Optical temporal soliton generation in optical fibers and resonators has achieved great breakthroughs and found significant applications in many fields. Despite recent advances on optical soliton generation in optical fibers, it remains challenging to realize a shower of Raman solitons at a certain wavelength in optical fibers, i.e. put all the generated Raman solitons at a same wavelength on demand. Here we propose and experimentally demonstrate a shower of mid-infrared Raman solitons at designed wavelength of 3 μm from a tapered fluorotellurite fiber pumped by a 1960 nm picosecond fiber laser. Tapered fluorotellurite fibers have an untapered region length of ∼49 cm and a tapered transition region length of ∼1 cm. The fiber segment at the end of the tapered region has a 2nd zero-dispersion wavelength of ∼3 μm. Firstly, multiple Raman solitons with different wavelengths are generated in the untapered region pumped by the 1960 nm picosecond laser. Then, as Raman solitons propagate into the tapered region, the redshift of all the generated Raman solitons with different wavelengths are accelerated due to the dramatic increase of the nonlinear coefficient. Finally, as Raman solitons move out from the tapered region, all the accelerated Raman solitons are stopped around 3 μm owing to the occurrence of soliton self-frequency shift cancellation, causing the generation of a shower of mid-infrared Raman solitons around 3 μm. This phenomenon may find applications in super-efficient nonlinear light generation and signal processing.

光纤和谐振器中的光学时间孤子产生取得了重大突破，并在许多领域得到了重要应用。尽管最近在光纤中产生光学孤子方面取得了进展，但在光纤中实现特定波长的拉曼孤子的淋浴仍然具有挑战性，即将所有生成的拉曼孤子按需置于同一波长。在这里，我们提出并通过实验证明了由 1960 nm 皮秒光纤激光器泵浦的锥形氟碲酸盐光纤在设计波长为 3 μm 时的中红外拉曼孤子簇射。锥形氟碲酸盐纤维的非锥形区长度约为 49 cm，锥形过渡区长度约为 1 cm。锥形区域末端的光纤段的第二零色散波长约为 3微米。首先，在由 1960 nm 皮秒激光器泵浦的非锥形区域中产生多个不同波长的拉曼孤子。然后，随着拉曼孤子传播到锥形区域，所有产生的不同波长的拉曼孤子的红移由于非线性系数的急剧增加而加速。最后，如拉曼孤子从锥形区域移出，所有的加速拉曼孤子围绕3停止μ米由于孤子自频移抵消的发生，导致大约3中红外拉曼孤子的淋浴的产生μ米。这种现象可能会在超高效非线性光生成和信号处理中找到应用。