In this work, we experimentally investigate the dependence of the stimulated Raman scattering (SRS) effect on the seed linewidth of a high-power nanosecond superfluorescent fiber source (ns-SFS). The results reveal that the SRS in the ns-SFS amplifier is significantly influenced by the full width at half maximum (FWHM) of the ns-SFS seed, and there is an optimal FWHM linewidth of 2 nm to achieve the lowest SRS in our case. The first-order SRS power ratio increases rapidly when the seed’s linewidth deviates from the optimal FWHM linewidth. By power scaling the ns-SFS seed with the optimal FWHM linewidth, a narrowband all-fiberized ns-SFS amplifier is achieved with a maximum average power of 602 W, pulse energy of 24.1 mJ and corresponding peak power of 422.5 kW. This is the highest average power and pulse energy achieved for all-fiberized ns-SFS amplifiers to the best of our knowledge.

中红外超荧光光源具有光谱范围宽、空间相干性好、时域稳定性高等特点，应用前景广泛，但受限于中红外侧面泵浦合束器，目前普遍利用空间结构泵浦产生。文中根据拉锥光纤侧面耦合的原理，在125 μm包层直径的无源双包层氟化物光纤上实现了中红外光纤侧面泵浦合束器的研制，该合束器泵浦光耦合效率达82.3%，可承受的最大泵浦功率达87.5 W。通过在中红外增益光纤上制得侧面泵浦合束器，实现了全光纤中红外超荧光光源产生，前后向输出的中红外超荧光最高功率和为91.09 mW （后向输出53.67 mW，前向输出37.42 mW），输出光谱范围从2702 nm覆盖至2830 nm。在中红外超荧光总输出功率为33.03 mW时，获得了108 nm的最宽20 dB带宽。文中实现的中红外全光纤超荧光光源克服了以往空间泵浦复杂度高、调节难的问题，对推动中红外超荧光光源的进一步功率放大具有重要意义。

近1 μm波段的可调谐光纤光源在光纤传感、激光冷却、光化学、光谱学以及医疗等领域具有广泛应用，近年来成为光纤光源领域的一个研究热点。本文首先系统回顾了能够实现波长调谐的4类光纤光源的发展历程，然后分析了它们存在的问题及可能的解决思路，最后对近1 μm波段可调谐光纤光源进行了总结和展望。

High power superfluorescent fiber sources (SFSs), which could find wide applications in many fields such as middle infrared laser generation, Raman fiber laser pumping and spectral beam combination, have experienced a flourishing time in recent years for its unique properties, such as short coherence length and high temporal stability. The challenge for performance scalability of powerful SFS mainly lies on the physical issues including parasitic laser oscillation and modal instability (MI). In this contribution, by employing in-band pumping avenue and high-order transverse-mode management, we explore a high power SFS with record power, near-diffraction-limited beam quality and spectral manipulation flexibility. An ultimate output power of 3.14 kW can be obtained with high temporal stability and a beam quality of for the amplified light. Furthermore, the dynamics of spectral evolutions, including red-shifting of central wavelength and unsymmetrical broadening in spectral wings, of the main amplifier with different seed linewidths are investigated contrastively. Benefiting from the unique high pump brightness and high MI threshold of in-band pumping scheme, the demonstrated system also manifests promising performance scaling potential.