regimes in fibers with normal dispersion suggests that these challenges can be turned into an advantage. Here we show that pulses generated in the GMNA regime are, in fact, the realization of the idealized similariton-type pulses in realistic fibers with limited gain bandwidth. Our analytical and numerical results show how one should shape the fiber gain as a function of propagation length to achieve constant peak power similariton-like pulses with steadily increasing energy, the pulse bandwidth exceeding the gain bandwidth, and the nearly linear frequency chirp allowing for efficient pulse compression to its Fourier limit. Absent Raman nonlinearities, these pulses can reach $μ$J level energies in standard single-mode fibers, representing a tenfold increase in pulse energy compared to the best currently available nonlinear amplifiers. Our results have significant implications for the fundamental understanding of nonlinear wave dynamics and for the advancement of fiber laser technology, supporting the reliable generation of high-energy pulses for practical use in areas such as micromachining, metrology, and bioimaging.
