Active optical fiber structure for gaining application and achieving method thereof

Abstract

The invention relates to fiber lasers, provides an active optical fiber structure for gaining an application and an achieving method thereof, so that a quite high coupling efficiency of fiber cores to covering pump lights can be achieved even though an internal covering is not needed to be designed into a polygon structure such as an octagon or a D-type. The structured is characterized by comprising a fiber core, a quartz covering, a low-refractive-index cladding and an external cladding which form a concentric circular layer structure from inside to outside, wherein the quartz covering can be formed either by only one layer of quartz covering with a graded refractive index or by a layer of internal quartz covering with a graded refractive index and a layer of external quartz covering, while the refractive indexes at any position of the internal quartz covering are all higher than the refractive index of the external quartz covering. According to the structure and the method, the problems of high welding loss, high bending loss, low strength and the like of the active optical fiber in the prior art are solved, the production process for the active optical fiber is simplified, and significance is provided for fiber lasers.

Description

technical field [0001] The present invention relates to fiber lasers, and more particularly to active fibers used in fiber lasers to efficiently couple pump radiation into the fiber gain core. The optical fiber structure can be used in the manufacture of optical fiber couplers, optical fiber gratings, optical fiber isolators and passive optical fibers for energy transmission. technical background [0002] Fiber laser refers to a laser that uses optical fiber as the laser medium. By doping rare earth ions in the fiber core, such as Yb, Er, Tm, Ho, etc., the laser gain output of the corresponding wavelength is obtained. Compared with traditional solid-state lasers, fiber lasers have the advantages of good heat dissipation, high conversion efficiency, and good beam quality. [0003] For conventional single-mode fiber lasers, the pump light injected into the fiber core must be single-mode, which limits the efficiency of the pump light into the fiber, resulting in low output pow...

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Problems solved by technology

[0005] In the prior art, although the method of designing a polygonal inner cladding structure with a different shape can improve the pumping efficiency of the double-clad fiber, it also has many shortcomings.

Such a structural design requires optical processing of the quartz optical fiber preform, and due to the influence of stress on the quartz material, it is very easy to crack during optical processing and polishing, resulting in a very low production rate; and due to the polishing of the surface of the preform treatment, it is easy to cause the surface to be unclean, and impurity particles such as polishing powder and corundum are introduced, resulting in an increase in fiber loss; because the shape of the quartz cladding of the double-clad fiber is irregular and polygonal, the strength and bending resistance of the fiber are greatly reduced ; The special-shaped polygonal cladding structure also causes the improvement of the optical fiber fusion splicing loss

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