TWI419854B - The preparation method of the optical fiber, the preform for the fiber drawing and the mold group for making the preform for the fiber - Google Patents

Description

Optical fiber manufacturing method, preform for optical fiber drawing, and mold set for preparing optical fiber drawing preform

The present invention relates to an optical fiber drawing technique, and more specifically to a method for producing an optical fiber, a preform for optical fiber drawing, and a mold set for fabricating a preform for optical fiber drawing.

Press, "Fiber" is the full name of optical fiberglass, a fiber medium that delivers light. The structure of the optical fiber is round and thin as a fiberglass of hair, which is mainly divided into two parts, the inner layer is called core and the outer layer is called clad. Since the core diameter of the fiber is only a few "microns" (millionths of a meter) to tens of "micrometers", and the diameter of the fiber shell is only between one hundred and two hundred "micrometers", it is quite fragile. In general applications, a layer of plastic is applied to the outer layer and a layer of nylon is added to protect it from external chemicals.

Generally, there are two main methods for fabricating optical fibers. One is a light stick method, that is, a glass rod is prefabricated, and continuous drawing is performed without using a crucible, and the other is a rod tube method, that is, an inner rod is first prepared. With an outer tube, the inner rod is inserted into the outer tube and melted into a shape, and the fiber is drawn by using a crucible without using a crucible.

Although the pre-extrusion method is currently the main method of optical fiber, the optical bar method continuously draws the optical fiber, and once the fiber is started, the glass component cannot be changed, and the properties of the fiber core and the fiber shell need to be strictly matched, and the rod The pipe method needs to separately form the inner bar and the outer pipe, and then insert the inner bar into the outer pipe to form a shape and then draw the wire. The process is complicated, and it is obvious that the two kinds of optical fiber methods have to be improved.

The main object of the present invention is to provide a method for producing an optical fiber, a preform for optical fiber drawing, and a mold for fabricating a preform for optical fiber drawing, which effectively and rapidly change the properties of the optical fiber, and for the properties of the fiber core and the fiber shell The matching requirements are low, the process is simple, and the practical value is very good.

In order to achieve the foregoing object, the present invention provides a method for fabricating an optical fiber, comprising: fabricating a preform: respectively forming a glass rod and a glass shell open at one end, and placing the glass rod in a glass housing Forming a preform; spinning: using the preform to perform spinning to obtain an optical fiber.

Further, in the step of fabricating the preform, the glass rod and the glass casing are separately formed by using a first mold and a second mold.

Further, the first mold comprises a tubular cavity open at one end, the glass rod is formed by melting a glass material and poured into a cavity, and the second mold comprises a half-shell cavity open at one end for supplying the glass material. After being melted and poured, it is formed into a semi-shell-shaped glass casing, and the glass shells which are half-shell-shaped are butted to form a glass shell which is open at one end.

Further, in the step of spinning, the two-shell-shaped glass shell-coated glass rod is placed in a platinum crucible for spinning, and an optical fiber is produced.

Further, the glass rod is a glass having a higher refractive index, and the glass shell having a lower half-shell shape is a glass having a lower refractive index.

In addition, the present invention further provides a preform for optical fiber drawing, comprising a glass casing, and a cylindrical casing having an open end for drawing a fiber-shell of the optical fiber; a glass rod placed The inside of the glass casing is used for drawing to form the core of the optical fiber.

Further, the glass casing is composed of a half-shelled glass casing butted.

Further, the glass shell is a tellurite glass, which is a phosphate glass.

Furthermore, the present invention also provides a mold set for fabricating a preform for optical fiber drawing, comprising a first mold comprising a tubular cavity open at one end for forming a glass rod; and a second mold comprising an opening at one end A half-shell cavity for forming a half-shell glass casing.

Further, the first mold is composed of a left half shell and a right half shell, and the left and right half shells respectively have corresponding one-length elongated recesses, and the two concave systems correspond to form a tubular cavity. The second mold is composed of a mold base and a mold cover, and the mold base is provided with a semi-cylindrical groove, and the mold cover is provided with a semi-cylindrical rib on one side of the groove. The outer diameter of the rib is smaller than the inner diameter of the groove, and the gap between the groove and the rib forms a cavity when the die holder and the die cover are oppositely closed.

In the following, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. Referring to the drawings, a preferred embodiment of the present invention is directed to the first step 110. Forming a preform 10: the preform 10 is formed by a mold comprising a glass rod 12 and a cylindrical glass casing 14 open at one end, the mold set comprising a first mold 22 and a The second mold 24 is composed of a left half shell 26 and a right half shell 28, and the left and right half shells 26, 28 are respectively provided with corresponding two elongated recesses 30, 32. The two recesses 30 and 32 are correspondingly formed into a tubular cavity. The second die 24 is composed of a die holder 34 and a die cover 36. The die holder 34 is provided with a semi-cylindrical recess 38. The mold cover 36 is provided with a semi-cylindrical rib 40 on one side of the groove 38. The outer diameter of the rib 40 is smaller than the inner diameter of the groove 38, and the mold base 34 is opposite to the mold cover 36. The gap between the groove 38 and the rib 40 forms a cavity.

The glass rod 12 is a glass having a higher refractive index, and is formed by melting a phosphate glass material and pouring it into a cavity of the first mold 22, and the glass housing 14 is made of a glass having a lower refractive index. The acid salt glass material is melted and poured into the cavity of the second mold 24, and the crucible can be formed into a semi-shell-shaped glass casing 42 (44), and then the two half-shell glass casings 42, 44 are butted to form the glass. Housing 14.

The second step 120 of the present invention is to draw the wire: after the glass rod 12 is placed in the glass casing 14 formed by the glass shell of the two-shelled shell, the preform 10 is formed, and then the preform 10 is placed into a In the platinum crucible of the fiber drawing device (not shown), the preform 10 can be used for spinning to obtain an optical fiber. That is, the glass rod 12 forms a core of an optical fiber, and the glass casing 14 forms a fiber shell of the optical fiber.

As can be seen from the above, the optical fiber manufacturing method, the preform for the optical fiber drawing, and the mold group for preparing the optical fiber drawing preform are respectively prepared, and the glass rod 12 and the glass casing 14 are respectively formed into the preform 10 The preform 10 can be used for spinning to form an optical fiber. By making the glass rod 12 and the glass casing 14 separately, the glass composition of the glass rod 12 or the glass casing 14 can be quickly and conveniently replaced by the requirements of the properties of the optical fiber, thereby changing the properties of the optical fiber.

In other words, the present invention can effectively and quickly change the properties of the optical fiber, and has low matching requirements for the properties of the core and the shell, and requires continuous extraction of the optical fiber for a long time compared with the conventional light bar method, and the fiber is initially drawn. The contained glass component cannot be changed, and the properties of the core and the shell need to be strictly matched. It is obvious that the invention has more practical value. Furthermore, the process of the present invention is obviously simpler and more complicated than the conventional bar tube method in which the inner bar and the outer tube are separately formed, and the inner bar is inserted into the outer tube to form a shape and then drawn. practical.

10. . . Preform

12. . . Glass bar

14. . . Glass housing

twenty two. . . First mold

twenty four. . . Second mold

26. . . Left half shell

28. . . Right half shell

30, 32. . . Concave

34. . . Mold base

36. . . Mold cover

38. . . Groove

40. . . Rib

42, 44. . . Glass housing

110. . . Making a preform

120. . . Snagging

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a flow chart of a preferred embodiment of the present invention.

Figure 2 is a schematic view showing the combination of preforms according to another preferred embodiment of the present invention.

Figure 3 is an exploded perspective view of a preform of another preferred embodiment of the present invention.

Figure 4 is an exploded perspective view of the first mold in the mold set of still another preferred embodiment of the present invention.

Figure 5 is a perspective exploded view of a second mold in a mold set according to still another preferred embodiment of the present invention.

110. . . Making a preform

120. . . Snagging

Claims (8)

A method for manufacturing an optical fiber, the method comprising the steps of: fabricating a preform: using a first mold and a second mold, respectively fabricating a glass rod and a glass shell open at one end, and placing the glass rod in the glass Forming a preform for fiber drawing inside the casing; and spinning: using the preform to perform drawing to obtain an optical fiber. The method for manufacturing an optical fiber according to claim 1, wherein the first mold comprises a tubular cavity open at one end, and the glass rod is formed by melting a glass material and pouring into a cavity, the second mold comprising an opening at one end. The half-shell-shaped cavity is used for forming a glass shell of a half-shell shape after the glass material is melted and poured, and the glass shell of the one end is formed by abutting the glass shell of the half-shell shape. The method for manufacturing an optical fiber according to claim 2, wherein in the step of spinning, the two-shell-shaped glass shell-coated glass rod is placed in a platinum crucible for spinning. Into the fiber. The method for producing an optical fiber according to claim 3, wherein the glass rod is a glass having a higher refractive index, and the glass shell having a lower half shell shape is a glass having a lower refractive index. A preform for fiber drawing, comprising: a glass casing, which is generally a cylindrical casing open at one end, which is composed of a half-shell-shaped glass casing but is connected to form a fiber-shell of the optical fiber; and a glass rod is placed on the glass The inside of the casing is used for drawing to form the core of the optical fiber. The preform for optical fiber drawing according to claim 5, wherein the glass shell is a glass having a lower refractive index, and the glass rod is a glass having a higher refractive index. A mold set for fabricating a preform for optical fiber drawing, comprising: a first mold comprising a tubular cavity open at one end for molding a glass rod; and a second mold comprising a half shell having an open end A cavity for forming a half-shell glass casing. The mold set for preparing a preform for optical fiber drawing according to claim 7, wherein the first mold is composed of a left half shell and a right half shell, and the left and right half shells respectively have corresponding One of the strip-shaped recesses, the two recesses corresponding to the tubular forming cavity, the second mold is composed of a mold base and a mold cover oppositely covering, the mold base is provided with a semi-cylindrical groove, The mold cover has a semi-cylindrical rib on one side of the corresponding groove, and the outer diameter of the rib is smaller than the inner diameter of the groove, When the mold base and the mold cover are oppositely closed, the gap between the groove and the rib forms a cavity.