Device and method for preparing rare earth-doped optical fiber preform

Abstract

The invention discloses a device and a method for preparing a rare earth doped optical fiber. According to the preparation process, the rare earth chelate has extremely high saturated vapor pressure at about 200 DEG C, so that the complexity of equipment can be reduced, and the process is convenient to control; the flow of carrier gas He is adjusted through the MFC to control the concentration of rare earth ions, so that accurate doping is realized; by utilizing the characteristics that a co-doping agent aluminum trichloride has extremely high vapor pressure at a high temperature of 100-200 DEG C, but the aluminum trichloride is easy to absorb water vapor to deliquesce and has strong corrosivity, a pure quartz glass crucible or a pure aluminum trichloride crucible is adopted to heat and evaporate in a liner tube, and the doping amount of the aluminum trichloride is controlled by adjusting the temperature.

Description

technical field [0001] The invention belongs to the technical field of optical fiber cable preparation, and more specifically relates to a device and method for preparing rare earth-doped optical fiber. Background technique [0002] With the rapid development of fiber lasers in industrial processing, medical, aviation, military and other fields, people have put forward higher requirements for the power, beam quality, photo-darkening performance, conversion efficiency and other performance of fiber lasers. As the core component of the fiber laser, the rare earth-doped fiber acts as a laser gain medium and an optical waveguide, so the background loss, absorption coefficient, light-to-light conversion efficiency, numerical aperture, beam quality, and photo-darkening performance of the rare-earth-doped fiber directly determine the fiber The quality of the laser. [0003] Rare earth-doped optical fiber is drawn from a rare earth-doped preform. The methods for preparing rare eart...

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Problems solved by technology

However, aluminum trichloride is very easy to absorb water vapor, which is extremely corrosive to material tanks, pipes, valves, etc.; in addition, aluminum trichloride vapor has extremely high temperature requirements, and it is easy to condense and block pipes, resulting in the scrapping of preforms , causing huge economic losses

[0005] Another gas-phase doping method of rare earth chlorides is to heat and sublimate rare earth chlorides such as ytterbium trichloride in a crucible, and the chlorides of rare earth ions must be at a temperature of about 1000°C to have sufficient vapor pressure to participate in vapor phase deposition. process, and the material is prone to condensation during the transportation process, which has high requirements on the process equipment; while the co-dopant aluminum trichloride has a very high saturated vapor pressure above 200 ° C, and if it is co-sublimated with rare earth chlorides, the concentration will be extremely high. High, if an evaporation device is installed separately, the system will be extremely complicated, making it extremely difficult to control the co-mixing of the two

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