A method for manufacturing an erbium rare earth ion and cerium rare earth ion co-doped optical fiber preform

Abstract

The application discloses a preparation method of an erbium-rare earth ion and cerium-rare earth ion co-doped optical fiber preform rod. A heat source outside a quartz reaction tube is used to make reaction gas react in the quartz reaction tube and deposit on the inner wall of the quartz reaction tube. Rare earth ion raw materials are a mixture of erbium and cerium rare earth chelates with a designed proportion, the mixed rare earth chelates are laid in a tray and put into a sealed tank. Before a preform rod deposition reaction is performed, the sealed tank is heated to above a sublimation temperature of the rare earth chelates and is kept warm. When the preform rod deposition reaction starts, hot helium is introduced into the sealed tank, and the hot helium carries the sublimated rare earth chelates into the quartz reaction tube when flowing. The application solves the problem that the proportion of two kinds of raw materials entering the reaction tube changes due to inconsistent heating and airflow difference of the raw materials in a traditional method, and realizes accurate control of the proportion of the two kinds of raw materials.

Description

Technical Field

[0001] This invention relates to optical fiber preform preparation technology, and in particular to a method for preparing an optical fiber preform co-doped with erbium rare earth ions and cerium rare earth ions. Background Technology

[0002] In recent years, rare-earth ion-doped fiber lasers have gained increasing attention due to their advantages such as high beam quality, small size, high speed, and long lifespan. They have been widely applied in numerous fields, including laser welding, medical applications, and laser communication. With the development of laser technology, the application areas of rare-earth-doped fibers are becoming increasingly broad, while the requirements for these fibers are also becoming more stringent. Meeting specific application requirements necessitates the co-doping of multiple rare-earth ions.

[0003] The core component of a fiber laser is rare-earth ion-doped fiber. The fabrication process of rare-earth ion-doped fiber involves incorporating rare-earth ions into an optical fiber preform using liquid-phase doping and vapor-phase doping methods, followed by drawing the preform into an optical fiber. In the vapor-phase doping method, vaporized rare-earth raw materials are fed into a reaction tube, where rare-earth ions react and deposit on the inner wall of a quartz tube. The quartz tube is then contracted into a rod, forming the rare-earth ion-doped fiber preform.

[0004] The usual method is to vaporize and transport the various rare earth ions to be co-doped separately. This co-doping method is easily affected by the vaporization temperature and the flow rate of the transport gas, which can lead to problems such as uneven doping and imbalance of co-doping ratio. Summary of the Invention

[0005] To address the issue of temperature sensitivity in rare earth ion vaporization in traditional methods, and the tendency for uneven concentrations of the two absorbed ions and imbalances in their doping ratios due to temperature fluctuations between two feed tanks or feed paths when co-doping with multiple rare earth ions, thus affecting the unstable absorption and luminescence performance of optical fibers, this invention provides a method for preparing erbium (Er) 3+ Rare earth ions, cerium (Ce) 3+ A method for preparing rare-earth ion co-doped optical fiber preforms. This method utilizes Er... 3+ Ce 3+ The rare earth ion mixture is pre-mixed according to the designed proportions of the raw material components. The mixture is then placed in a single tank for heating, and the raw materials are subsequently transported into the reaction tube through the same pipeline. This avoids Er... 3+ Ce 3+ This study addresses the problem of uneven doping of rare earth ion raw materials due to temperature differences in different tanks and pipelines, as well as the imbalance in the doping ratio of the two ions, aiming to improve the uniformity of doping of the two rare earth ions.

[0006] The technical solution adopted by the present invention to achieve the above objectives is as follows: A method for preparing erbium rare earth ion and cerium rare earth ion co-doped optical fiber preform uses a mixture of erbium and cerium rare earth chelates as raw materials, and the preparation steps are as follows:

[0007] Step 1: Mix a certain amount of erbium and cerium rare earth ion chelate in a ratio of 1:3 to 1:7.

[0008] Step 2: Spread the mixed erbium and cerium rare earth ion chelate evenly on the material tray and put it into the sealed material tank; the upper end of the sealed material tank is equipped with an air inlet and the lower end of the sealed material tank is equipped with an air outlet; the gas pipeline at the front end of the air inlet and the sealed material tank are equipped with heating devices.

[0009] Step 3: Heat the sealed material tank and the gas pipeline at the front end of the air inlet to 180℃-200℃ respectively.

[0010] Step 4: When the preform deposition reaction begins, helium gas is introduced into the sealed container. The helium gas passes through a gas pipeline with a heating zone of 80cm ± 10cm and enters the sealed container through the gas inlet at the top of the container. As the hot helium gas flows, it carries the sublimated erbium and cerium rare earth ion chelate mixture into the quartz reaction tube through a feed pipe equipped with a heating device.

[0011] Step 5: After the preform deposition reaction is completed, the preform is shrunken and collected to obtain an erbium rare earth ion and cerium rare earth ion co-doped optical fiber preform.

[0012] This method involves horizontally fixing a quartz reaction tube on a reaction lathe and continuously introducing rare earth ion raw materials and reactive gases such as SiCl4 into the quartz reaction tube. A heat source outside the quartz reaction tube causes the reactive gases to react and deposit on the inner wall of the tube. The rare earth ion raw material is a mixture of erbium and cerium rare earth ion chelates in a designed ratio. The mixed rare earth ion chelates are spread evenly in a tray and placed in a sealed container. Before the preform deposition reaction, the sealed container is heated above the sublimation temperature of the rare earth chelates and held at that temperature. When the preform deposition reaction begins, hot helium gas is introduced into the sealed container, allowing the flowing hot helium to carry the sublimated rare earth ion chelates into the quartz reaction tube.

[0013] The advantages of this invention are: This method uses a mixture of two rare earth ion chelate raw materials for vapor-phase doping. The two raw materials can be mixed according to the required ratio, and then the mixed raw materials are placed in the same sealed container, where the same sealed container and the inflowing gas are heated to the same temperature. The two raw materials in the mixture undergo the same heating temperature and gas flow rate, solving the problem of inconsistent heating of the raw materials and differences in gas flow that leads to variations in the ratio of the two raw materials entering the reaction tube in traditional methods, thus achieving precise control of the ratio of the two raw materials. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the material flow path for the rare earth ion chelate mixture in an embodiment of the present invention.

[0015] In the diagram: 1-material tray; 2-sealed material tank; 3-air inlet; 4-gas pipeline; 5-heating belt; 6-air outlet; 7-material conveying pipe; 8-quartz reaction tube. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] Reference Figure 1 This embodiment uses the fabrication process of a common erbium-cerium rare-earth ion co-doped optical fiber preform as an example, and the steps are as follows:

[0018] Step 1: Put a certain amount of erbium and cerium rare earth ion chelate into a dry beaker at a ratio of 1:3 to 1:7, and stir manually with a glass rod to mix them.

[0019] In this embodiment, 2 grams of erbium rare earth ion chelate and 8 grams of cerium rare earth ion chelate are mixed evenly in a ratio of 1:4.

[0020] Step 2: Spread the mixed erbium and cerium rare earth ion chelate evenly on the material tray 1 and put it into the sealed material tank 2; the upper end of the sealed material tank 2 is provided with an air inlet 3 and the lower end of the sealed material tank 2 is provided with an air outlet 6; the gas pipeline 4 at the front end of the air inlet 3, as well as the sealed material tank 2 and the conveying pipe 7 are all equipped with heating devices, and the tank wall of the sealed material tank 2, as well as the gas pipeline 4 and the conveying pipe 7 at the front end of the air inlet 3 are all wrapped with heating tape 5.

[0021] Step 3: Before the preform deposition reaction, the sealed tank 2 is not vented. The gas pipeline 4 at the front end of the sealed tank 2 and the air inlet 3 is heated to 180℃-200℃ respectively.

[0022] In this embodiment, the temperatures of the sealed material tank 2 and the gas pipeline 4 at the front end of the air inlet are set at 185℃±1℃ respectively, and constant temperature insulation is performed, with the temperature change required to be less than 1℃.

[0023] Step 4: When starting the preform deposition reaction, helium gas is introduced into the sealed container 2. The flow rate of helium gas is controlled within the range of 120 ml / min to 200 ml / min. In this embodiment, the flow rate of helium gas is 150 ml / min. The helium gas passes through a gas pipeline with a heating area of ​​80 cm ± 10 cm. In this embodiment, the gas pipeline with the heating area is designed to be 80 cm. The hot helium gas enters the heated sealed container 2 through the gas inlet at the upper end of the sealed container 2. When the hot helium gas flows, it carries the sublimated erbium and cerium rare earth ion chelate mixture into the quartz reaction tube 8 through the feed pipe 7 equipped with a heating device.

[0024] The vaporized rare earth ion chelate mixture flows through He gas carrier gas, exits through outlet 6, and enters feed pipe 7. The temperature of feed pipe 7 is set at 190±1℃ and maintained at a constant temperature. The rare earth ion chelate mixture is then conveyed through feed pipe 7, which is equipped with a heating device, into quartz reaction tube 8. The rare earth ion chelate mixture entering quartz reaction tube 8 begins the preform deposition reaction.

[0025] Step 5: After the preform deposition reaction is completed, the preform is shrunken and collected to obtain an erbium rare earth ion and cerium rare earth ion co-doped optical fiber preform (core diameter 1.8 mm, length 400 mm).

[0026] The carrier gas He enters the sealed material tank 2 through the inlet 3. A heating belt 5 is wrapped around the gas pipeline 4 80cm from the front end of the inlet 3. The temperature of the heating belt 5 is set to 185℃ to heat the carrier gas entering the sealed material tank 2, thereby vaporizing the rare earth chelate mixture.

[0027] This invention mixes two rare earth ion raw materials in a designed ratio and loads them into the same tank. The mixture is then vaporized by high-temperature heating, and hot helium is used as a carrier gas to carry the sublimated rare earth raw materials into a quartz reaction tube.

[0028] The fabrication process of other rare earth ion co-doped optical fiber preforms can refer to the above embodiments. The rare earth ion chelates to be co-doped are mixed in the designed proportion, and other operations are the same as those in the above embodiments.

Claims

1. A method for preparing an optical fiber preform co-doped with erbium rare earth ions and cerium rare earth ions, characterized in that, The preparation steps are as follows, using a mixture of erbium and cerium rare earth ion chelates as raw materials: Step 1: Mix a certain amount of erbium rare earth ion chelate and cerium rare earth ion chelate in a ratio of 1:3 to 1:7; Step 2: Spread the mixed erbium rare earth ion chelate and cerium rare earth ion chelate evenly on the material tray and put them into the sealed material tank; the upper end of the sealed material tank is equipped with an air inlet and the lower end of the sealed material tank is equipped with an air outlet; the gas pipeline at the front end of the air inlet and the sealed material tank are equipped with heating devices. Step 3: Heat the sealed material tank and the gas pipeline at the front end of the air inlet to 180℃-200℃ respectively; Step 4: When starting the preform deposition reaction, helium gas is introduced into the sealed container. The helium gas passes through a gas pipeline with a heating zone of 80cm±10cm and enters the sealed container through the gas inlet at the top of the container. As the hot helium gas flows, it carries the sublimated erbium rare earth ion chelate and cerium rare earth ion chelate mixture into the quartz reaction tube through a feed pipe equipped with a heating device. The flow rate of the helium gas is controlled within the range of 120ml / min-200ml / min. The temperature of the feed pipe is set at 190℃±1℃ and kept at a constant temperature. Step 5: After the preform deposition reaction is completed, the preform is shrunken and collected to obtain an erbium rare earth ion and cerium rare earth ion co-doped optical fiber preform.

2. The method for preparing an erbium rare earth ion and cerium rare earth ion co-doped optical fiber preform according to claim 1, characterized in that, In step one, erbium rare earth ion chelates and cerium rare earth ion chelates are mixed in a ratio of 1:

4.

3. The method for preparing an erbium rare earth ion and cerium rare earth ion co-doped optical fiber preform according to claim 1, characterized in that, In step three, the temperatures of the sealed material tank and the gas pipeline before the air inlet are set at 185℃±1℃ and kept at a constant temperature.

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