阅读说明：本技术 一种光纤预制棒制造设备 (Optical fiber perform manufacture equipment ) 是由 刘旋 郭浩 喻煌 岳静 谢校臻 于 2020-11-13 设计创作，主要内容包括：本发明涉及光纤预制棒生产技术领域,具体涉及一种光纤预制棒制造设备,该光纤预制棒制造设备,包括：密封机构,其包括间隔设置的进气端密封件和出气端密封件,用于密封反应管的两端；还包括微波谐振腔,其用于套设在所述反应管的外侧,并可沿所述反应管的轴向方向往复运动；还包括进气管,其包括用于伸入所述反应管的出气端,所述进气管穿过进气端密封件,且所述出气端被配置为在所述反应管内与所述谐振腔同步往复运动。本发明能够解决现有技术中反应管内的反应物在每个沉积点的反应浓度不一致,会导致光棒在轴向上不均匀的问题。(The invention relates to the technical field of optical fiber perform production, in particular to an optical fiber perform manufacturing device, which comprises: the sealing mechanism comprises a gas inlet end sealing element and a gas outlet end sealing element which are arranged at intervals and used for sealing two ends of the reaction tube; the microwave resonant cavity is sleeved outside the reaction tube and can reciprocate along the axial direction of the reaction tube; the gas inlet pipe comprises a gas outlet end used for extending into the reaction pipe, the gas inlet pipe penetrates through the gas inlet end sealing piece, and the gas outlet end is configured to synchronously reciprocate with the resonant cavity in the reaction pipe. The invention can solve the problem that the reaction concentration of reactants in the reaction tube at each deposition point is inconsistent in the prior art, which can cause the optical rod to be nonuniform in the axial direction.)

1. An optical fiber preform manufacturing apparatus, comprising:

the sealing mechanism comprises a gas inlet end sealing piece (11) and a gas outlet end sealing piece (12) which are arranged at intervals and are used for respectively sealing two ends of the reaction tube (2);

the resonant cavity (3) is sleeved on the outer side of the reaction tube (2) and can reciprocate along the axial direction of the reaction tube (2);

an inlet pipe (4) comprising an outlet end for extending into the reaction tube (2), the inlet pipe (4) passing through an inlet end seal (11) and the outlet end being configured to reciprocate within the reaction tube (2) in synchronism with the resonant cavity (3).

2. An optical fiber preform fabricating apparatus according to claim 1, wherein: the air inlet pipe sealing structure is characterized by further comprising a telescopic mechanism (5) which is arranged on the air inlet pipe (4) in a sleeved mode, one end of the telescopic mechanism is connected with the air inlet end sealing element (11) in a sealing mode, the other end of the telescopic mechanism is connected with the air outlet end in a sealing mode, and the telescopic mechanism (5) can stretch along with the reciprocating motion of the air inlet pipe (4) synchronously.

3. An optical fiber preform fabricating apparatus according to claim 2, wherein the telescopic mechanism (5) comprises:

the isolating pipe (52) is sleeved on the air inlet pipe (4), one end of the isolating pipe is connected with the air outlet end in a sealing mode, and the isolating pipe reciprocates along with the air outlet end;

the telescopic unit (51) is sleeved on the air inlet pipe (4), two ends of the telescopic unit are respectively connected with the isolation pipe (52) and the air inlet end sealing element (11), and the telescopic unit (51) can synchronously stretch along with the reciprocating motion of the isolation pipe (52).

4. An apparatus for manufacturing an optical fiber preform according to claim 1, wherein the outlet of the gas inlet tube (4) is provided with a metal microwave isolation mesh (41).

5. An apparatus for fabricating an optical fiber preform according to claim 1, further comprising a holding furnace (6) for being fitted over the outside of the reaction tube (2) and the resonance chamber (3).

6. An apparatus for manufacturing an optical fiber preform according to claim 5, wherein the holding furnace (6) includes three front, middle and rear temperature-controllable sections.

7. An apparatus for manufacturing an optical fiber preform according to claim 6, wherein temperature sensors are provided in the temperature controllable sections of the front, middle and rear sections of the holding furnace (6).

8. An optical fiber preform fabricating apparatus according to claim 1, further comprising a negative pressure pumping means for connecting to the outlet of said reaction tube (2) to maintain a constant pressure in the reaction tube (2).

9. An apparatus for manufacturing an optical fiber preform according to claim 1, further comprising a movable stage (7) connected to said resonant cavity (3) for driving said resonant cavity (3) to reciprocate.

10. An apparatus for fabricating an optical fiber preform according to claim 1, further comprising a driving motor connected to the gas inlet tube (4) for driving the gas inlet tube (4) to reciprocate.

Technical Field

The invention relates to the technical field of optical fiber perform production, in particular to optical fiber perform manufacturing equipment.

Background

In recent years, with the large-scale deployment of 4G and the commercialization of 5G, the progress of digitization is rapidly advancing, and the demand of people for data transmission is increasing. Meanwhile, optical communication fibers have been attracting attention as the most important component in data transmission.

The PCVD plasma chemical vapor deposition process, which is currently the most common method for fabricating communication optical fibers, deposits thousands of deposited layers, and is thus very accurate in waveguide structure design and material composition and structure design. The method has the characteristics of high-precision refractive index distribution control, high deposition efficiency, excellent flexibility and the like. The PCVD process can not only produce high-quality multimode optical fiber and common G652D single-mode optical fiber, but also produce dispersion displacement single-mode optical fiber and dispersion compensation optical fiber with complex structure.

The deposition process of PCVD is to place the reaction tube in a constant heat-insulating furnace and introduce SiCl into the reaction tube₄,GeCl₄And the reaction gas forms active ions under the action of microwave plasma, and the active ions contact the inner wall of the reaction tube and are deposited on the inner wall of the reaction tube. The microwave moves back and forth along the reaction tube in a reciprocating translation way, and a micron-sized glass thin layer is deposited in each movement. The set refractive index profile can be obtained by adjusting the reactant proportion and concentration of the microwave during each reciprocating motion. The method has very high precision in the control of the refractive index profile, can obtain the refractive index profile of any shape which is wanted by people, and is the optimal choice for preparing the optical fiber with the complex refractive index profile. Although this method is very accurate in the control of the refractive index profile, the deposition of the reactants is affected in other ways. For example, non-uniform reactant concentrations at each deposition point, can affect the non-uniformity of the optical rod in the axial direction.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide optical fiber preform manufacturing equipment which can solve the problem that the reaction concentration of reactants in a reaction tube at each deposition point is inconsistent, so that an optical rod is not uniform in the axial direction in the prior art.

In order to achieve the above purposes, the technical scheme adopted by the invention is as follows:

the present invention provides an optical fiber preform manufacturing apparatus, comprising:

the sealing mechanism comprises a gas inlet end sealing element and a gas outlet end sealing element which are arranged at intervals and used for respectively sealing two ends of the reaction tube;

the resonant cavity is sleeved on the outer side of the reaction tube and can reciprocate along the axial direction of the reaction tube;

an inlet tube including an outlet end for extending into the reaction tube, the inlet tube passing through an inlet end seal, and the outlet end configured to reciprocate within the reaction tube in synchronization with the resonant cavity.

In some optional embodiments, the air inlet pipe further comprises a telescopic mechanism sleeved on the air inlet pipe, one end of the telescopic mechanism is connected with the air inlet end sealing element in a sealing mode, the other end of the telescopic mechanism is connected with the air outlet end in a sealing mode, and the telescopic mechanism can synchronously stretch along with the reciprocating motion of the air inlet pipe. The telescopic mechanism can enter the reaction tube or can not enter the reaction tube.

In some optional embodiments, the retractable mechanism comprises:

the isolating pipe is sleeved on the air inlet pipe, one end of the isolating pipe is connected with the air outlet end in a sealing mode, and the isolating pipe reciprocates along with the air outlet end;

and the telescopic unit is sleeved on the air inlet pipe, two ends of the telescopic unit are respectively connected with the isolation pipe and the air inlet end sealing element, and the telescopic unit can synchronously stretch along with the reciprocating motion of the isolation pipe.

In some optional embodiments, the outlet of the air inlet pipe is provided with a metal microwave isolation net.

In some optional embodiments, the reactor further comprises a holding furnace, which is used for being sleeved outside the reaction tube and the resonant cavity and providing a stable temperature field for reactants.

In some optional embodiments, the holding furnace comprises a front section, a middle section and a rear section which are temperature-controllable sections.

In some optional embodiments, temperature sensors are arranged in the three temperature-controllable sections in front of, in the rear of, the holding furnace.

In some optional embodiments, the reaction tube further comprises a negative pressure pumping device for connecting with the gas outlet of the reaction tube to maintain a constant pressure in the reaction tube.

In some optional embodiments, the apparatus further comprises a moving stage, connected to the resonant cavity, for driving the resonant cavity to reciprocate.

In some optional embodiments, the air conditioner further comprises a driving motor connected with the air inlet pipe and used for driving the air inlet pipe to reciprocate.

Compared with the prior art, the invention has the advantages that: the gas inlet pipe is communicated into the reaction pipe, the gas outlet end is close to the resonant cavity, the gas inlet pipe and the resonant cavity keep synchronous motion, the relative positions of the gas inlet pipe and the resonant cavity are kept consistent, and the consistency of the concentration of the reaction gas in the resonant cavity is ensured. By the mode, the concentration of reactants at the axial position of the optical rod is kept consistent when the microwave reciprocates back and forth in the deposition process of the optical rod. Therefore, the deposition consistency of each point in the axial direction of the optical rod is ensured, and the axial uniformity of the optical rod is improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic structural view of an apparatus for manufacturing an optical fiber preform according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a retractable mechanism according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a metal microwave isolation net according to an embodiment of the present invention;

in the figure: 11. an inlet end seal; 12. an air outlet end sealing member; 2. a reaction tube; 3. a resonant cavity; 4. an air inlet pipe; 41. a metal microwave isolation net; 5. a retractable mechanism; 51. a telescopic unit; 52. an isolation pipe; 6. a holding furnace; 7. the carrier is moved.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. Fig. 1 is a schematic structural view of an optical fiber preform manufacturing apparatus according to an embodiment of the present invention, as shown in fig. 1:

the present invention provides an optical fiber preform manufacturing apparatus, comprising: the sealing mechanism comprises a gas inlet end sealing piece 11 and a gas outlet end sealing piece 12 which are arranged at intervals and are used for respectively sealing two ends of the reaction tube 2; the device also comprises a resonant cavity 3 which is sleeved outside the reaction tube 2 and can reciprocate along the axial direction of the reaction tube 2; and a gas inlet pipe 4 including a gas outlet end for extending into the reaction tube 2, the gas inlet pipe 4 passing through the gas inlet end sealing member 11, and the gas outlet end being configured to reciprocate within the reaction tube 2 in synchronization with the resonant cavity 3.

In using the optical fiber preform manufacturing apparatus, the reaction tube 2 is mounted on the inlet end sealing member 11 and the outlet end sealing member 12, and the outlet end of the inlet tube 4 is extended into the reaction tube 2. And introducing reaction gas into the gas inlet pipe 4, opening the resonant cavity 3 to enable the resonant cavity to move in the axial direction of the reaction tube 2, and simultaneously driving the gas inlet pipe 4 to move in the reaction tube 2 to enable the translation speed of the gas inlet pipe 4 to be consistent with that of the resonant cavity 3. The reactants enter the reaction tube through the gas inlet tube 4 and are released inside the reaction tube 2 at the resonance chamber 3. The microwave resonant cavity is sleeved outside the reaction tube 2 and moves transversely along the reaction tube in a reciprocating manner, reactants are plasmatized under the action of microwaves and are deposited on the inner surface of the reaction tube with lower temperature. The device can make the air inlet pipe 4 and the microwave resonant cavity keep synchronous motion, so that the relative positions of the air outlet end of the air inlet pipe and the microwave resonant cavity are kept consistent, and the consistency of the concentration of reaction gas in the microwave resonant cavity is ensured. By the mode, the concentration of reactants at the axial position of the optical rod is kept consistent when the microwave reciprocates back and forth in the deposition process of the optical rod. Therefore, the deposition consistency of each point in the axial direction of the optical rod is ensured, and the axial uniformity of the optical rod is improved.

In this example, the reactant gas was heated to 60 ℃ in a gas cabinet and was delivered at a flow rate through a gas flow meter along a pipeline to a gas inlet pipeline. The resonant cavity 3 is a microwave resonant cavity, and reactants are ionized and deposited on the inner surface of the reaction tube 2 under the action of microwaves. The inlet gas supply device delivers the reactants into the reaction tube at a concentration and rate. The reaction gas is SiCl₄，GeCl₄，C₂F₆And other dopant gases. SiCl as the main reactant gas₄The flow rate of (1) is 780sccm, GeCl₄And other dopant gases may be set at different flow rates depending on the recipe. The gas inlet end sealing element 11 and the gas outlet end sealing element 12 are both magnetic fluids, and the magnetic fluids are connected with the reaction tube 4 and fixed through locking nuts.

Fig. 2 is a schematic structural diagram of a telescopic mechanism in an embodiment of the present invention, as shown in fig. 2, in some optional embodiments, the optical fiber preform manufacturing apparatus further includes a telescopic mechanism 5 sleeved on the gas inlet pipe 4, one end of the telescopic mechanism is hermetically connected to the gas inlet end sealing member 11, and the other end of the telescopic mechanism is hermetically connected to the gas outlet end, the telescopic mechanism 5 can synchronously extend and retract along with the reciprocating motion of the gas inlet pipe 4, and the telescopic mechanism can enter the reaction pipe and cannot enter the reaction pipe, and conditionally extend into the reaction pipe 2 and retract into the gas inlet end sealing member 11.

In this embodiment, the retractable mechanism 5 is connected to the air outlet end in a sealing manner and can perform a retractable movement, so that the air inlet pipe 4 can perform a reciprocating movement under a sealing condition, and the air outlet end of the air inlet pipe 4 and the microwave resonant cavity can keep a synchronous movement.

In some optional embodiments, the retractable mechanism 5 comprises: an isolation pipe 52, which is sleeved on the air inlet pipe 4, has one end hermetically connected with the air outlet end, and reciprocates together with the air outlet end; the air intake pipe sealing device further comprises a telescopic unit 51, wherein the telescopic unit 51 is sleeved on the air intake pipe 4, two ends of the telescopic unit are respectively connected with the isolation pipe 52 and the air intake end sealing element 11, and the telescopic unit 51 can extend and contract along with the reciprocating motion of the isolation pipe 52.

In this embodiment, the flexible unit 51 has flexibility, high airtightness, and a good physical shape after being contracted, thereby preventing the inner wall of the reaction tube 2 from being scratched. Both ends of the telescopic unit 51 are connected to the separation tube 52 and the inlet end sealing member 11, respectively. The isolation tube 52 is hermetically connected to the outer wall of the gas inlet end, so that the gas tightness in the reaction tube 2 is ensured and the gas inlet tube 4 can reciprocate in a sealed condition.

Fig. 3 is a schematic structural diagram of a metal microwave isolation net in an embodiment of the present invention, and as shown in fig. 3, in some optional embodiments, an outlet of the air inlet pipe 2 is provided with a metal microwave isolation net 41. In the embodiment, the outlet of the air outlet end is provided with the metal microwave isolation net, and the mesh size of the isolation net is 1-3 mm, so that microwaves can be effectively shielded. The negative effect of microwaves on unreacted gas in the metal pipeline is avoided.

In this example, the outer diameter D of the reaction tube 7 is 30 to 50 mm. The size of intake pipe 4 is 1 ~ 10mm, according to removable not unidimensional intake pipe 4 of reaction pipe 2 size. And simultaneously, the corresponding metal microwave isolation net 41 is replaced.

Referring again to fig. 1, in some optional embodiments, a holding furnace 6 is further included, which is configured to be sleeved outside the reaction tube 2 and the resonant cavity 3, and is configured to provide a stable temperature field for the reactants.

In this embodiment, the holding furnace 6 provides a certain heat source and a stable temperature environment for the deposition of the reaction tube, so that the reactants are better deposited on the inner wall of the reaction tube 2.

In some alternative embodiments, the holding furnace 6 comprises three sections of front, middle and rear controllable temperature sections.

In this embodiment, the holding furnace 6 sets the temperatures of the front, middle and rear portions, respectively, and the temperatures of the respective regions are maintained within the range of the set values by the combined compensation of the main carbon rod and the auxiliary carbon rod. Through the holding furnace, a stable temperature field is provided for the deposition of reactants. In this example, the temperature range set at the front, middle and rear ends of the holding furnace 6 is 950 to 1150 ℃.

In some optional embodiments, temperature sensors are arranged in the front, middle and rear three temperature-controllable sections of the holding furnace 6. In this embodiment, the front, middle and rear sections inside the holding furnace 6 are provided with temperature sensors, which can accurately detect the temperature of each position, thereby better controlling the temperature of the front, middle and rear sections of the holding furnace 6.

In some optional embodiments, the optical fiber preform fabricating apparatus further comprises a negative pressure pumping device for connecting to the gas outlet of the reaction tube 2 to maintain a constant pressure inside the reaction tube 2.

In this embodiment, the reactant gas is mainly SiCl₄，GeCl₄，C₂F₆And other doping gases, since the main reaction gas is SiCl₄There are also some unreacted gases that need to be pumped out to maintain the pressure inside the reaction tube 2. Just because some gas need be taken out, if the intake pipe 4 is always located at one end, the concentration of the reaction gas at the outlet end of the intake pipe 4 in the reaction tube 2 is high, and the concentration of the reaction gas at the outlet of the reaction tube 2 is low, which results in uneven deposition in the reaction tube 2. In this case, the negative pressure pumping device can ensure that the flow and concentration of reactants are not disturbed by pressure in the deposition process, and the concentration of the reaction gas at each reaction point is consistent by the reciprocating gas outlet end, so that the deposition of each point is uniform.

In some optional embodiments, the optical fiber preform manufacturing apparatus further includes a movable stage 7 connected to the resonant cavity 3 for driving the resonant cavity 3 to reciprocate. In this embodiment, the driving cavity 3 is reciprocated by moving the stage 7, so that the gas in the reaction tube 2 is slowly deposited layer by layer.

In some optional embodiments, the optical fiber preform manufacturing apparatus further includes a driving motor connected to the air inlet tube 4 for driving the air inlet tube 4 to reciprocate. In this embodiment, the speed and the stroke of the driving motor for driving the air inlet pipe 4 to reciprocate are adjustable to adapt to the reciprocating speed of the resonant cavity 3, so that the air inlet pipe 4 and the resonant cavity 3 run synchronously. In this example, the air inlet pipe 4 is driven by the driving motor, the air outlet end and the microwave resonant cavity move back and forth along the pipeline, and the moving speed is 30 m/min.

In addition, the scheme provides a specific embodiment, and the power of the microwave generator is adjustable between 3kw and 15 kw. The vapor pressure in the reaction tube is 5-15 torr. The reaction tube 2 had a size of 50 × 2.5 × 1600. The temperatures of the three sections of the heat preservation furnace 6, namely the inlet section and the outlet section are 1040 ℃,980 ℃ and 1021 ℃ respectively, so that a stable temperature environment is provided for deposition. The microwave power was 6.5 kw. The moving speed of the moving carrier is 30 m/min. The reactant flow rates were SiCl4, 670sccm, GeCl4, 104sccm, and C2F6, 10sccm, respectively. The total number of passes through the deposition was 5000 passes.

And adjusting the speed of the driving motor of the air inlet pipe 4 to ensure that the translation speed of the air inlet pipe 4 is consistent with that of the microwave resonant cavity. The reactants enter the reaction tube through the gas inlet pipe and are released into the reaction tube at the microwave resonant cavity. The reaction product is ionized and deposited on the inner surface of the reaction tube by the action of the microwave. The translation speed of the air inlet pipeline and the microwave resonant cavity is 30 m/min. By this embodiment the axial homogeneity of the preform is greatly improved, especially at the location of the gas inlet end and the gas outlet end. The effective length of the core rod is 1000mm, wherein the outer diameter dimension is maintained within a deviation range of +/-0.2 mm within the effective core rod length of 25-975 mm. The refractive index profiles are completely coincident. The process method provided by the invention has originality and feasibility, and can effectively enhance the axial uniformity problem of the PCVD prepared optical fiber preform.

In the description of the present application, it should be noted that the terms "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are only for convenience in describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present application. Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

It is noted that, in the present application, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The above description is merely exemplary of the present application and is presented to enable those skilled in the art to understand and practice the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.