KR100209362B1 - Method and apparatus for making optical fiber - Google Patents

Abstract

The present invention relates to a method and apparatus for manufacturing an optically amplified optical fiber to which rare earth elements are added, and more particularly, to a method and an apparatus for effectively adding erbium (Er) and aluminum (Al) to an optical fiber core. In the example of the optical amplification optical fiber manufacturing process using Al as an additive and erbium as a rare earth element, high-purity Al is added using AlCl ₃ in powder form using a bubbler to cause loss due to light scattering. Metallic aluminum that is prevented from remaining in the optical fiber core of unreacted Cl ₂ and can be reused several times to several times by filling the bubbler with AlCl ₃ powder once, and is performed every process when using conventional metal aluminum as a source. It is easy to process because there is no need for replacement, and it can be used for manufacturing optical amplified optical fiber because it can install many additives bubblers. Is that it is possible to add a variety of additives at the same time, it is stable in air than ErCl ₃ to Er source handle convenient ErCl ₃ 6H was used ₂ O, it is fine particles by the use of ethanol when added to the ampule tube from entering the reaction tubes It can be suppressed to reduce the generation of bubbles during the sealing process, such as advantageous in the manufacturing process can improve the process yield and the reliability of the device operation.

Description

Method for manufacturing optically amplified optical fiber added with rare earth elements and apparatus for manufacturing same

The present invention relates to a method for manufacturing an optical amplified optical fiber to which rare earth elements are added, and a device for manufacturing the same. Especially, the rare earth elements and the additives can be effectively added to the optical fiber core to simplify the process, improve the yield, and have excellent reproducibility. The present invention relates to a method for manufacturing an optically amplified optical fiber to which a rare earth element is added, and an apparatus for manufacturing the same.

In general, optical fibers used in optical communication are classified into various types according to the composition, transmission mode, refractive index distribution, and manufacturing method of the glass material constituting the optical fiber. The optical fiber is mainly used. The lower cladding consists of a primary coating for protecting them, a buffer and a secondary coating.

As shown in FIG. 1, a conventional optical fiber is formed so as to surround the optical fiber core 41, which is a portion having a higher refractive index and a light passing portion, as a central portion, and a portion through which the light passes. It is composed of an optical fiber clad (42) that serves to trap the light by the refractive index difference, the refractive index is lower than the core 41, the erbium (Er) and aluminum ( An Er / Al addition region 43 to which Al) is added is formed.

Such an optical fiber has a refractive index distribution as shown in FIG. 2 and confines light to the core by the difference in refractive index.

As a method of adding a rare earth element to the optical fiber core, there are largely a liquid phase method and a vapor phase doping method.

First, the liquid phase method is a method of preparing an optical fiber preform by dissolving a rare earth element and an additive such as Al in a solvent such as water or ethanol and depositing it on a porous optical fiber core, followed by vitrification at high temperature. This method has the advantage that it can manufacture rare earth element-added fiber (Erbium Doped Fiber) without greatly changing the existing single mode fiber manufacturing method, but MCVD the reaction tube during the manufacturing process for erbium doping It must be removed from the machine's lathe, immersed in the rare earth-added solution and then mounted on the shelf again. In this case, impurities may be contaminated, and the removal of the reaction tube takes much more time than other manufacturing methods, and process conditions such as concentration or time when immersing in a rare earth-added solution, or flow rate or deposition of reactants. It is difficult to control the porous core deposition conditions, such as temperature, there is a disadvantage that is less reproducible.

Another method, the vapor phase method, is a method of vaporizing rare earth elements and additives during the core manufacturing process of an optical fiber base material and adding them together with reaction chemicals such as SiCl ₄ or GeCl _4, and the gas phase method is the amount of carrier gas. It is easy to control the addition amount of rare earth elements and sub-additives by precisely controlling the amount, and there is no solution doping process, so it is possible to prevent the intrusion of impurities such as water and to shorten the process time. The gas phase method has several major drawbacks because it uses ErCl ₃ powder as the source of erbium and metal Al as the source of Al.

That is, as shown in the following equation, the metal Al is reacted with chlorine gas to synthesize aluminum chloride (AlCl ₃ ), and then AlCl ₃ vapor is supplied into the reaction tube using a transfer gas such as He.

2AlCl₃(g)2Al (s) + 3Cl ₂ (g)

2AlCl ₃ (g)

In this case, impurities that are not reacted with metallic aluminum particles or chlorine are likely to remain in the optical fiber core, causing light scattering loss.

In addition, the conventional gas phase method is to react the metal aluminum with chlorine gas to form AlCl ₃ vapor and then supply it to the rotary joint, where the reaction of reacting with the amount of metal aluminum and chlorine to generate an appropriate amount of AlCl ₃ steam Since the area must be constant, and the amount of transport gas, the amount of chlorine gas, and the reaction temperature must be precisely controlled, there are many problems in the manufacturing process, which are very demanding and have low reproducibility.

In addition, in the conventional gas phase method, the metal aluminum has a complicated purification process, making it difficult to manufacture high-purity aluminum, and there is another problem of increasing the manufacturing cost at a high cost.

In addition, in the conventional gas phase method, when ErCl ₃ is attached to the ampoule tube, powder type ErCl ₃ is directly added. When a sudden pressure change occurs in the reaction tube, ErCl ₃ or Al particles in the ampoule tube enter the reaction tube. In addition, these fine particles generate another bubble during the sealing process, or cause optical loss during optical fiber manufacturing, thereby decreasing optical communication efficiency.

The present invention is to solve the above problems, an object of the present invention by supplying AlCl ₃ vapor directly to the rotary joint using AlCl ₃ powder by appropriately adjusting the amount of the transfer gas and the temperature of the bubbler desired desired vapor pressure Because of the simple manufacturing process and small process variables, the reproducibility is excellent, and the amount of addition of aluminum as an auxiliary additive can be easily controlled, and the rare earth element that can reduce the manufacturing cost by not using expensive high-purity metal Al The present invention provides a method for manufacturing an added optically amplified optical fiber.

In addition, another object of the present invention is to dissolve ErCl ₃ in ethanol and inject the erbium mixed solution into the tube to uniformly and firmly applied to the inner wall of the tube to prevent unreacted ErCl ₃ particles from entering the core. The present invention provides a method for manufacturing an optical fiber which can prevent the decrease in optical communication efficiency due to the mixing of chlorine gas without using a reaction gas.

It is still another object of the present invention to provide a manufacturing apparatus capable of producing an optical fiber core of excellent material by effectively vaporizing and adding subadditives and other rare earth elements having different vapor pressures.

1 is a cross-sectional view of a conventional optical fiber.

2 is a refractive index distribution diagram of the optical fiber of FIG.

3 is a schematic diagram of an optical amplification optical fiber manufacturing apparatus according to the present invention.

4 is a cross-sectional view of the Al supply apparatus of the optical fiber manufacturing apparatus of FIG.

5 is a cross-sectional view of the erbium doping apparatus of FIG.

* Explanation of symbols for main parts of the drawings

11: aluminum feeder 12: erbium doping apparatus

13 main burner 14 light thermometer

15: reaction tube 21: electric oven

22: bubbler 23: heating element

24: transfer gas line 25: additive gas line

26: hot wire 27: aluminum compound

28: temperature sensor 29: quartz tube

31: rotary joint 32: ampoule tube

33: Erbium compound 34: Rotary joint heating wire

35: heater tube 36: ribbon burner

37 Reaction Chemical Line 41 Fiber Optic Core

42: fiber cladding 43: Er / Al addition area

A feature of the optical amplified optical fiber manufacturing method according to the present invention for achieving the above object is, of the optical amplified optical fiber to which the rare earth element comprising at least one or more additives, the erbium doping apparatus, the ampoule tube and the reaction tube is added A method of manufacturing an optical fiber by a vapor phase method using a manufacturing apparatus, comprising: mounting a powder-like subadditive compound on the subaddition supply device; applying and drying a liquid rare earth compound on one side of the ampoule tube; and the ampoule. Mounting the tube and the reaction tube installed on the outside of the rotary joint of the MCVD shelf, and the main burner moved from side to side from the bottom of the reaction tube to the left and right, and supplying impurity gas, Depositing an inner clad layer, vapor evaporating the subadditive compound, and Supplying steam evaporated the rare earth compound of the ampoule tube to form a core layer containing additives, drying and sintering the core layer, a collabs process to reduce the empty space inside the reaction tube, And a sealing process for removing space of the collapsed tube and a polishing process for heating the sealed preform.

According to another aspect of the present invention, in the optical amplification optical fiber manufacturing apparatus to which the rare earth element is added, a rotary joint having a reaction gas line fixed to one side and a reaction tube rotating to the other side is connected, and the rotary joint It is connected to one side, provided with at least one or more additives for supplying the powder-like additive compound inside the ampoule tube by heating the vapor, mounted on the inside of the reaction tube, a rare earth compound is applied to one side An ampoule tube, a ribbon burner for evaporating the rare earth compound, and a main burner for heating the reaction tube and moving left and right.

Hereinafter, a method for manufacturing an optically amplified optical fiber to which a rare earth element is added according to the present invention and a manufacturing apparatus thereof will be described in detail with reference to the accompanying drawings.

3 to 5 are diagrams for explaining an apparatus for manufacturing an optically amplified optical fiber to which a rare earth element is added according to the present invention.

First, in the optical amplification optical fiber manufacturing apparatus to which the rare earth element is added according to the present invention, as shown in FIG. 3, an AlCl ₃ mixed vapor vaporizing an aluminum compound is supplied into the ampoule tube of the erbium doping apparatus 12. An aluminum delivery system 11 and an erbium doping system 12 which vaporize the erbium compound and mix it with AlCl ₃ vapor and then supply it to the reaction tube 15, SiCl ₄ , which is a reaction chemical, The reaction tube (Substrate Tube; 15), which is a silica glass tube on which GeCl ₄ , POCl _3, etc., additives such as Er and Al are deposited, moves to the left and right, and the reaction tube 15 is heated to SiCl ₄ , GeCl _4, POCl A main burner 13 for depositing reaction chemicals such as ₃ and additives such as Er and Al into the reaction tube 15, and a ribbon burner 36 provided in the erbium supply device 12, and To measure the tube heating temperature of the main burner (13) Pyrometer 14 can be divided into its configuration.

The aluminum supply device 11 is an oven for maintaining the temperature of the bubbler 22 at a constant temperature, and an electric oven 21 for raising above the evaporation temperature of AlCl ₃ and the electric oven 21. And a quartz tube filled with a heating element 23 which is a heating wire for raising the temperature and a powder-shaped aluminum compound 27 which is placed in the electric oven 21 and becomes a raw material of aluminum as an additive. A carrier gas line (29) having a bubbler (bubbler) 22 for vaporizing the negative additives and a helium, which is a transfer gas, is supplied to one side of the bubbler 22 into the bubbler 22. 24) and an auxiliary additive gas line (AlCl) insulated and insulated so that vaporized AlCl ₃ vapor is not re-deposited as a line for supplying the AlCl ₃ vapor vaporized in the bubbler 22 to the rotary joint 31; ₃ gas line 25 and the vaporized AlCl ₃ vapor It is provided with a heating line (26) for heating so as not to be deposited again to cool, and a temperature sensor (Senser Rod) 28 for measuring the internal temperature of the bubbler (22).

In addition, the erbium doping apparatus 12 vaporizes the erbium compound 33 with the ribbon burner 36 and mixes it with AlCl ₃ vapor, and then supplies the reaction tube 15 to the fixed chemical line 25. , 37) and a rotary joint 31, which is designed so that chemicals do not leak as a device for connecting the rotating reaction tube 15 to the rotary joint 31, and mounted in the reaction tube 15. _{located, ErCl 3 6H 2 O (33} ) is uniformly applied to the tube inner wall and delivered evenly to heat by the ribbon burner 36, the AlCl ₃ mixed vapor passing through the AlCl ₃ gas line 25 passes through the part The end of the ampoule tube 32 is formed to be thin and long so as to collect and pass the ErCl ₃ (33) vaporized by the ribbon burner 36, and the inside of the ampoule tube (32) Addition of erbium (Er), an additive, in ethanol Air erbium compound 33, the AlCl ₃ gas line (25) AlCl ₃ gas mixture is rotary joint has passed through the 31 and the ampoule tube 32 as an apparatus to heat from being cooled while passing through the heater tubes A rotary joint heating wire 34 installed inside the 35, a heater tube 35 to prevent the rotary joint heating wire 34 and the AlCl ₃ mixed vapor from reacting with each other, and the ampoule tube A ribbon burner (36) which heats the ErCl ₃ (33) evenly coated in the 32 and the position and the angle so that the ErCl ₃ is applied to the end portion of the ampoule tube (32). A process chemical line 37 is connected to the rotary joint 31 to supply reaction chemicals SiCl ₄ , GeCl _4, POCl ₃ , and the like into the reaction tube 15.

튜브장착(tube setup)

튜브 폴리싱(tube polishing)

내부 클래드층 증착(Inner Clade Deposition)

코어층 증착(Core Deposition)

건조 및 신터링(Dehydration and Sintering)

컬랩스 및 실링(Collapse Sealing)

모재 폴리싱(Preform Polishin g)

광섬유 모재 인출의 공정을 거치게 되는데, 이를 상세히 살펴보면 다음과 같다.Optical amplification optical fiber manufacturing using the optical fiber manufacturing apparatus configured as described above, as shown in the flow chart below, the preparation step (dopants)

Tube setup

Tube polishing

Inner Clade Deposition

Core Deposition

Dehydration and Sintering

Collapsing and Collapse Sealing

Preform Polishin g

It goes through the process of drawing the optical fiber base material, which is described in detail as follows.

First, as a step of preparing the additive, prior to the optical fiber preform manufacturing process, the bubbler 22 mounted in the electric oven 21 of the aluminum feeder 11 is detached to remove the powdery AlCl ₃ aluminum compound 27. The quartz tube 29 of the bubbler 22 is filled. At this time, the AlCl ₃ reacts very strongly with moisture, there is a risk of explosion, and the AlCl ₃ vapor is very toxic to the human body, so care must be taken when filling. In consideration of these characteristics, AlCl ₃ filling is performed in a glove box in a dry nitrogen atmosphere, and the bubbler 22 is filled with AlCl ₃ about 1/3 and locked with a mechanical valve to prevent leakage. , The bubbler 22 is mounted in the electric oven 21 again.

Erbium (Er) is then prepared, and the source of erbium is ErCl ₃ 6H ₂ O powder (Powder), the powdered erbium compound (ErCl ₃ 6H ₂ O; 33) directly into the ampoule tube (32) Particles may enter the reaction tube 15 due to a sudden pressure change and contaminate the tube. Therefore, special attention is required in processes where pressure changes occur such as reaction tube mounting processes, tube polishing processes, and internal clad deposition processes. need. Therefore, in the present invention, as a wet method, ErCl ₃ 6H ₂ O powder is completely dissolved in ethanol, an appropriate amount is injected into one side of the ampoule tube 32 using a syringe, and the ampoule tube ( Slowly rotate 32) and dry appropriately with nitrogen gas.

Then, the ampoule tube 32 containing the erbium compound 33 is mounted on the rotary joint 31 of the MCVD lathe, and the reaction tube 15 is washed and installed on a lathe. 31). At this time, the ampoule tube 32 is located inside the reaction tube 15, and the ampoule tube 32 is slowly heated by the ribbon burner 36 and erbium in the ampoule tube 32 is firmly attached to the inner wall of the tube.

Next, the rotary joint heating wire 34 and the heater tube 35 are mounted on the rotary joint 31, and then the position of the ribbon burner 36 is adjusted to be positioned on the erbium-coated portion of the ampoule tube 32. .

Thereafter, fine defects or foreign matters may remain inside or outside the reaction tube 15, and in particular, a small amount of particles may flow into the tube during ErCl ₃ 6H ₂ O mounting, thereby performing a tube polishing process. First, the tube 15 is heated to a high temperature of about 1900 ° C., and the inside of the tube is etched using a C ₂ F ₆ mixed gas, for example, helium 1500sccm, oxygen 500sccm, and C ₂ F ₆ 20sccm.

Then, the internal clad deposition is performed prior to core deposition of the optical fiber. After fixing the temperature of the bubbler (not shown) containing the halogenated SiCl ₄ , _and POCl ₃ to 25 ± 1 ° C., the transfer gas of oxygen ( The amount of reactants was controlled by MFC using O ₂ ), but SiCl ₄ 500sccm, POCl ₃ 90sccm, O ₂ 500sccm and C ₂ F ₆ 10sccm were added to reciprocate the main burner 13 at least 15 times to obtain a desired thickness. Forming, the deposition temperature was increased by 2 ℃ in each pass (pass) on the basis of 1840 ℃ to correct the temperature drop due to the deposition. Temperature measurement was performed using a pyrometer that detects the electromagnetic wave intensity in the wavelength range of 4.8㎛.

Since other reactants exist in the high pressure gas state, they are supplied directly to the reaction zone, and the oxygen gas used as the transfer gas and the reactant gas contains several ppm of moisture and impurities, even at high purity. It is passed through the purifier and the moisture remover to the reaction zone. At this time, the deposition process of the inner clad prevents impurities such as OH ^- ions contained in the reaction tube 15 from penetrating into the core, and since a part of the light propagating in the core passes through the cladding layer, the clad has a high purity. It is to reduce the loss caused by impurities by depositing a layer.

Then, in order to be a core layer deposition process Er and Al elements in the gas phase method are appropriately added to the core layer it be such that first vaporize to this element to heat the AlCl ₃ bubbler 22 is at least about 200 ℃ AlCl ₃ (27 ) Have an appropriate vapor pressure, but before the core deposition, the AlCl ₃ supply line 25 and the heater tube 35 should be heated to 200 ° C or higher, and the ErCl ₃ (33) of the ampoule tube 32 has an internal cladding. After the layer is deposited, it is heated with a ribbon burner 36 to have an appropriate vapor pressure. By precisely controlling the amount of helium, which is a transport gas, Er and Al elements are added to the core layer 41 together with the reactants (SiCl ₄ , GeCl _4, etc.) at the same time. At this time, the amount of transport gas depends on the design of the optical amplification fiber, and the core deposition temperature is set so that the reactants are not completely sintered. This is because ErCl ₃ and AlCl ₃ have a very good affinity for moisture, This is because there is a possibility that some degree of moisture is contained inside the tube.

Then, after the core deposition process is completed, as a drying and sintering process, first heating gradually while reciprocating to the main burner 13 in order to completely remove the small amount of water remaining in the core 41, He and Cl ₂ After the gas is flowed into the reaction tube 15 to completely remove moisture remaining in the core layer, Ge is not burned off in the sintering process of completely vibrating the porous core layer. Do not operate within the temperature range. Here, the heating to the end of the ampoule tube 32 ErCl ₃ steam and AlCl ₃ is the end use of small and long tube the mixed vapor to be uniformly mixed and applied and, by using the ribbon burner 36 ampoule tube 32 .

Then, when the deposition process is completed, the process of collapsing to reduce the empty space inside the reaction tube 15 is carried out. The collapsing process heats the reaction tube at a high temperature above the softening point of the glass and maintains the shape of the surface of the quartz glass. After being slowly squeezed by tension, the sealing process completely eliminates the space of the collapsed tubes at appropriate intervals and moves the main burner 13 at a slower speed at the collapsing temperature to completely eliminate the internal space. Make preforms in the form of rods.

Then, the polishing process is performed by heating the base material surface to a temperature lower than the Collabs temperature in order to remove the uneven portion and the opaque oxide, etc., on the surface of the base material after the sealing is completed at a high temperature. Proceed.

In the above, only one Al additive is provided as an example, but the same effect can be obtained by installing a plurality of additive feeders, which is also the case in the rare earth feeder.

As described above, the manufacturing method and apparatus for manufacturing an optical amplified optical fiber to which the rare earth element is added according to the present invention are powdered AlCl ₃ using a bubbler as a method for adding Al in the optical fiber manufacturing process by vapor phase method. By using it, it is possible to prevent the remaining of unreacted Cl ₂ and unreacted metal aluminum in the optical fiber core, which causes loss due to light scattering, and to re-use the AlCl ₃ powder in the bubbler once for several to several ten times. In the case of using metal aluminum as a source, it is not necessary to replace the metal aluminum performed at every process, and the process is easy, and a large number of additive-added bubblers can be installed to add various additives used in manufacturing optical amplification optical fibers. can, to deal with stability in air than ErCl ₃ to Er source used for convenient ErCl ₃ 6H ₂ O Was, the normal manufacturing process advantages such as favorable to suppress them from entering the fine particles to the reaction tube by the use of ethanol was added to the ampoule tube can reduce the occurrence of bubbles during the sealing process.

Claims (18)

A method of manufacturing an optical fiber by a vapor phase method using at least one additive-adding device, an erbium doping apparatus, and an apparatus for producing an optical amplified optical fiber with a rare earth element including an ampoule tube and a reaction tube, wherein the additive-adding device has a powder shape Mounting a secondary additive compound of the present invention, applying and drying a liquid rare earth compound on one side of the ampoule tube, and attaching the ampoule tube and a reaction tube installed outside thereof to a rotary joint of an MCVD lathe; A process of depositing an inner clad layer of an optical fiber containing an additive while supplying an impurity gas while supplying an impurity gas from a lower part of the reaction tube to the left and right, vapor and evaporating the additive compound, and the ampoule Supply the vapor evaporating the rare earth compound in the tube and Forming process, drying and sintering the core layer, collapsing process for reducing the empty space inside the reaction tube, sealing process for eliminating the space of the wrapped tube, and heating the sealed preform The manufacturing method of the optically-amplified optical fiber which the rare earth element added to the polishing process to add. The method of manufacturing an optical amplified optical fiber with a rare earth element according to claim 1, wherein the additive addition device is an Al supply device. [Claim _3] The optical amplification optical fiber of claim 2, wherein AlCl ₃ is used as a secondary additive compound of the Al feeder, and the feeder is filled in a feeder in a glove box in a dry nitrogen atmosphere. Manufacturing method. The method of claim 1, wherein the rare earth compound is one compound arbitrarily selected from the group consisting of Er, Yb, La, Nd, and Pr. The method of claim 1, wherein when using the rare earth compound as Er, ErCl ₃ 6H ₂ O powder is dissolved in ethanol and evenly applied to the inner wall of the ampoule tube, dried by using nitrogen gas while slowly rotating the ampoule tube A method for producing an optically amplified optical fiber to which a rare earth element is added. The method of claim 1, further comprising etching the reaction tube with a C ₂ F ₆ mixed gas while heating the reaction tube at 1900 ° C. after the reaction tube is mounted. The method of manufacturing an optical amplified optical fiber with a rare earth element according to claim 1, wherein the vapor of the halogen compound is formed while controlling the amount of reactants by MFC using an oxygen transport gas during deposition of the inner clad. The method of claim 7, wherein the internal clad deposition is formed while reciprocating the main burner by adding SiCl ₄ 500 sccm, POCl ₃ 90 sccm, O ₂ 500 sccm, and C ₂ F ₆ 10 sccm, and the deposition temperature is based on 1840 ° C. A method of manufacturing an optically amplified optical fiber with a rare earth element, characterized in that the temperature drop due to deposition is corrected by increasing the temperature by 2 ° C for each pass. The rare earth element of claim 1, wherein the process of drying the core layer is gradually heated while reciprocating the main burner, and the He and Cl ₂ gases are flowed into the reaction tube to remove moisture remaining in the core layer. Method for manufacturing added optically amplified optical fiber. The method of manufacturing an optically amplified optical fiber with a rare earth element according to claim 1, wherein the sintering step is performed within a temperature range in which Ge is not burned off. The optically amplified optical fiber with a rare earth element according to claim 1, wherein the collapsing process is performed by heating the reaction tube at a temperature higher than the softening point of the glass so as to be gradually depressed by the surface tension of the quartz glass while maintaining the circular shape. Method of preparation. The method of claim 1, wherein the sealing process comprises forming a glass rod by moving the main burner at a slower speed at a collapsing temperature to remove internal spaces. The method of manufacturing an optically amplified optical fiber with a rare earth element according to claim 1, wherein the polishing process is performed by heating the surface of the base material to a temperature lower than the collabs temperature. In the optical amplification optical fiber manufacturing apparatus to which the rare earth element is added, a rotary joint having a reaction gas line fixed to one side and a reaction tube rotating to the other side is connected to at least one of the rotary joints. And a subaddition supply device for heating the powdery subadditive compound and supplying it to the inside of the ampoule tube with steam, and an ampoule tube mounted inside the reaction tube and coated with a rare earth compound on one side thereof, and An apparatus for manufacturing an optical amplified optical fiber having a rare earth element added thereto comprising a ribbon burner for evaporating a rare earth compound and a main burner which is heated to the reaction tube and moves from side to side. The apparatus of claim 13, wherein the rare earth element is added to SiCl ₄ , GeCl ₄ , or POCl ₃ through the reaction gas line. The apparatus of claim 13, wherein the reaction tube is a silica glass tube. 15. The apparatus of claim 13, wherein the auxiliary additive supplying device comprises a heating oven having a heating element capable of raising the vaporization temperature of the auxiliary additive compound as a bubbler, and a vessel in which the auxiliary additive powder is contained and mounted in the vessel. A rare earth element-added optical amplification optical fiber manufacturing apparatus having a temperature sensor provided and a secondary additive supply line for supplying a vaporized secondary additive mixed vapor to a rotary joint. 15. The apparatus of claim 13, wherein a heating wire for preventing redeposition of vaporized gas is provided in a line for supplying the vaporized secondary additive gas in the secondary additive supply device.

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