Annular backward pumping structure of high-power all-fiber laser

Abstract

The invention discloses an annular backward pumping structure of a high-power all-fiber laser. The annular backward pumping structure comprises a semiconductor laser pumping source with fiber pigtails, a beam combiner, a low-reflectivity fiber Bragg grating, a gain fiber, a high-reflectivity fiber Bragg grating and a beam splitter, wherein the beam combiner is an (n+1)x1 beam combiner and comprises n pumping light input fibers and a central main fiber; the beam splitter splits a beam into m paths; the fiber pigtails of (n-m) semiconductor lasers of the pumping source are connected with (n-m) input fibers of the beam combiner; an output end of the beam combiner is connected with an input end of the beam combiner through the low-reflectivity fiber Bragg grating, the gain fiber and the high-reflectivity fiber Bragg grating; and m output fibers of the beam combiner are connected with m input fibers of the beam combiner. By adoption of the annular backward pumping structure of the high-power all-fiber laser, the pumping light utilization rate of the conventional backward pumping structure of a high-power fiber laser can be effectively improved.

Description

technical field [0001] The invention relates to an all-fiber laser, in particular to an annular reverse pumping structure of a high-power all-fiber laser. technical background [0002] The original high-power all-fiber laser reverse pumping structure such as figure 2 As shown, it consists of a semiconductor laser pump source 201 with a pigtail, a beam combiner 202, a low inverse Bragg fiber grating 203, a doped double-clad gain fiber 204, a high inverse fiber Bragg grating 205, and a light-absorbing heat sink 206. [0003] The laser light is output from the low inverse Bragg fiber grating, and its direction through the beam combiner is opposite to that of the pump light entering the beam combiner. The pump light passes through the low-inverse fiber Bragg grating, doped double-clad gain fiber, and high-inverse fiber Bragg grating in one pass, and the remaining pump light that is not absorbed is output through the high-inverse fiber Bragg grating, which is opposite to the out...

AI Technical Summary

Problems solved by technology

[0004] In specific experiments, it was found that for high-power applications, considerable residual pump light will be generated. Even if the absorption coefficient and length of the doped double-clad gain fiber are increased to improve the absorption of the residual pump light, it still cannot meet the requirements. Specific application requirements, and the thermal effect will be more obvious if the absorption coefficient is too high. If the gain fiber is too long, the cost of the fiber will increase, the coil space will increase, and nonlinear effects will easily occur in narrow linewidth applications.

For the remaining pump light of tens of watts, at present, a light-absorbing heat-dissipating device or even a cooling device is usually specially installed, which increases energy consumption and has hidden dangers

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