CN219239526U

CN219239526U - Active polarization maintaining fiber prefabricated rod assembly with fiber core doped deeply

Info

Publication number: CN219239526U
Application number: CN202223259141.4U
Authority: CN
Inventors: 徐律; 宋海瑞; 韩婷婷; 卞新海; 缪振华; 侯树虎
Original assignee: Jiangsu Fasten Optoelectronics Technology Co ltd
Current assignee: Jiangsu Fasten Optoelectronics Technology Co ltd
Priority date: 2022-12-06
Filing date: 2022-12-06
Publication date: 2023-06-23
Anticipated expiration: 2032-12-06

Abstract

The utility model relates to an active polarization maintaining optical fiber preform assembly with a deeply doped fiber core, and belongs to the technical field of optical fiber preparation. The drilling rod comprises a drilling rod, a central hole which penetrates through the center of the drilling rod up and down, stress holes are symmetrically formed in two sides of the central hole, a core rod is inserted into the central hole, and a stress rod is inserted into the stress hole. The radius of the center hole is r1,6 is less than or equal to r1 and less than or equal to 12mm, the radius of the stress hole is r2,6 is less than or equal to r2 and less than or equal to 12mm, and the distance between the center of the center hole and the center of the stress hole is d1, and 20 is less than or equal to d1 and less than or equal to 40mm. The diameters of the core rod and the stress rod are respectively 5-10 mm. The core rod comprises a core layer and a pure quartz cladding layer, and the pure quartz cladding layer is arranged on the periphery of the core layer. The core rod, the stress rod and the punching rod are independently prepared, so that the difficulty in punching is reduced, the cracking of the core rod is avoided, and the production cost is reduced; and then assembling, so that deformation of the mandrel prefabricated rod assembly in the plastic processing process is avoided, and good concentricity of the mandrel prefabricated rod assembly is kept.

Description

Active polarization maintaining fiber prefabricated rod assembly with fiber core doped deeply

Technical Field

The utility model relates to an active polarization maintaining optical fiber preform assembly with a deeply doped fiber core, and belongs to the technical field of optical fiber preparation.

Background

In recent years, with the continuous development of fiber laser technology, fiber laser technology is favored in the fields of laser medical treatment, laser radar, optical communication, weaponry, laser detection and the like, and simultaneously, higher requirements are put forward on the performance of the fiber laser, namely, the fiber laser has to maintain high power and single-mode output, has good output beam quality, and also has to output laser with polarization state so as to meet the application requirements of the high power and narrow line width fiber laser, which means that the fiber for mainly transmitting and amplifying energy in the fiber laser has better performance.

The research shows that the longer the cavity length of the fiber laser is, the more obvious the nonlinear effect of the fiber is, the Stimulated Raman Scattering (SRS) and Stimulated Brillouin Scattering (SBS) are the main nonlinear effects in the fiber laser and the amplifier, the larger the nonlinear coefficient of the rare earth doped fiber is, the length of the fiber used by the laser needs to be shortened, meanwhile, the short cavity is an important condition for realizing single longitudinal mode operation of the fiber laser, the length of the fiber laser cavity needs to be shortened, the doping concentration of the fiber core layer needs to be improved, so that the pumping absorption efficiency and the output power of the laser are improved, but the doping concentration of the fiber core layer is likely to be more difficult for the subsequent manufacturing process.

At present, the manufacturing process flow of the polarization-maintaining active optical fiber generally comprises the procedures of core rod, sleeve pipe, punching, stress rod assembly, wire drawing, testing and the like, wherein the core rod is generally prepared by adopting an MCVD method, other methods such as OVD, VAD, PCVD and the like can be adopted, after the core rod is manufactured, the manufactured core rod is inserted into the sleeve pipe with proper size through the sleeve pipe process, and is fused and contracted into an optical fiber preform rod under the high temperature effect so as to meet the designed core-cladding ratio requirement, the optical fiber preform rod after the sleeve pipe is completed is processed into the optical fiber preform rod with a stress hole by adopting a mechanical punching method, the stress rod prepared in advance is assembled on the optical fiber preform rod, and finally wire drawing coating and testing are carried out. The conventional preparation method of the polarization-maintaining active optical fiber has the following defects: firstly, in the process of sleeving the core rod, the concentricity of the optical fiber is possibly increased, and bubbles exist at the interface of the sleeving. Secondly, for the polarization-maintaining active optical fiber with high fiber core doping concentration and relatively close stress area and fiber core area, because the fiber core is deeply doped, after the traditional mode that a core rod sleeve is used for forming a mother rod is adopted, the fiber core concentration is greatly improved, so that the difficulty of punching is greatly increased, the core rod is cracked in the punching process, and the yield is low.

Disclosure of Invention

The utility model aims to solve the technical problem of providing the active polarization maintaining optical fiber preform assembly with the deeply doped fiber core aiming at the prior art, so that the difficulty of punching is reduced, the cracking of a core rod in the punching process is avoided, the yield is improved, and the production cost is reduced.

The utility model solves the problems by adopting the following technical scheme: the active polarization maintaining fiber prefabricated rod component with the fiber core deeply doped is characterized in that: the drilling machine comprises a drilling rod, a core rod and a stress rod, wherein the center of the drilling rod is provided with an axially-through center hole, stress holes are symmetrically formed in two sides of the center hole, the stress holes are axially through, the core rod is inserted into the center hole, and the stress rod is inserted into the stress hole.

The radius of the central hole is r1, the size structure satisfies that r1 is less than or equal to 6mm and less than or equal to 12mm, the radius of the stress hole is r2, the size structure satisfies that r2 is less than or equal to 6mm and less than or equal to 12mm, the distance between the center of the central hole and the center of the stress hole is d1, and the size satisfies that d1 is less than or equal to 20mm and less than or equal to 40mm.

The diameters of the core rod and the stress rod are respectively 5-10 mm, the diameter of the core rod is smaller than or equal to the inner diameter of the central hole, and the diameter of the stress rod is smaller than or equal to the inner diameter of the stress hole.

The core rod comprises a core layer and a pure quartz cladding layer, and the pure quartz cladding layer is arranged on the periphery of the core layer.

Compared with the prior art, the utility model has the advantages that: the active polarization maintaining fiber prefabricated rod component with the deeply doped fiber core is characterized in that a core rod, a stress rod and a punching rod are independently prepared, so that the punching difficulty is reduced, the core rod is prevented from cracking, and the production cost is reduced; and then assembling, so that deformation of the mandrel prefabricated rod assembly in the plastic processing process is avoided, and good concentricity of the mandrel prefabricated rod assembly is kept. The core rod, the stress rod and the punching rod can be independently and parallelly carried out, so that the production efficiency is improved, and the preparation difficulty is reduced.

Drawings

FIG. 1 is a schematic diagram of a core deep doped active polarization maintaining fiber preform assembly according to an embodiment of the present utility model;

FIG. 2 is a schematic diagram of a perforated rod in a fiber core deep doped active polarization maintaining fiber preform assembly according to an embodiment of the present utility model;

FIG. 3 is a schematic view of a core rod in a fiber core deep doped active polarization maintaining fiber preform assembly according to an embodiment of the present utility model;

FIG. 4 is a schematic view of refractive index profile of a core rod;

in the figure, a core rod 1, a core layer 1.1, a pure quartz cladding layer 1.2, a 2 stress rod, a 3 punching rod, a 3.1 central hole and a 3.2 stress hole are shown.

Detailed Description

The utility model is described in further detail below with reference to the embodiments of the drawings.

As shown in fig. 1 and 2, an active polarization maintaining optical fiber preform assembly with deep doped fiber core in this embodiment includes a punching rod, a central hole penetrating up and down is formed in the center of the punching rod, stress holes penetrating up and down are symmetrically formed on two sides of the central hole, a core rod is inserted into the central hole, and a stress rod is inserted into the stress holes. The radius of the center hole is r1,6 r1 r 12mm, and the radius of the stress hole is r2,6 r2 r 12mm. The diameters of the core rod and the stress rod are respectively 5-10 mm. The distance between the center of the center hole and the center of any stress hole is d1, and d1 is smaller than or equal to 20 and smaller than or equal to 40mm.

As shown in fig. 3, the core rod includes a core layer and a pure quartz cladding layer provided outside the core layer.

A preparation method of a polarization-preserving active optical fiber with a deeply doped fiber core comprises the following specific steps:

(1) And selecting a quartz base pipe, and carrying out pickling and preheating pretreatment on the quartz base pipe, so that impurities and bubbles on the inner wall of the quartz base pipe can be effectively eliminated. Preferably, the pickling solution comprises 90% hydrofluoric acid solution and 10% nitric acid mixed solution; preferably, the preheating temperature is 800-1000 ℃ and the preheating time is 5-10 min.

(2) The core rod is prepared by MCVD process, or other methods such as OVD, VAD and PCVD, etc., the refractive index profile of the core rod is shown in figure 4, the diameter of the core layer is 1-3mm, the main component of the core layer is pure quartz, and the homogeneous doping design is adopted, wherein SiO is adopted ₂ The mol percentage of Yb is 80-90 ₂ O ₃ The mole percentage of Al is 0.3-0.6 ₂ O ₃ The mole percentage of P is 1-6 ₂ O ₅ The mole percentage is 1-5. Wherein FIG. 4 is a schematic view of refractive index profile of the core rod, and the refractive index difference of the core layer relative to the pure quartz cladding layer is delta n, which is 2.0 percent-delta n-4.0 percent.

(3) The preparation of stress bars is carried out by MCVD technology, other methods such as OVD, VAD, PCVD and the like can also be selected. Preferably, the stress area of the stress bar has a diameter of 4-8mm, and the material composition of the stress area is SiO ₂ 、GeO ₂ 、B ₂ O ₃ Adopts a homogeneous doping design, wherein SiO ₂ The mol percentage of GeO is 64-80 ₂ The mole percentage of B is 0.1-2 ₂ O ₃ The mole percentage is 20-35; the relative refractive index difference delta 3 between the stress region and the pure quartz glass is between-0.5% and-2.0%.

(4) Carrying out external grinding processing on the core rod and the stress rod, so that the size of the core rod is controlled to be 5mm-10mm; the size of the stress rod is controlled between 5mm and 10mm.

(5) Selecting a punching rod with a proper size, carrying out center hole processing on the punching rod by a punching lathe, wherein the radius of the center hole is r1, r1 is less than or equal to 6 and less than or equal to 12mm, then punching two stress holes, the radius of each stress hole is r2, r2 is less than or equal to 6 and less than or equal to 12mm, and the distance from the center of each stress hole to the center of the center hole is d1, and d1 is less than or equal to 20mm and less than or equal to 40mm.

(5) And respectively inserting the two stress rods and the core rod which are prepared in advance into corresponding holes of the punching rod, wherein the two stress rods are symmetrically distributed relative to the core rod, and the two stress rods and the core rod are combined into the optical fiber preform assembly.

(6) And (3) placing the optical fiber preform assembly into a drawing furnace for melting, drawing, coating and winding to form the polarization-preserving active optical fiber with the deeply doped fiber core.

The core rod, the stress rod and the punching rod are independently prepared, so that the difficulty in punching is reduced, the cracking of the core rod is avoided, and the production cost is reduced; and then assembling, so that deformation of the mandrel prefabricated rod assembly in the plastic processing process is avoided, and good concentricity of the mandrel prefabricated rod assembly is kept. The core rod, the stress rod and the punching rod can be independently and parallelly carried out, so that the production efficiency is improved, and the preparation difficulty is reduced. The core rod, the stress rod and the punching rod are independently prepared, so that the size adaptability is higher, and the size of the optical fiber preform assembly can be flexibly controlled.

In addition to the above embodiments, the present utility model also includes other embodiments, and all technical solutions that are formed by equivalent transformation or equivalent substitution should fall within the protection scope of the claims of the present utility model.

Claims

1. The active polarization maintaining fiber prefabricated rod component with the fiber core deeply doped is characterized in that: the drilling machine comprises a drilling rod, a core rod and a stress rod, wherein the center of the drilling rod is provided with an axially-through center hole, stress holes are symmetrically formed in two sides of the center hole, the stress holes are axially through, the core rod is inserted into the center hole, and the stress rod is inserted into the stress hole.

2. The core deep doped active polarization maintaining fiber preform assembly of claim 1, wherein: the radius of the central hole is r1, the size structure satisfies that r1 is less than or equal to 6mm and less than or equal to 12mm, the radius of the stress hole is r2, the size structure satisfies that r2 is less than or equal to 6mm and less than or equal to 12mm, the distance between the center of the central hole and the center of the stress hole is d1, and the size satisfies that d1 is less than or equal to 20mm and less than or equal to 40mm.

3. The core deep doped active polarization maintaining fiber preform assembly of claim 1, wherein: the diameters of the core rod and the stress rod are respectively 5-10 mm, the diameter of the core rod is smaller than or equal to the inner diameter of the central hole, and the diameter of the stress rod is smaller than or equal to the inner diameter of the stress hole.

4. The core deep doped active polarization maintaining fiber preform assembly of claim 1, wherein: the core rod comprises a core layer and a pure quartz cladding layer, and the pure quartz cladding layer is arranged on the periphery of the core layer.