JP2003322773A - Structure of heat-resisting and high-strength optical fiber and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for easily manufacturing an optical fiber, which is made free of problems even under very severe conditions at home, in an automobile, etc., by greatly improving the mechanical strength and heat resistance of a ceramic-based optical fiber continuously with high productivity by employing an electroforming method for a main process. <P>SOLUTION: In the method, one or more metal layer 3 are deposited by an electroforming method directly on the clad part of an optical fiber or on the core part of a coated optical fiber. By employing a relatively soft material for the metal layers and making the metal not too thick a fatal defect such as the breaking of the fiber is completely prevented. Further, a means of providing a gap for a tube made of SUS upon occasion is employed and furthermore a means of preventing the breaking due to an impact force and imparting heat resistance, etc., is employed. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel structure of a ceramic optical fiber used for optical communication and the like and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a ceramic optical fiber is composed of a core portion 1 and a clad portion 2, as generally shown in FIG. 1. This is generally called an optical fiber element wire, and the clad has a core portion. By using a material having a lower refractive index than that, light propagates in the transparent core portion 1 at the speed of light while repeating total reflection as shown in FIG. 2, and silica glass or multi-component glass is used as a material. There is an optical fiber used for.

The optical fiber strand is specified in JIS standard, and for example, a silica-based multimode optical fiber strand C-
6832: 1999, multi-component multimode optical fiber strand C-6833: 1999, silica single mode optical fiber strand C-6835: 1999, etc., and core diameters are 7 μm, 8 μm, 9 μm, 9.3 μm, 10.5
.mu.m, 50 .mu.m, 62.5 .mu.m, etc., and the cladding outer diameter is 125 .mu.m, 140 .mu.m, 220 .mu.m, 2
There are many types such as 30 μm and 250 μm.

Since all of these ceramic optical fiber strands use a structure in which a transparent material having a refractive index lower than that of the core is used for the clad, there is a problem of optical loss when bent strongly. Also, since the silica and multi-component glass used have the basic properties of being hard and brittle, bending and impact are extremely weak, and the surface is scratched. There are serious problems such as natural breakage due to changes over time, and it becomes even weaker in the presence of water.Therefore, as a countermeasure against these problems, a plastic is coated to form a core wire for the purpose of reinforcing the optical fiber element wire. Although it is reinforced with a tensile strength body, sheath, etc., since plastic is used for all of this reinforcing material, it lacks elastic strength and mechanical strength such as bending. If it is used in a portion where external force such as a bending force is applied, it may cause a fatal defect such as a broken fiber, which poses a problem for home use, and its heat resistance is extremely weak. There was a problem that it could not be used at all under severe conditions such as high heat and vibration.

As a solution to these problems, the present inventor has filed a patent application 20.
No. 01-290096 proposes a method of directly and continuously electroforming an optical fiber element wire or an optical fiber core wire in an extremely long state, but in the patent, the hardness of the electroformed metal is proposed. Although the thickness is not limited, for example, when using a silica-based or multi-component ceramic optical fiber, when an electroformed metal that is hard, has little elongation, and has a large linear expansion coefficient is deposited extremely thickly, In some cases, due to the large stress that clamps the optical fiber at extremely low temperatures, a problem such as a fatal failure in which the optical fiber breaks may occur.

[0006]

In view of the above, the present invention has been made.
A large stress that tightens the optical fiber due to the difference in the coefficient of linear expansion at low temperature when electroforming a thick metal for the purpose of improving the heat resistance by electroforming the optical fiber and at the same time increasing the strength independently. Solves the fatal problem that the optical fiber breaks, and solves the problem that the optical fiber breaks even if a large physical force such as impact or bending is applied, and It can be used under extremely severe conditions such as the environment, and if necessary, it can completely reduce the loss of light due to strong bending, and the thickness and concentricity are controlled accurately. An object of the present invention is to provide a method for easily and inexpensively supplying an optical fiber.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a ceramic-based optical fiber element wire or an optical fiber core portion (since there is no such wire in the current market, (Provisionally referred to as "optical fiber core wire") directly deposits or reinforces one or more metal layers formed by electroforming, and the metal deposited at that time uses a relatively soft material, By not making the metal too thick, we have adopted a means to relieve the tightening stress when the temperature drops and completely prevent the occurrence of fatal defects such as breakage of the optical fiber. Improving the uniformity of the metal thickness to improve the concentricity of the electroformed part and the optical fiber part, the electroformed optical fiber in the hole of the ferrule,
It can be inserted and used as it is, and depending on the case, it may be a gap in a strong tube such as SUS or resin with a slightly thicker hole than the thickness of the electroformed optical fiber element wire or core wire. By adopting a means for providing and storing, it is possible to prevent breakage due to tensile force and impact force and to provide heat resistance and electrical insulation, etc., and further adopt a method of electroforming directly on the optical fiber core wire By doing so, it became possible to completely eliminate the loss of light due to strong bending.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION To explain the embodiments of the present invention in more detail, in order to deposit a metal directly on an elemental wire of an optical fiber or a core wire by an electroforming method, the conductivity is poor on the surface, An electrification treatment is required, and any known dry method or wet method can be adopted as the method.

As the dry method, for example, a method of depositing a relatively soft metal such as aluminum, nickel or copper with a thickness of about several tens of angstroms to several tens of μm by vacuum deposition, sputtering, ionization plating or the like can be adopted. As the wet method, silver mirror reaction, electroless plating of copper, nickel, etc., or coating with conductive paint can be adopted.
In this case, since electroforming is performed on the entire surface around the optical fiber, there is a phenomenon that problems such as peeling are unlikely to occur even if adhesion is poor, so there is an advantage that any method may be adopted, In particular, since the dry sputtering method has good adhesiveness, it is economical because it can be made extremely thin and can be manufactured in a short time.
Further, since the throwing power is good, it is suitable in terms of the uniformity of electrical conductivity and the resulting uniformity of the electroformed film thickness. This method is, for example, as shown in FIG.
The inside of the chamber is first made into a high vacuum state, then an inert gas such as argon gas is appropriately introduced into a controlled state, a high-voltage current is passed, and ions generated by high-density plasma strike the metal to be deposited, A metal atom with high energy is fixed on the surface of the object to be coated, forming a high-quality metal film. The targets (metal plates to be formed) are placed facing each other, and the object to be coated is in the middle. The long-wound optical fiber 9 is introduced into the sputtering tank by a double-sided simultaneous film formation method using a pair of opposing targets 42 or a plurality of pairs of opposing targets 42, which are formed by passing them through.
The method of continuously sputtering a single layer or a plurality of layers of highly conductive metal on the extremely long optical fiber 9 while slowly winding it in conjunction with the rotating drum 43 that automatically rotates is particularly suitable. And the film thickness can be accurately controlled by the passage time of the section.

In the present invention, when the electroforming is directly performed on the optical fiber element wire and the optical fiber core wire, as shown in FIG.
As shown in (b), a metal having good conductivity such as nickel is provided on the outside of the clad portion 2 and the core portion 1 of the optical fiber.
For example, an electroformed metal layer 4 is formed by electroforming after forming an ultrathin current-carrying layer 3 having a thickness of about 50 to 200 angstroms, such as a sputtering method by a double-sided simultaneous film formation method using a facing target, and an electroformed optical fiber 5 is manufactured. To do.

First, the current-carrying layer 3 is formed by a sputtering method or the like. As the metal used at this time, a metal having good current-carrying property such as nickel, aluminum, zirconium or copper can be used, but soft chemical stability. Higher metals are desirable and nickel is particularly suitable.

In a subsequent step, electroforming is performed to perform electroforming metal layer 4
The main purpose of this electroforming is to prevent fatal defects such as tensile strength and impact strength of the ceramic optical fiber that are extremely low and easily breaks. The metal having a high stability and a relatively soft Vickers hardness, for example, in the range of about 20 to 350, particularly preferably about 200 is suitable and has a small linear expansion coefficient. Is preferable, but especially nickel, copper, which does not contain a curing agent,
Tin and lead are suitable, and nickel is particularly desirable.

FIG. 5 is a schematic configuration diagram of an embodiment of the electroforming apparatus according to the present invention. The optical fiber 9, the optical fiber receiving pulley 25, the plus electrode spring terminal 26, the minus electrode spring terminal 27, and the plus electrode rotation. The motor 28, the belt 12, the electroforming tank 10, the electroforming liquid 29, the structure 30, the metal anode 31, and the filter pump 32 are provided. The electroforming liquid 29 is put into the electroforming tank 10 and heated. The filtered and stirred conductive optical fiber 9 is received by the optical fiber receiving pulley 25, dipped in the electroforming liquid 29 in the electroforming tank 10, and is positively energized by the positive electrode spring terminal 26. The optical fiber 9 is negatively energized by the negative electrode spring terminal 27 by moving it at a constant speed from the right to the left through the vicinity of the center of the hole 33 of the metal anode 31 such as nickel. The metal anode 31 is the positive electrode rotation motor 2
8 and the belt 12 rotate around the optical fiber 9.

The metal anode 31 is arranged with the optical fiber 9 at the center and is electroformed while rotating the tubular metal anode 31 because the thickness of the electroformed portion is constant, which is very accurate. It is desirable because the concentricity can be obtained, but in some cases, there may be no problem even if the metal anode 31 does not rotate, and the metal anode 31 is tubularly separated into left and right sides in the range of about 2 to 10,
By connecting a positive electrode spring terminal 26 to each of them, it is also possible to adopt a method of starting at a low current value at the beginning and sequentially increasing the current value. By adopting this method, an ideal condition in good condition can be obtained. Enables electroforming.

For stirring, general stirring such as air, propeller, ultrasonic wave, and super vibration can be adopted. As shown in FIG. 5, the liquid flow is directed to the optical fiber at the center of the metal anode 31 by a pump such as a filter pump 32. The method of flowing near 9 is a desirable method in terms of the effect of stirring, simplicity of the apparatus, and the like.

The control of the electroformed film thickness is very important, but the current value is accurately kept constant by using a constant current device and the moving speed of the optical fiber 9 is adjusted to accurately control the electroforming time. Then, extremely accurate dimensional control can be easily performed by controlling the integrated current value.However, in the present invention, if the thickness of electroforming is too thick, under low temperature, due to the stress that strongly tightens the optical fiber, Since the phenomenon that the optical fiber breaks may occur, an electroformed thickness of about 0.01 mm to 0.4 mm is suitable as a means for preventing this phenomenon, and a thickness of about 0.1 mm is particularly preferable. Although the casting time is short, the concentricity is easily obtained, and the stress for tightening the optical fiber is small, the suitability is high, but in the present invention, the thickness is not particularly limited, and the integrated electric By accurately manage the values,
It is also possible to accurately control the thickness of the produced electroformed optical fiber.

When the metal anode 31 of the present invention is rotated, the rotation speed is about 20 to 1000 rpm. The higher the rotation speed, the more uniform the electroformed thickness. Therefore, the concentricity between the electroformed portion and the optical fiber portion is obtained. The quality can be improved such that the degree can be remarkably improved, and the electroforming is performed with a direct current at a current density of about 1 to 20 A / dm ² .

In the present invention, the electroformed optical fiber 5 manufactured as described above may be used as it is, but depending on the case, various methods as shown below can be adopted. For example, as shown in FIG. In addition, the electroformed optical fiber 5 may be housed in the metal tube 6 with a gap 7 provided therein, and the metal tube 6 used here has a rigidity that cannot be easily crushed. It is desirable that the inner electroformed optical fiber 5 has a high physical strength to such an extent that no abnormality occurs even if a large force is applied locally, and a SUS tube or phosphorus manufactured by a commercial drawing method (drawing method) is used. Bronze tubes are particularly suitable, and we employ a method of mass-producing injection needles, which is generally called a semi-seamless method, in which a plate is used as a starting material, rolled and welded, and then gradually drawn into thin tubes by a drawing method. To do It is advantageous in terms of cost.

In addition, in the case of FIG. 6, since it may be used together with an electric wire and there may be a problem with the electric insulation property, as shown in FIG. Electricity is provided by a method of providing a resin coating layer that is inflammable or non-combustible or heat-insulating in close contact, and in some cases by providing a foamed heat-resistant resin, or by providing a heat-resistant electrically insulating fiber woven layer with a gap. You may employ | adopt the structure which provides the insulating layer 8 with respect to heat.

Further, as shown in FIG. 8, the electroformed optical fiber 5 may be housed in a resin pipe 11 with a gap 7 provided therein. In this case, the resin pipe 11 is made of polyvinyl chloride. Resins with arbitrary physicochemical performance can be selected from general purpose such as polypropylene, engineering plastics such as polyester, and soft to hard ones, but rigidity, strength, flame retardancy, heat resistance , It should be selected with a view to heat insulation.

Further, as shown in FIG. 9, the electroformed optical fiber 5
A method of providing an insulating layer 8 against electricity or heat by a method of directly adhering a resin coating layer to the resin or a method of providing a heat-resistant fiber woven layer with a gap therebetween may be adopted. When the resin coating layer is provided in close contact, a heat-resistant, flame-retardant, non-combustible or heat-insulating resin is preferable, and it is particularly preferable to use a foamed resin.

When the heat-resistant and high-strength optical fiber manufactured in this manner is used, FIG. 10 shows an example thereof, but the electroformed optical fiber 5 is inserted into the hole of the ferrule 8 press-fitted into the flange.
After being inserted, the metal tube 6 having the gap 7 may be used in a state where the metal tube 6 is adhered and fixed with an epoxy adhesive or the like. Further, according to the method of the present invention, the electroformed optical fiber and the electroformed portion on the outside thereof are used. Since the concentricity is extremely good and the thickness can be accurately controlled, it is possible to easily connect a connector with a normal ferrule without removing the electroformed portion.

[0023]

According to the method of the present invention, one or a plurality of electroformed metal layers are directly deposited on a ceramic optical fiber elemental wire or an optical fiber core wire to improve the strength against breakage. However, at that time, if necessary, a relatively soft material is used for the metal that is deposited, or if the thickness of the metal is not made too thick, a means to relieve the tightening stress at the time of temperature drop is adopted, and It completely prevents the occurrence of fatal defects such as the breaking of the optical fiber, improves the uniformity of the thickness and the accuracy of the thickness of the electroformed metal by adopting rotary electroforming, and the electroformed part and the optical fiber part. Since the concentricity of the electroformed optical fiber can be improved, it is possible to insert the electroformed optical fiber in the subsequent process into the ferrule as it is and connect it to the connector. , A metal or resin tube with a slightly thick hole is provided with a sufficient space for accommodating the crushing phenomenon of the metal tube that occurs when bending, and by accommodating it, impact force, bending, pulling, etc. It is possible to reliably prevent breakage of the optical fiber when a large force is applied, and
When electroforming directly on the optical fiber core wire, it is possible to reduce the loss of light when bent greatly, and because it has good heat resistance, it can be used indoors or in automobiles. It has a great effect that it becomes possible.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view and a side view showing a general structure of an optical fiber.

FIG. 2 is a diagram showing a state when light is transmitted through the core 1 of the optical fiber.

FIG. 3 is a plan view showing a schematic configuration when a long optical fiber is directly sputtered by a facing target sputtering method according to the present invention.

FIG. 4 is an enlarged cross-sectional view showing a state in which a conducting layer 3 and an electroformed metal layer 4 are formed on the surface of an optical fiber element wire or core wire according to the present invention.

FIG. 5 is a side view showing an example of an optical fiber continuous electroforming apparatus according to the present invention.

FIG. 6 is an enlarged side cross-sectional view showing a state in which the electroformed optical fiber 5 according to the present invention is used while being housed in a metal tube 6 with a gap 7 provided therebetween.

FIG. 7 is an enlarged side view showing a state in which an insulating layer 8 is formed on the outer side of the metal tube 6 when the electroformed optical fiber 5 according to the present invention is used while being housed in the metal tube 6 with a gap 7 therebetween. FIG.

FIG. 8 is an enlarged side cross-sectional view showing a state in which the electroformed optical fiber 5 according to the present invention is used while being housed in a resin pipe 11 with a gap 7 provided therebetween.

FIG. 9 is an enlarged side sectional view showing a state in which an insulating layer 8 is directly formed on the electroformed optical fiber 5 according to the present invention.

FIG. 10 is an enlarged side cross-sectional view showing a state in which the electroformed optical fiber 5 is inserted into the hole of the ferrule 13 according to the present invention, and then the metal tube 6 and the ferrule 13 are bonded and fixed together with an epoxy adhesive or the like.

[Explanation of symbols]

1 core part 2 clad part 3 current-carrying layer 4 electroformed metal layer 5 electroformed optical fiber 6 metal tube 7 gap 8 insulating layer 9 optical fiber 10 electroforming tank 11 resin tube 12 belt 13 ferrule 25 optical fiber receiving pulley 26 plus electrode spring Terminal 27 Negative electrode spring terminal 28 Positive electrode rotation motor 29 Electroforming liquid 30 Structure 31 Metal anode 32 Filter pump 33 Hole 41 Sputtering tank 42 Opposed target 43 Rotating drum

Claims (10)

[Claims] 1. In a ceramic optical fiber such as silica glass or multi-component glass, a metal current-carrying layer 3 is formed on the optical fiber elemental wire or the optical fiber core wire, and the upper layer is electroformed by electroforming. In the electroformed optical fiber 5 having the metal layer 4 formed thereon, a metal of a relatively soft material is formed in the electroformed metal layer 4 with a uniform and accurately controlled thin thickness to be used. , Structure of high-strength optical fiber and manufacturing method thereof. 2. The heat-resistant and high-strength material according to claim 1, wherein the electroformed metal layer 4 is made of nickel, copper, tin, lead or the like and has an Vickers hardness of about 20 to 350. Optical fiber structure and its manufacturing method. 3. The electroformed metal layer 4 has a thickness of 0.01 mm to 0.4 mm.
The structure of a heat-resistant and high-strength optical fiber according to claim 1 or 2, and a method for manufacturing the same, wherein an electroformed metal having a uniform thickness is formed. 4. In a ceramic optical fiber such as silica glass or multi-component glass, a metal current-carrying layer 3 is formed on the optical fiber elemental wire or the optical fiber core wire, and the upper layer is electroformed by electroforming. In the electroformed optical fiber 5 on which the metal layer 4 is formed, the electroformed metal layer 4 is formed with a uniform and accurately controlled thickness, and then the electroformed optical fiber 5 is provided with a gap 7 to form a metal tube 6 or a resin. A structure of a heat-resistant and high-strength optical fiber and a method for manufacturing the same, which is configured to be used by being housed in a tube such as the tube 11. 5. A heat-resistant and high-strength optical fiber structure according to claim 4, and a method of manufacturing the same, wherein an insulating layer 8 against electricity and heat is formed on the outside of the metal tube 6. 6. In a ceramic optical fiber such as silica glass or multi-component glass, a metal current-carrying layer 3 is formed on the optical fiber elemental wire or the optical fiber core wire, and an electroforming method is applied to the upper layer thereof by electroforming. In the electroformed optical fiber 5 on which the metal layer 4 is formed, the electroformed metal layer 4 is formed with a uniform and accurately controlled thickness, and then an insulating layer 8 for electricity and heat is provided outside the electroformed optical fiber 5. A structure of a heat-resistant and high-strength optical fiber, characterized in that 7. The method according to claim 5, wherein a method of forming an adhesive resin coating layer on the insulating layer 8 against electricity or heat, or a method of providing an insulating fiber woven layer with a gap therebetween is adopted. Heat-resistant and high-strength optical fiber structure and its manufacturing method. 8. A method of forming an adhesion resin coating layer on an insulating layer 8 against electricity and heat, wherein a foamed resin layer having heat resistance, flame retardance or noncombustibility is formed. Heat-resistant and high-strength optical fiber structure and its manufacturing method. 9. A method for forming a metal current-carrying layer 3 on an optical fiber element wire or an optical fiber core wire, wherein a long-winding optical fiber is introduced into a sputtering tank by a double-sided simultaneous film formation method by sputtering a facing target. And adopting a method of continuously sputtering a long optical fiber.
8. A structure of a heat-resistant and high-strength optical fiber according to 8, and a manufacturing method thereof. 10. An electroformed optical fiber 5 whose thickness is accurately controlled.
The heat-resistant glass according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9 which is manufactured by directly inserting into the hole of the ferrule 8 in the state of the electroformed optical fiber 5. , High-strength optical fiber structure and manufacturing method thereof.