An optical fiber preform, a method for manufacturing the same, and an optical fiber

Abstract

The application discloses a kind of optical fiber preform and its preparation method, optical fiber, the optical fiber preform includes cladding glass, cladding glass is provided with through hole, through hole is constituted by first hole and second hole channel;First hole is placed with core material;The inner diameter of second hole channel is less than the outer diameter of the core material;The outer diameter of core material is less than the inner diameter of the first hole channel.The softening temperature of cladding glass used in the application is higher than the melting temperature of core material, cladding is in softening state during drawing process, and core is in melting state;The diameter of optical fiber is very thin, and the process of fast traction can cool the optical fiber quickly, so as to inhibit the uncontrollable crystallization of core melt, finally obtain the composite optical fiber with expected optical performance;Cladding glass is provided with second hole channel, effectively releases the pressure generated by glass melt, inhibits the deformation of optical fiber, bubble and the occurrence of core discontinuity problem;The core-cladding ratio of the final optical fiber can also be adjusted by adjusting the diameter of second hole channel.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of optical communication and new materials, and particularly relates to an optical fiber preform and a preparation method thereof, and an optical fiber. BACKGROUND

[0002] Optical fiber is a basic component for optical communication, optical fiber sensing, optical fiber laser and other applications. Some new applications, such as new wavelength optical fiber laser, broadband optical amplifier and the like, require the development of new type of glass optical fiber. However, many high-performance glass materials cannot be drawn into glass optical fiber meeting the requirements of practical applications through the traditional "rod-in-tube" optical fiber drawing process. The fundamental reason is that these glass materials are very easy to crystallize during heating, and in the traditional "rod-in-tube" optical fiber drawing process, both the cladding and core glasses are in a softened state, and the glass core will excessively crystallize and lose the expected optical properties, resulting in that the final optical fiber cannot be used.

[0003] In view of this problem, some researchers have proposed a "core melting" optical fiber manufacturing technology. This technology uses a glass with a higher softening temperature than the core glass as the cladding material of the optical fiber. In the optical fiber drawing process, the cladding glass is in a softened state, while the core is in a molten state. Even if the core material crystallizes severely during heating, the generated crystals can be re-melted at the drawing temperature. During the drawing process, the optical fiber is quickly pulled out of the furnace of the drawing tower, and the diameter of the optical fiber is very small, so it will be quickly cooled, thereby inhibiting the uncontrollable crystallization of the core glass, and finally obtaining a glass optical fiber with expected optical properties. In combination with subsequent heat treatment at a lower temperature, nanocrystals with special functions can be controllably precipitated in the optical fiber, thereby improving the performance of the optical fiber or even obtaining new functions. This method can even draw non-glass materials (such as crystals, metals, etc.) that do not have drawing performance into composite fibers. Through the "core melting" method, researchers have realized the controllable preparation of many special functional composite optical fibers, including microcrystalline glass composite glass optical fiber, semiconductor core composite glass optical fiber, metal core composite glass optical fiber and the like.

[0004] Although the "core melting" method has been successful in the manufacture of special glass optical fibers, there is still a serious technical problem: because the core glass is in a molten state during the drawing process, the glass melt will exert a certain extrusion on the cladding glass, resulting in deformation of the optical fiber structure or even the generation of bubbles or core discontinuity. This condition is particularly serious when the core material contains a large amount of volatile components. Therefore, the "core melting" method often has difficulty in accurately controlling the geometric structure and quality of the optical fiber, which seriously affects its actual application. The present application proposes an improved "core melting" optical fiber manufacturing technology to solve the technical problems of the traditional "core melting" optical fiber manufacturing technology, such as difficulty in accurately controlling the geometric structure of the optical fiber and easy generation of bubbles and core discontinuity. SUMMARY

[0005] The present application aims at solving the problems of the prior art, and provides an optical fiber preform, a preparation method thereof and an optical fiber.

[0006] The present application aims at solving the problems of the prior art, and provides an optical fiber preform, a preparation method thereof and an optical fiber.

[0007] Further, the softening temperature of the cladding glass is greater than the melting temperature of the core material.

[0008] Further, the cladding glass is silicate glass, germanate glass, tellurite glass, bismuthate glass, phosphate glass or chalcogenide glass.

[0009] Further, the core material is glass, ceramic, crystal, metal or plastic.

[0010] Further, the outer diameter of the cladding glass is 30-50 mm; the inner diameter of the first hole is 1.0-20.0 mm; the inner diameter of the second hole is 0.5-15.0 mm; and the outer diameter of the core material is 0.8-19.5 mm.

[0011] A preparation method of the optical fiber preform is provided, which comprises the following steps: opening a through hole in cladding glass; the through hole is composed of two holes with different diameters, which are a first hole and a second hole; placing a core material in the first hole to form an optical fiber preform; the inner diameter of the second hole is smaller than the outer diameter of the core material; and the outer diameter of the core material is smaller than the inner diameter of the first hole.

[0012] An optical fiber is prepared by the following method:

[0013] (1) fixing the optical fiber preform or the prepared optical fiber preform at the first hole end on a preform clamping device of a fiber drawing tower, and adjusting the height of the optical fiber preform through a lifting device;

[0014] (2) then heating the drawing tower electric furnace to a drawing temperature; wherein the drawing temperature is greater than the softening temperature of the cladding glass;

[0015] (3) softening the end of the optical fiber preform close to the second hole, and then starting to draw the optical fiber; wherein the optical fiber preform is lowered through the lifting device during the drawing.

[0016] Further, the drawing speed of the optical fiber is 5-50 mm / s.

[0017] Further, the optical fiber preform is dropped at a speed of 0.5-5.0 mm / min.

[0018] Further, the core-cladding ratio of the optical fiber is controlled by adjusting the inner diameter of the second hole in the cladding glass.

[0019] The present application has the following advantages:

[0020] 1. The cladding glass used in the present application has a softening temperature higher than the melting temperature of the core material, so that the cladding is in a softened state and the core is in a molten state during the drawing process. The ultra-fine diameter of the optical fiber and the rapid drawing process can allow the optical fiber to cool rapidly, thereby inhibiting uncontrollable crystallization of the core melt, and ultimately obtaining a composite optical fiber with the desired optical properties.

[0021] 2. The cladding glass of the present application is provided with a second hole (pressure relief hole) which can effectively release the pressure generated by the glass melt, thereby inhibiting the occurrence of deformation, bubbling and core discontinuity of the optical fiber.

[0022] 3. The present application can control the core-cladding ratio of the final optical fiber by adjusting the diameter of the second hole (pressure relief hole). BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0024] Figure 1 Figure 1 is a schematic diagram of the structure of an optical fiber preform;

[0025] Figure 2 Figure 2 is a schematic diagram of the optical fiber drawing process;

[0026] Figure 3 Figure 1 is a digital photograph of an optical fiber preform; Figure 2 is a scanning electron microscope photograph of the cross-section of an optical fiber; Figure 3 is an optical microscope photograph of the cross-section of an optical fiber. DETAILED DESCRIPTION

[0027] The various exemplary embodiments of the present application will now be described in detail, which should not be considered as limiting the present application, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present application. It should be understood that the terms described in the present application are only for the description of the particular embodiments, and are not intended to limit the present application.

[0028] In addition, for numerical ranges of the present application, it is intended that every intermediate value of the upper and lower limits of the range in addition to the upper and lower limits are specifically included. Each smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in that stated range is also encompassed. The upper and lower limits of these smaller ranges can independently be included or excluded in the range.

[0029] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned herein are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are cited. In case of conflict, the content of the present specification will control.

[0030] Many modifications and variations of the present application described in the specific embodiments of the application can be made by those skilled in the art without departing from the spirit or scope of the application. Other implementations of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application. The specification and examples are illustrative only.

[0031] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having", "contains", "containing", or variations thereof, are intended to be open-ended terms that mean including, but not limited to.

[0032] Example 1:

[0033] A kind of optical fiber of the present application, core layer material is phosphorus-bismuthate glass;Cladding glass is silicate glass, this embodiment uses commercial K9 glass, the following preparation method is obtained:

[0034] (1) the phosphorus-bismuthate glass is polished into glass rod with length of 10 cm and diameter of 2 mm, and its surface is polished. The glass rod is used as optical fiber preform rod core layer material;

[0035] The phosphorus-bismuthate glass is bulk glass prepared by melt quenching method, and its chemical composition is 50P2O5-16Bi2O3-30ZnO-4Al2O3(mol%), T g (glass transition temperature), T x (crystallization temperature) and T m (melting temperature) are 430℃, 571℃ and 762℃ respectively;

[0036] (2) Using a drill press, a through hole is drilled in the center of a commercial K9 glass rod with a length of 20 cm and a diameter of 3 cm. The hole is composed of two sections with diameters of 1 mm and 2.2 mm, and lengths of 10 cm. The hole with a diameter of 2.2 mm is the first hole, and the hole with a diameter of 1 mm is the second hole (pressure relief hole);

[0037] (3) The phosphorus-bismuth glass rod of step (1) is inserted into the hole with a diameter of 2.2 mm of the K9 glass rod of step (2) to obtain a fiber preform rod, as shown in FIG. (a) of Figure 3 ;

[0038] (4) The upper end of the fiber preform rod of step (3) (the end with the phosphorus-bismuth glass rod inserted) is fixed on a fiber drawing tower preform rod clamping device, and the height of the preform rod is adjusted to an appropriate position by a lifting device. Then the drawing tower electric furnace is heated to a drawing temperature (930°C), and after the lower end of the preform rod is heated and softened, it is stretched and drawn to form an optical fiber, as shown in FIG. (b) of Figure 2 ; Figure 3 FIG. (b) is a scanning electron microscope photograph of the cross section of the optical fiber, Figure 3 FIG. (c) is an optical microscope photograph of the cross section of the optical fiber. The preform rod lowering speed and the optical fiber drawing speed are 1 mm / min and 20 mm / s, respectively.

[0039] Example 2:

[0040] The same as Example 1, except that in this example, the diameter of the pressure relief hole of the cladding glass in step (2) is 0.5 mm.

[0041] Example 3:

[0042] The same as Example 1, except that in this example, the preform rod lowering speed and the optical fiber drawing speed in step (4) are 0.5 mm / min and 5 mm / s, respectively.

[0043] Example 4:

[0044] The same as Example 1, except that in this example, the diameter of the core glass rod in step (1) is 3 mm, and the diameters of the thicker section of the through hole and the pressure relief hole of the cladding glass in step (2) are 3.2 mm and 1.5 mm, respectively.

[0045] Example 5:

[0046] The same as Example 1, except that in this example, the diameter of the core glass rod in step (1) is 5 mm, and the outer diameter of the cladding glass rod in step (2) is 3.5 cm, and the diameters of the thicker section of the through hole and the pressure relief hole are 5.2 mm and 2.5 mm, respectively.

[0047] Example 6:

[0048] The same as example 1, except that in this example, the step (1) core layer glass rod diameter is 19.5 mm, the step (2) cladding layer glass rod outer diameter is 5 cm, the through hole thicker section and pressure relief hole diameter are 20 mm and 15 mm respectively, and the step (4) lowering speed and optical fiber pulling speed are 5.0 mm / min and 50 mm / s respectively.

[0049] Example 7:

[0050] An optical fiber of the present application, the core layer material is metal material, and a commercial tin rod is used in this example; the cladding layer glass is silicate glass, and a commercial K5 glass is used in this example, which is obtained by the following preparation method:

[0051] (1) A through hole is processed in the center of a commercial K5 glass rod with a length of 20 cm and a diameter of 3 cm by using a drilling machine. The hole is composed of two sections with diameters of 1 mm and 2.2 mm and lengths of 10 cm respectively; the hole with a diameter of 2.2 mm is the first hole, and the hole with a diameter of 1 mm is the second hole (pressure relief hole);

[0052] (2) A commercial tin rod with a length of 10 cm and a diameter of 2 mm is inserted into the first hole in the commercial K5 glass rod to obtain an optical fiber preform rod.

[0053] (3) The upper end (the end with the tin rod inserted) of the optical fiber preform rod obtained in step (2) is fixed on the preform rod clamping device of the optical fiber drawing tower, and the height of the preform rod is adjusted to an appropriate position by the lifting device. Then the drawing tower electric furnace is heated to the drawing temperature (900℃), and after the lower end of the preform rod is heated and softened to neck and stretch, the drawing is started, and an optical fiber is prepared, with the preform rod lowering speed and the optical fiber pulling speed being 1 mm / min and 20 mm / s respectively.

[0054] Example 8:

[0055] The same as example 7, except that in this example, the step (1) core layer tin rod diameter is 0.8 mm, and the step (2) cladding layer glass through hole thicker section and pressure relief hole diameter are 1.0 mm and 0.5 mm respectively.

[0056] Example 9:

[0057] The same as example 7, except that in this example, the tin rod used in step (2) is replaced by a lead rod of the same size.

[0058] Example 10:

[0059] The same as example 7, except that in this example, the tin rod used in step (2) is replaced by a zinc rod of the same size.

[0060] Example 11:

[0061] The same as example 7, except that the tin rod used in step (2) is replaced by a commercial low-melting-point silver-copper filler (GB-Ag72Cu) of the same size in this example.

[0062] Example 12:

[0063] The same as example 7, except that the tin rod used in step (2) is replaced by a commercial low-melting-point copper-phosphorus filler (P7Cu93) of the same size in this example.

[0064] Example 13:

[0065] A fiber according to the present application, the core material is a semiconductor, and bismuth telluride is used in this example; the cladding glass is silicate glass, and commercial Pyrex glass is used in this example, which is obtained by the following preparation method:

[0066] (1) A through hole is processed at the center position of a commercial Pyrex glass (composition: 80.5SiO2-13.2B2O3-4.0Na2O-2.3Al2O3, mol%) rod with a length of 20 cm and a diameter of 3 cm. The hole is composed of two sections with diameters of 1 mm and 2.2 mm, and lengths of 10 cm; among them, the hole with a diameter of 2.2 mm is the first hole, and the hole with a diameter of 1 mm is the second hole (pressure relief hole);

[0067] (2) A bismuth telluride (Bi2Te3) rod with a length and diameter of 10 cm and 2 mm is inserted into the first hole in the commercial Pyrex glass rod to obtain a fiber preform rod;

[0068] (3) The upper end (the end with the bismuth telluride rod inserted) of the fiber preform rod obtained in step (2) is fixed on the fiber drawing tower preform rod clamping device, and the height of the preform rod is adjusted to the appropriate position by the lifting device. Then the drawing tower electric furnace is heated to the drawing temperature (900℃), as shown in FIG. 1, and after the lower end of the preform rod is heated and softened, it is stretched and drawn to form a fiber. The preform rod lowering speed and the fiber drawing speed are 1 mm / min and 20 mm / s, respectively. Figure 2

[0069] Example 14:

[0070] The same as example 13, except that the bismuth telluride rod used in step (2) is replaced by a bismuth selenide (Bi2Se3) rod of the same size in this example.

[0071] Example 15:

[0072] The same as example 13, except that the bismuth telluride rod used in step (2) is replaced by a bismuth (Bi) rod of the same size in this example, and the drawing temperature used in step (3) is changed to 860℃. ​

[0073] Example 16:

[0074] The same as example 13, except that in this example the bismuth telluride rod used in step (2) is replaced with an indium selenide (In4Se3) rod of the same size.

[0075] Example 17:

[0076] The same as example 13, except that in this example the Pyrex glass rod with a hole used in step (1) is replaced with a K9 glass rod with a hole of the same size, the bismuth telluride rod used in step (2) is replaced with a germanium selenide (GeSe) rod of the same size, and the drawing temperature used in step (3) is adjusted to 950°C.

[0077] A fiber preform according to the present application, as shown in FIG. 1, includes a cladding glass, the cladding glass is provided with a through hole, the through hole is composed of a first hole and a second hole; the first hole is placed with a core material; the inner diameter of the second hole is smaller than the outer diameter of the core material; the outer diameter of the core material is smaller than the inner diameter of the first hole. Wherein, the softening temperature of the cladding glass is greater than the melting temperature of the core material. Figure 1

[0078] In some embodiments, the cladding glass is a silicate glass, a germanate glass, a tellurite glass, a bismuthate glass, a phosphate glass, or a chalcogenide glass.

[0079] In some embodiments, the core material is a glass, a ceramic, a crystal, a metal, or a plastic.

[0080] In some embodiments, the outer diameter of the cladding glass is 30-50 mm; the inner diameter of the first hole is 1.0-20.0 mm; the inner diameter of the second hole is 0.5-15.0 mm; and the outer diameter of the core material is 0.8-19.5 mm.

[0081] The above description is merely preferred embodiments of the application, but the protection scope of the application is not limited to this. Any person skilled in the art, according to the technical solution and the inventive concept of the application, can make equivalent replacements or changes within the technical range disclosed by the application, which should be covered by the protection scope of the application.​

Claims

1. An optical fiber preform, characterized by, The cladding glass is provided with a through hole composed of a first hole and a second hole; the first hole is placed with a core material; the inner diameter of the second hole is smaller than the outer diameter of the core material; the outer diameter of the core material is smaller than the inner diameter of the first hole. The softening temperature of the cladding glass is greater than the melting temperature of the core material.

2. A fiber preform as claimed in claim 1, wherein, The cladding glass is silicate glass, germanate glass, tellurite glass, bismuthate glass, phosphate glass or chalcogenide glass.

3. A fiber preform as claimed in claim 1, wherein, The core material is glass, ceramic, crystal, metal or plastic.

4. A fiber preform as claimed in claim 1, wherein, The outer diameter of the cladding glass is 30-50 mm; the inner diameter of the first hole is 1.0-20.0 mm; the inner diameter of the second hole is 0.5-15.0 mm; and the outer diameter of the core material is 0.8-19.5 mm.

5. A method of producing the optical fiber preform according to any one of claims 1 to 4, characterized by, The cladding glass is opened a through hole; the through hole is composed of two holes with different diameters, which are the first hole and the second hole respectively; the core material is placed in the first hole, thereby forming an optical fiber preform; the inner diameter of the second hole is smaller than the outer diameter of the core material; and the outer diameter of the core material is smaller than the inner diameter of the first hole.

6. An optical fiber, characterized by, The optical fiber preform is prepared by the following method: (1) fixing the optical fiber preform of claim 1 or the optical fiber preform prepared by claim 5 at the end close to the first hole on the optical fiber drawing tower preform clamping device, and adjusting the height of the optical fiber preform by the lifting device; (2) then heating the drawing tower electric furnace to a drawing temperature; wherein the drawing temperature is greater than the softening temperature of the cladding glass; (3) the end of the optical fiber preform close to the second hole is softened and then starts to be drawn to form an optical fiber; wherein during the drawing, the optical fiber preform is lowered by the lifting device.

7. An optical fiber as claimed in claim 6, characterized in that The drawing speed of the optical fiber is 5-50 mm / s.

8. An optical fiber as claimed in claim 6, characterized in that The lowering speed of the optical fiber preform is 0.5-5.0 mm / min.

9. An optical fiber as claimed in claim 6, characterized in that, The core-cladding ratio of the optical fiber is controlled by adjusting the inner diameter of the second hole in the cladding glass. The cladding glass is provided with a through hole composed of a first hole and a second hole; the first hole is placed with a core material; the inner diameter of the second hole is smaller than the outer diameter of the core material; the outer diameter of the core material is smaller than the inner diameter of the first hole. The softening temperature of the cladding glass is greater than the melting temperature of the core material. The cladding glass is silicate glass, germanate glass, tellurite glass, bismuthate glass, phosphate glass or chalcogenide glass. The core material is glass, ceramic, crystal, metal or plastic. The outer diameter of the cladding glass is 30-50 mm; the inner diameter of the first hole is 1.0-20.0 mm; the inner diameter of the second hole is 0.5-15.0 mm; and the outer diameter of the core material is 0.8-19.5 mm. The cladding glass is opened a through hole; the through hole is composed of two holes with different diameters, which are the first hole and the second hole respectively; the core material is placed in the first hole, thereby forming an optical fiber preform; the inner diameter of the second hole is smaller than the outer diameter of the core material; and the outer diameter of the core material is smaller than the inner diameter of the first hole. The optical fiber preform is prepared by the following method: (1) fixing the optical fiber preform of claim 1 or the optical fiber preform prepared by claim 5 at the end close to the first hole on the optical fiber drawing tower preform clamping device, and adjusting the height of the optical fiber preform by the lifting device; (2) then heating the drawing tower electric furnace to a drawing temperature; wherein the drawing temperature is greater than the softening temperature of the cladding glass; (3) the end of the optical fiber preform close to the second hole is softened and then starts to be drawn to form an optical fiber; wherein during the drawing, the optical fiber preform is lowered by the lifting device. The drawing speed of the optical fiber is 5-50 mm / s. The lowering speed of the optical fiber preform is 0.5-5.0 mm / min. The core-cladding ratio of the optical fiber is controlled by adjusting the inner diameter of the second hole in the cladding glass.

Images