Rare-earth-doped optical fiber with optimized background loss and preparation method of rare-earth-doped optical fiber

Abstract

The invention provides a back-to-bottom loss optimized rare earth doped optical fiber, which comprises a core layer, a transition cladding and a pure silicon cladding which are sequentially arranged from inside to outside, and is characterized in that the core layer and the transition cladding are both multi-element doped silicon dioxide layers; doped materials in the core layer comprise aluminum, ytterbium, phosphorus and one or more alkali metal elements; the doping concentration of the alkali metal element is calculated according to the oxide form of the alkali metal element, and the average concentration of the alkali metal oxide doped in the core layer is 50ppm-1000ppm; doped materials in the transition cladding comprise fluorine, phosphorus and one or more alkali metal elements; the doping concentration of the alkali metal element is calculated according to the oxide form of the alkali metal element, and the average concentration of the alkali metal element doped in the transition cladding is 500 ppm to 300 ppm; wherein alkali metal elements doped in the core layer and the transition cladding are the same. According to the invention, the core layer and the transition cladding can form good viscosity matching through the doping of the alkali metal, thereby reducing the defects and stress loss in the preparation of the optical fiber, and further optimizing the back bottom loss of the rare earth-doped optical fiber.

Description

technical field [0001] The invention relates to the field of optical fiber technology, in particular to a rare earth-doped optical fiber with optimized background loss and a preparation method thereof. Background technique [0002] With the rapid development of optical fiber communication technology, the use of optical fiber is becoming more and more extensive. The overall situation is prosperous, in which optical fibers are not only widely used in conventional communication fields, but also in consumer electronics, material processing and other industries. Active rare earth doped fiber can not only be used as the key raw material in fiber laser, but also can be used in the production of optical fiber communication devices such as optical amplifiers, wavelength conversion and other optical fiber devices. [0003] At present, the mainstream preparation method of rare earth doped preform is modified chemical vapor phase method (MCVD). Most of the research institutions and ent...

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Problems solved by technology

[0005] Aiming at the above defects or improvement needs of the prior art, the present invention provides a rare earth-doped optical fiber and its preparation method, which can be effectively used in the preparation of optical fiber preforms by using a rare earth halide evaporation system and a plasma vapor deposition (PCVD) process. Alkali metal doping is carried out during the process, and the same alkali metal element doping is set in the core layer and the transition cladding layer; thereby improving the viscosity matching between the cladding layer and the core layer of the preform and reducing the viscosity difference during the preparation process The stress defect generated reduces the core back-to-bottom loss of the fiber

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