High-power random fiber laser based on inclined fiber grating

Abstract

The invention relates to a high-power random fiber laser based on an inclined fiber grating. Based on special refractive index distribution of the inclined fiber grating, second-order Raman light transmitted in a fiber core is coupled into a reversely transmitted cladding mode or radiation mode, so that oscillation starting of the second-order Raman light is inhibited to break through the restriction of the generation of the second-order Raman light for laser output power. The basic composition of the high-power random fiber laser comprises a pumping source, the inclined fiber grating and a passive fiber. The high-power random fiber laser breaks through the resection of the generation of the second-order Raman light for laser output power in a traditional random fiber laser, and the output power of the random fiber laser is further improved.

Description

technical field [0001] The invention belongs to the field of fiber laser technology, and in particular relates to a high-power random fiber laser based on a tilted fiber grating. Background technique [0002] The random fiber laser uses the weak Rayleigh scattering in the long-distance passive fiber to provide random distributed feedback, and at the same time uses the nonlinear effect of stimulated Raman scattering (SRS) in the passive fiber to provide gain. Laser output under the condition of "gain fiber". Since Rayleigh scattering in disordered media is used to provide random feedback and no strict resonator structure is required, random fiber lasers have the characteristics of simple structure, no longitudinal mode, high conversion efficiency, and smooth spectrum, and are research hotspots in the field of laser technology. Early research on random fiber lasers was mainly focused on communication, sensing, imaging and other fields, and the demand for laser power was not h...

AI Technical Summary

Problems solved by technology

Theoretical studies have shown that the long-distance passive fiber in the random fiber laser structure makes the threshold of high-order Raman light lower, so when the output power reaches a certain level, the second-order Raman light will be generated quickly and the power of the first-order Raman light cannot be reached. This is currently the most important limiting factor for the increase in the output power of random fiber lasers

The generation of second-order Raman light will also reduce the light-to-light conversion efficiency of the laser

[0005] However, shortening the length of the passive fiber and introducing a "semi-open cavity" structure can only increase the output power of the laser to a certain extent. When the power reaches a certain threshold, second-order Raman light will still be generated, thereby limiting the output of the laser. power and efficiency

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