A rare earth uniformly doped optical fiber preform core rod and its preparation method

Abstract

The invention relates to a rare-earth uniformly-doped fiber perform core rod and a preparation method thereof. The core rod adopts silicon dioxide used as a matrix and is at least doped with a rare earth ion and a co-doping ion, wherein the doping concentration of the rare earth element is calculated in the oxide form; the concentration of the doped rare earth oxide is 0.05-0.5mol%; the co-doping ion is at least one of Al and P elements; the co-doping agent concentration is calculated in the oxide form; and the concentration of the co-doping agent oxide is 0.4-10mol%. The core rod is prepared by adopting a powder forming-sintering method. The core rod disclosed by the invention has the advantages that the fiber core has high doping uniformity in the axial direction and the radial direction; the refractive index profile of the fiber core has high flatness; the numerical aperture (NA) of the fiber core is accurate and adjustable; and the optical fiber has high slope efficiency. Based on the rare earth doped core rod, various rare-earth doped optical fibers with different structures can be manufactured by using a core rod through the external cladding technology, i.e., the manufacturing requirements of rare earth doped optical fibers with different structures such as single cladding single mode, double cladding single mode, polarization-maintaining double cladding, large-mode field area air hole double cladding and the like are satisfied.

Description

technical field [0001] The invention relates to a rare earth uniformly doped optical fiber preform core rod and a preparation method thereof, belonging to the technical field of optical fiber manufacturing. Background technique [0002] As early as the early 1970s, people began to study rare earth-doped silica optical fibers (Appl. Phys. Lett., 1973, 23(7): 388-389). Optical fiber preparation technology generally includes preform rod preparation technology and optical fiber design and implementation technology. The same is true for rare earth doped fibers. However, since the rare earth-doped optical fiber has a wide range of application fields, and the functions and application requirements are also different, the preparation of the rare earth-doped optical fiber is more complicated than that. In terms of preform technology, the MCVD method is widely used. In terms of rare earth doping technology, based on the MCVD process, the doping technology includes high-temperature ...

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Problems solved by technology

[0006] In summary, there are still a series of problems in the commonly used rare earth-doped optical fiber technology. The preform rod technology based on the MCVD method has the problem of inhomogeneity in the radial or axial direction of the preform rod, which cannot meet the requirements of one-rod multi-fiber design and The requirements of optical fiber realization technology; Yb-doped bulk materials prepared by sintering method have not yet successfully realized the preparation of Yb-doped optical fibers with single-mode characteristics, good bending properties, and high laser slope efficiency; prepared by powder sintering method. Yb body material, outer cladding technology and rare earth doped optical fiber technology other than fluorine-doped cladding have not been realized

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