Shangguang broke through the technical bottleneck of high-power Raman fiber laser

Recently, the Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences broke through the technical bottleneck
of high-power Raman fiber laser research.
This research has been supported
by the Hundred Talents Program of the Chinese Academy of Sciences, the National "863" Program, the National Natural Science Foundation of China and other projects.

The expert research group of the Institute of Optics proposed a ytterbium-Raman integrated fiber amplifier structure, which effectively broke through the main technical bottleneck of Raman fiber laser power improvement, and obtained 580W single-mode linear polarized Raman fiber laser and 1.
3kW near-single-mode Raman fiber laser output
for the first time at 1120nm wavelength.

In recent years, high-power fiber lasers have developed rapidly
.
Ytterbium-doped fiber lasers in the 1mm band have near-diffraction-limited output power of up to 20kW and multi-transverse mode output power of up to 100kW
.
Nevertheless, the output wavelength of rare earth doped fiber lasers, due to the limitation of rare earth ion energy level transitions, can only cover a limited spectral range, which limits its application fields
.
Raman fiber lasers based on the stimulated Raman scattering effect in optical fibers are an effective means
to expand the wavelength range of fiber lasers.

In this study, two or more wavelengths of seed laser are injected into a general high-power ytterbium-doped fiber amplifier, and the wavelength interval corresponds to the Raman frequency shift of the fiber
.
The seed laser at the center of the ytterbium gain bandwidth is amplified first, and the Ramanstox laser is stepwise amplified
as a pump laser in the subsequent fiber.
The preliminary demonstration experiment obtained a 300 W 1120nm Raman fiber laser output.
Then, a single-transverse mode line-polarized Raman fiber laser of 580W and a near-single-mode Raman fiber laser
output of 1.
3kW were obtained using a larger cladding (400mm) fiber.
In view of the fact that the current high-power ytterbium-doped fiber lasers adopt the main oscillation amplification structure, the newly proposed fiber amplifier structure can be used to further improve the output power
of Raman fiber lasers.
Preliminary numerical calculations also show that this technical method is expected to obtain kilowatt-level laser output
at any wavelength in the range of 1~2mm.