Preparation method of double-cladding ytterbium-doped polarization maintaining optical fiber

Abstract

The invention discloses a preparation method of a double-cladding ytterbium-doped polarization maintaining optical fiber, and the method comprises the following steps: preparing an ytterbium-doped core rod by adopting a rare earth chelate evaporation system and MCVD, wherein the ytterbium-doped core rod comprises a core layer, an isolation layer and a cladding from inside to outside; preparing a boron-doped stress rod by adopting a plasma chemical vapor deposition process; melting the ytterbium-doped core rod into a solid rod by using a quartz sleeve at a preset temperature, thinning the solidrod to obtain an ytterbium-doped mother rod, and melting the cladding and the quartz sleeve to form a quartz cladding of the ytterbium-doped mother rod; longitudinally machining a pair of symmetricalround holes in two sides of the core layer by adopting a drill gun process, and enabling the center lines of the two round holes and the center line of the ytterbium-doped mother rod to be parallel and positioned on the same plane; enabling two boron-doped stress rods to be embedded into the two circular holes respectively to form an ytterbium-doped polarization maintaining optical fiber preform,wherein the center lines of the two boron-doped stress rods and the center line of the ytterbium-doped mother rod are located on the same plane and are equally spaced; and performing drawing to obtain the double-clad ytterbium-doped polarization maintaining optical fiber. The optical fiber prepared by the method is good in axial uniformity and beneficial to large-scale production.

Description

technical field [0001] The invention relates to the technical field of optical fiber preparation, in particular to a method for preparing a double-clad ytterbium-doped polarization-maintaining optical fiber. Background technique [0002] Ytterbium-doped fiber is a kind of active fiber. Active optical fiber refers to the doping of trace rare earth elements (such as ytterbium, erbium, etc.) Active fibers can be used to make fiber amplifiers and fiber lasers. As the gain medium of the laser, the active optical fiber can convert the pump light into laser, so as to realize the laser output of the laser. [0003] The polarization-maintaining fiber is a passive fiber. The polarization-maintaining fiber mainly uses the difference between the thermal expansion coefficient of the stress region and the doped core and cladding to generate birefringence characteristics. [0004] Limited by nonlinear effects and thermo-optic effects, the continuous increase of optical power will lead t...

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Problems solved by technology

[0006] At present, domestic ytterbium-doped polarization-maintaining optical fiber is generally prepared by MCVD liquid phase method to prepare ytterbium-doped core rod. Doping in the soot body, this doping method is easily interfered by external factors, which will lead to inconsistent longitudinal distribution of the ytterbium ion concentration of the optical rod, which will lead to the inability to guarantee the consistency of optical fiber performance

On the other hand, domestic stress rods are mainly prepared by the MCVD (modified chemical vapor deposition) process. The size of the stress rods prepared by this method is relatively small, and the core diameter is basically within 10mm, which is not conducive to the large-scale production of optical fibers.

In addition, the domestic quartz drilling method mainly adopts ultrasonic drilling. The principle of this drilling method is to repeatedly vibrate the vibration head with the cooperation of grinding powder (generally emery) and water to make the processed parts wear through. The disadvantage is that the processing depth is shallow and the processing accuracy is not high, which is suitable for processing parts below 200mm

[0007] The above disadvantages are not conducive to the large-scale production of double-clad ytterbium-doped polarization-maintaining fibers

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