2 [um] waveband random optical fiber laser device based on inclined optical fiber grating

Abstract

The invention discloses a 2 [um] waveband random optical fiber laser device based on an inclined optical fiber grating, and belongs to the technical field of optical fiber laser devices. The 2 [um] waveband random optical fiber laser device is composed of a pumping source, an optical fiber combiner, an optical isolator, a wavelength division multiplexer, an optical circulator, a first double-cladding thulium-doped optical fiber, a second double-cladding thulium-doped optical fiber and an inclined optical fiber grating inscribed on the second double-cladding thulium-doped optical fiber. According to the invention, the thulium-doped optical fiber is used for providing optical gain, the inclined optical fiber grating is etched on the second double-cladding thulium-doped optical fiber, the second-order Raman light oscillation starting is restrained by using the special refractive index distribution of the inclined optical fiber grating, and the generated random laser is output through thesecond double-cladding thulium-doped optical fiber inscribed with the inclined optical fiber grating; and the 2 [um] waveband random optical fiber laser device has the advantages of being high in conversion efficiency and output power and capable of acquiring specific-wavelength random laser output.

Description

technical field [0001] The invention belongs to the technical field of fiber lasers, and in particular relates to a 2um band random fiber laser based on a tilted fiber grating. Background technique [0002] Random fiber laser is a new type of fiber laser developed in recent years, which uses Rayleigh scattering in the fiber to provide random feedback without a fixed optical cavity. Random fiber laser has the characteristics of simple structure, no longitudinal film, and smooth spectrum, and is a research hotspot in the field of laser technology. In recent years, with the improvement of pumping capacity and continuous optimization of laser parameters, random fiber lasers have achieved power output of hundreds of watts, and are expected to become a new type of high-power fiber light source. [0003] In the early research process, the length of the passive fiber in the random fiber laser is generally more than several kilometers to ensure sufficient distributed feedback. Theo...

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Problems solved by technology

Theoretical studies have shown that the long-distance doped fiber in the random fiber laser structure makes the threshold of high-order Raman light lower, so after the output power reaches a certain level, the second-order Raman light will be generated quickly and lead to the first-order Raman light power. It cannot be improved, which is the main limiting factor for increasing the output power of random fiber lasers

In order to achieve higher power output, the method of shortening the length of the fiber is used to increase the generation threshold of second-order Raman light. However, shortening the length of the doped fiber can only increase the output power of the laser to a certain extent. When the power reaches a certain threshold , will still produce second-order Raman light, which will limit the output power and efficiency of the laser and increase the difficulty of high-power output

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