JPH02309305A - Heating method, exothermic resistor and heating furnace for fusion-joining of optical fibers - Google Patents

Abstract

PURPOSE:To obtain the method which allows many times of fusion joining operations by using ceramics which consists essentially of zirconium oxide and is added with a prescribed oxide in order to stabilize the zirconium oxide and to lower the resistance thereof. CONSTITUTION:A heating furnace 10 is constituted by forming an exothermic body part of an exothermic resistor 12 consisting of the ceramics and forming a heating chamber 14 of this exothermic resistor 12 as an inner space communicating with an outside space. The exothermic resistor 12 is energized to generate heat by a pair of electrodes 16 from an external power source (not shown). Optical fibers 18a, 18b to be joined are fusion- joined at joining end faces 18c of both fibers by heating the exothermic resistor 12 to >=1600 deg.C surface temp. This exothermic resistor 12 is constituted of the ceramics essentially consisting of the zirconium oxide (ZrO2) and is formed by adding one or two kinds of the oxides, such as Y2O3, CaO and MgO thereto in order to stabilize the ceramics and to lower the resistance thereof. The exothermic resistor is thereby provided with the sufficient heat resistance even when subjected to a temp. change from room temp. to >=1600 deg.C and up to about 2000 deg.C. The heating furnace 10 which is stable at a high temp., has a long life and is used for fusion-joining of the optical fibers 18a, 18b is obtd.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a heating method for melting and joining the end faces of two optical fibers, a heating resistor for performing this heating, and a heating resistor for performing this heating. It is placed between two heating furnaces.

(Prior Art) As is well known in the art, optical fibers are used as an important means of transmitting optical signals. As is well known, such optical fibers usually consist of a core with a high refractive index and a rad with a low refractive index around it. The cladding glass has a glass composition containing, for example, germania (GeO□) as a dopant, and the clad glass has a glass composition containing, for example, boron oxide (B203) or fluorine (F)1 as a dopant. Therefore, the core begins to melt at temperatures above about 1600'C.

When optical fibers are used as optical transmission means, usually multiple optical fibers are connected sequentially using optical connectors to form a signal path, or multiple optical fibers are connected sequentially to their end faces. In this process, the optical fibers were permanently bonded to form a signal path as a single long optical fiber.

As is well known, the methods of joining the end faces of optical fibers as reviewed above include: 1) using a V-groove or sleeve to butt one end of the fibers together and fixing them with adhesive; 2) joining one end of the fiber using a V-groove, etc. There is a method of aligning the two and heat welding (also referred to as heat fusion) using arc discharge, carbon dioxide laser, or the like. The heat welding method using arc discharge is currently mainstream because the device is small and the melting conditions can be easily controlled.

(Problem to be solved by the invention) However, in such a heat welding method using arc discharge, a spark is applied from the outside to the welded end of the bare optical fiber to be joined, so there is no chance of sparks entering the molten joint. Due to the gas generated due to this! There was a risk that objects could get in there and make the joints brittle. In addition, since heating is performed directly by sparks, it is not possible to accurately control the heating temperature of the fiber, and it is difficult to control the fiber heating temperature.
Since it will not melt unless it is heated above C, there is a problem in that it takes at least one hour to heat to that temperature.

In addition, in order to more accurately control the heating temperature and shorten the heating time, heaters have been constructed of suitable materials and are being tried or actually used to fuse optical fibers together.
None of these heaters have sufficient heat resistance to withstand temperatures as high as 1,600 degrees Celsius, and most of these heaters are rendered unusable due to breakage after the first bonding, mainly due to changes in density due to temperature changes. Therefore, there was a problem that usage efficiency was extremely low.

Therefore, the inventor of this application conducted various studies on heaters and materials with the aim of forming a heater that can eliminate these problems, and found that the minimum conditions that a heater material should have are at least 51800'C or 2000"
They came to the conclusion that the material has sufficient heat resistance fl: even at high temperatures such as C, has a long life and low vapor pressure, and that the electrical resistance of the material decreases as the temperature increases.

Therefore, when we investigated whether there were any oxides among heat-resistant ceramics that met these conditions, we found that Zr0
It was found that there is a z (stabilized) bi-stabilized zirconia. Figure 2 is an electrical resistance characteristic curve diagram of stabilized zirconia, in which the horizontal axis represents temperature (X100°C) and the vertical axis represents electrical resistance in terms of specific resistance p (Ωcm). This characteristic curve is understood to have been obtained by heating stabilized zirconia and measuring its surface temperature and electrical resistance at that time.
When the surface temperature is around 400°C, ρ is around 105Ωcm, at 800°C it is around 10'Ωcm, and at 1600°C, ρ is around 10'Ωcm.
Approximately 101ΩCm at 2000'C, roughly 1000Ω at 2000'C
It can be seen that the specific resistance ρ decreases significantly as the temperature increases, as shown in the figure.

Furthermore, as is well known, the vapor pressure of zirconia (ZrOh) is extremely low at about 106' mmHg at about 2000°C. In Figure 3, the vapor pressure of this zirconia is plotted on the horizontal axis, and the temperature (X
100°C) and the vapor pressure p (mmHc+) is plotted on the vertical axis.

In addition, Cab, M2O, and La are added to zirconia (ZrOz).
Stabilized zirconia obtained by adding either 2O3, Y2O3, etc. is relatively stable against temperature changes from room temperature to around 2000°C, and therefore has excellent heat resistance with little risk of destruction. It is known that
In fact, when we conducted a destructive experiment by heating, we found that the temperature was 2000℃.
It was confirmed that the material had excellent heat resistance even at different temperatures.

Therefore, the invention of this application was made by focusing on the above-mentioned special ratios of stabilized zirconia.

Accordingly, a first object of the present invention is to provide a heating method for melting and joining optical fibers, which can reliably melt and join optical fibers in a short period of time.

The second object of this invention is to create a heat-generating resistor that is small in size, has heat resistance even at high temperatures of about 2000'C, and generates more heat as the temperature increases even at the same voltage, and which becomes an impurity for optical fibers. It's about offering your body.

Roughly speaking, the third object of the present invention is to use such a heating resistor to withstand at least 100 uses, and in some cases to be able to raise the temperature to about 1600°C in a short period of just a few minutes. Our purpose is to provide heating furnaces.

(Means for Solving the Problem) In order to achieve this object, according to the heating method for fusion bonding of optical fibers of the present invention, zirconium oxide (Z r 02 ) as a main component and stabilization of this zirconium oxide. A heating resistor made of ceramic inx containing a heat-generating resistor and an oxide for lowering the resistance is preheated externally to raise the temperature of the heat-generating resistor and reduce its resistance value, and then the heat-generating resistor is Apply voltage to cause current to flow and generate heat.

Heat is generated on the surface of the heating resistor to a temperature of at least approximately 160° C., and the heat generated heats each connecting end of the optical fiber, thereby melting and bonding the joining end surfaces to each other.

In this case, the preheating is preferably from 800°C to 140°C.
It may be carried out to any suitable temperature between 0°C.

Further, in the embodiments of the present invention, preheating may be performed by direct heating from an external heat source, or by supplying electricity to a preheating resistor provided in advance on the outside of the heat generating resistor and using heat generated by the preheating resistor.

In general, it is preferable to energize the heating resistor using an AC power source.

In general, the heating resistor for fusion bonding of optical fibers of the present invention is mainly composed of zirconium oxide (ZrO□).
It is composed of ceramics mainly containing zirconium oxide and an oxide for stabilizing the zirconium oxide and lowering its resistance.

In carrying out this invention, the oxides preferably include yttrium oxide (Y2O3), calcium oxide (Ca
It is preferable to use one or more oxides selected from the group of O), magnesium oxide (M2C), and rare earth oxides.

Further, in a preferred embodiment of the present invention, this ceramic
It is preferable that the amount of oxide contained in the oxide is 20 mol% or less.

Furthermore, the heating furnace for melting and bonding optical fibers of the present invention uses ceramics containing zirconium oxide (CZ, r○2) as a main component and an oxide for stabilizing and lowering the resistance of this zirconium oxide. a heating resistor configured as such, and a penetrating inner space surrounded by the heating resistor, and capable of accommodating a portion of each of at least a pair of optical fibers before and after fusion bonding, in a freely insertable and removable manner. The heating chamber has a structure including a heating chamber, and a pair of electrodes each connected to an external power source and provided on each heating resistor for energizing the heating resistor.

In this case, preferably the inner space constituting the heating chamber is
It is preferable that a portion of each of the pair of optical fibers before and after fusion bonding be communicated with the outer space of the heating resistor through a gap for insertion into and removal from the inner space.

Furthermore, in carrying out the present invention, the thickness of the heating resistor is made such that the thickness of the portion surrounding the central portion extending in the penetrating direction of the inner space is thinner than the thickness of the portion surrounding both the entrance and exit sides of the inner space. It is better to have a structure.

In general, it is preferable that electrodes be provided on the outer periphery of each portion of the heating resistor surrounding both the entrance and exit sides along the penetrating direction of the inner space.

In general, preferably, these pair of electrodes are formed from a platinum group element.

Further, according to a preferred embodiment of the present invention, a preheating resistor can be provided over a part of the outer periphery of the heating resistor to bridge a pair of electrodes.

In general, it is preferable that this preheating resistor is made of a noble metal alloy material.

Preferably, the precious metal alloy material is platinum (Pt).
and one or more noble metals selected from the group of iridium (Ir), rhodium (Ro), and rhodium (Japanese U).

In carrying out the present invention, the noble metal alloy material is preferably a material containing platinum (pH 80-70M!!!%) and iridium (Ir) 820-30% by weight.

In general, it is preferable that the preheating resistor has a mesh, grid, or car shape.

(Function) The heating resistor for fusion bonding of the optical fiber of the present invention described above is composed of ceramics of zirconium oxide (ZrO2) and an oxide for stabilizing the zirconium oxide and lowering its resistance. Even when the temperature changes from 2000℃ to around 2000℃, it melts #! It has sufficient heat resistance even if it is exposed to such high temperatures during the bonding process, and there is no risk of it breaking due to changes such as 2 degrees.
In addition, the electrical resistance of this heating resistor decreases as the temperature increases from room temperature, so even if the voltage is held constant, the amount of heat generated increases, so thermal efficiency is extremely high.

Further, after the end faces of a pair of optical fibers to be joined are held abutting against each other in a heating chamber of a heating furnace constituted by such a heating resistor, this heating furnace is preheated from an appropriate external heat source. This preheating increases the temperature of the heating resistor in a short time and lowers its electrical resistance. Thereafter, by applying electricity to the heating resistor from the outside through the electrodes, it generates heat in a short period of at least 3 to 4 minutes at a high temperature of 1,600°C or more, which is necessary for fusion joining of optical fibers, and substantially maintains the optical fibers at that temperature. heat up. During this high-temperature heating, in which the fused optical fibers are taken out of the heating chamber and out of the heating furnace, impurities caused by gas that would occur in the case of sparks are not generated, so there is no risk of impurities getting into the fused joint. Therefore, there is no risk of deterioration of the joint due to impurity contamination.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following explanation is merely a preferred example, and therefore,
The present invention is not limited only to these embodiments, and the figures schematically show the shape, size, arrangement relationship, etc. of each component to an extent that the present invention can be understood. Not too harsh.

In the following explanation, the heating method and the heating element will be explained together with the explanation of the embodiment of the heating furnace.

FIG. 1(A) is a perspective view showing a preferred embodiment of a heating furnace for melting and bonding optical fibers according to the present invention, and FIG. It is a sectional view taken along a line.

This heating furnace 10 has a heat generating main body (also referred to as a heating main body) composed of a heat generating resistor 12 made of ceramic, and this heat generating resistor 12 defines a heating chamber 14 as an inner space communicating with an external space. to form. Then, in order to generate heat in this heating resistor 12, electricity is applied to it, and for this purpose, a pair of electrodes 16 are connected to an external power source.
is provided in the heating resistor 12.

These points will be described in detail below with reference to FIGS. 1(A) and 1(B). Although the optical fibers are not shown in FIG. 1A, the optical fibers are indicated by imaginary lines 18a and 18b in FIG.

Further, the end faces where both optical fibers are joined are commonly shown at 18c ().

Ceraminx, which makes up the heating resistor, has zirconium oxide (ZrO2) as its main component, and is a material called stabilized zirconia, which is made by adding an oxide to this zirconium oxide as an additive to stabilize it and lower its resistance. Consisting of

This oxide is usually yttrium oxide (Y2O
3), calcium oxide (CaO), magnesium oxide (
M 90) and one or more oxides selected from the group of rare earth oxides 6-As an example, the heating resistor is composed of zirconium oxide and 20 mol% or less of the oxide. is preferable. The reason why the oxide content is 20 mol % or less is to ensure heat resistance at high temperatures of 800° C. or higher, long life, and low resistance. It can be assumed that stabilized zirconia obtained by adding any of the above-mentioned oxides shows a relationship between temperature and electrical resistance almost similar to that shown in FIG. 2.

For example, when a heating resistor is energized to generate heat,
At a heating temperature of 00℃, the specific resistance ρ is a little less than 10'Ωcm,
Approximately 102~ with exothermic temperature of 1400℃~16oO℃
The resistance value (Ω) is approximately 101 Ωcm, and the resistance value (Ω) is approximately 101 Ωcm at a heat generation temperature of approximately 2000'C.As described above, it can be understood that the resistance value (Ω) decreases significantly as the temperature increases.

Furthermore, as already mentioned, the vapor pressure of such stabilized zirconia at high temperatures is extremely low, so when heated at high temperatures, gases are generated that may enter the fused joints of the optical fibers 18a and 18b as impurities from the ceramics. can be virtually avoided. Therefore, there is no risk that the joint will deteriorate and break.

Further, such stabilized zirconia is stable in the dark for a long time even at a high temperature of 2000° C. Therefore, a heating furnace formed of this heating resistor has a long life and can withstand repeated use more than 100 times.

A heating chamber 14 surrounded by such a heating resistor 12 contains optical fibers 18a, 18b which are melted and bonded to each other! a Heating resistor 1 for heating the inserted and fixed fiber
2, and is provided so as to penetrate through this heating resistor 12. Of course, the narrow groove (or also referred to as gap, void, slit, or slot) 2 for insertion and removal of the optical fibers 18a and 18b before and after joining.
0 and a structure in which the heating chamber 14 and the outer space of the heating furnace 10 are communicated with each other. Optical fiber 18a of this heating chamber 14.

The cross-sectional shape in a plane perpendicular to the direction in which 18b extends is:
Any shape is sufficient as long as it can secure a space in which at least one pair of optical fibers can be fixed. Therefore, the shape may be circular, for example,
It can be any suitable shape depending on the design such as an ellipse, a rectangle, a triangle, or a triangle thereof. In addition, the heating chamber 14 may be formed as a space where the optical fibers 18a, 18b1yj can be fixed with the inner wall of the heating resistor 12 to prevent play, or may be formed as a space where the optical fibers 18a, 18b1yj can be fixed with the inner wall of the heating resistor 12, or the ends of the optical fibers to be joined may be fixed. After fixing the part with a so-called split sleeve (sleeve with slit), a space may be formed so that the split sleeve can be fixed in the heating chamber 14 with the split sleeve attached, or alternatively, a plurality of pairs of optical fibers may be attached. It is possible to form a space in which a pair of optical fibers 18a and 18b can be housed and fixed in parallel.The type of heating chamber structure to be used is merely a matter of design. A split sleeve 22 schematically showing a state in which the end faces are butted and fixed by the split sleeve 22.
Since it is publicly known, a detailed explanation thereof will be omitted, but
In this case, like the heating furnace, if it is made of stabilized zirconia, it will have excellent heat resistance at high temperatures and will also have extremely good heat transfer efficiency from the heating furnace 24. In addition, FIG. 5 shows an example of the heating chamber 26 of the heating furnace 24 for accommodating and melting a plurality of pairs of optical fibers at the same time.
The figure shows one end surface of the heating furnace 24 as seen from the direction along the penetrating direction of the heating chamber 26. 28 is a position for positioning the optical fiber, 30 is a heating resistor, 32 is a heating chamber 26 (a gap for inserting and removing the optical fiber thereto, and 34 is an electrode). It is preferable to fix the optical fiber with a split sleeve like this, install the optical fiber, and heat and melt it.

The explanation will be given again by returning to FIGS. 1(A) and (8). The outer shape of the heat generating body, which is the heat generating resistor 12, may have any shape as long as it has a structure that allows at least one pair of optical fibers to be connected or joined to each other to be inserted into and removed from the heating chamber 14. In addition to this,
Preferably, the outer shape is simple and easy to handle, and can be stably fixed especially during the melting operation.The heating chamber 14 penetrates through the outer shape, for example, square, spherical, cylindrical, etc. or any other suitable block shape. ! Alternatively, it may be configured to be held and fixed by any suitable means (not shown) that can withstand high temperatures.

In addition, in order to increase the heating efficiency of the heating furnace 10, the heating chamber 14
It is preferable that the wall thickness of the wall portion of the heat generating body portion 12 surrounding the center side portion along the penetration direction of the inner space is made thinner than the wall thickness of both end portions. When considering a cross section in a plane perpendicular to the penetration direction with the chamber 14 as the center, the wall thickness of the left and right walls should be thinner near the center in the penetration direction with the gap 18 located on the upper side. Alternatively, the entire circumference (angle range of 360°) of the heating chamber 14 may be made thin.

Next, the electrode 16 will be explained.

A pair of electrodes 16 for energizing the heating resistor 12 are provided on the outer periphery of both ends of the heating resistor 12, and these electrodes are connected to a required external AC power source, such as a commercial power source (not shown) such as 240V. Configure it so that it can be connected.

This electrode 16 is preferably provided on the outer periphery of a wall surrounding the entrance/exit side along the penetration direction of the heating chamber (inner space) 14 of the heating resistor 12, as shown in FIG. 1(A), for example. . The heating furnace 10 is normally heated to 1600°C or higher, for example,
Since the electrodes 16 are used at a high temperature of just over 2000° C., the pair of electrodes 16 are preferably made of a platinum group element in order to prevent the electrode characteristics from deteriorating even at such high temperatures. These electrodes 16 can be applied to the heating resistor 12 using conventional thick film deposition techniques such as sputtering or powder coating.

In the heating furnace 10 described above, if an external power source is connected to the electrode 16 and the heating resistor 12 is made to generate heat, the internal temperature will rise in accordance with the heat generated in the heating chamber 14.

As the heat generation temperature rises, as already explained, the resistance value of the heat generation resistor 12 decreases, so the current increases,
The amount of heat generated also increases, and therefore the temperature of the heating chamber 14 also rises roughly. In practice, the resistance value of the heating resistor 12 is set to approximately 1600".
C, the maximum resistance is about 10 OKΩ, but preferably about 1
At 600°C, we want to generate about 10W of heat at a voltage of 240V, so it is best to design the resistance value to be 5 to 6Ω at this temperature.

By the way, it takes time to raise the temperature of the heating resistor 12 from room temperature to about 1600°C, which is not preferable for melting and bonding work. The temperature of the heating resistor 12 can be raised more quickly by effectively utilizing an external heat source until the internal temperature reaches an appropriate temperature. Therefore, for example, the heating resistor 12 may be preheated externally using a burner or the like. In this case, the gas generated by the burner is directly fused into the optical fiber by being shielded from the heating furnace 10T:J. There is no risk of impurities getting into this joint.

Instead of using such a burner or the like, in the present invention, a preheating resistor (also referred to as a preliminary resistor) as shown in FIG. 6 can be used. This will be explained. FIG. 6 is a perspective view showing a state in which the preheating resistor 30 is attached to the heating furnace 10 shown in FIG. 1(C), and shows the same components as those shown in FIG. 1(A). The explanation thereof will be omitted.

This preheating resistor 40 is provided on the outer periphery of the heating resistor 12 except for the narrow groove 20 for inserting and removing the optical fiber. This preliminary electrode 40 is provided so as to bridge the pair of electrodes 16, and is brought into ohmic contact with these electrodes 16. This preliminary resistor 40 is the resistance axis! ! A mesh-like resistor (configuration example shown in Fig. 6), a grid-like resistor with parallel resistor wires, a gauze-like resistor with resistor wires, or any other resistor. It can be formed in the form of

Preferably, the resistor material of the preliminary resistor 40 is made of one or more noble metal alloy materials selected from platinum (Pt), iridium (Ir), rhodium (Ro), and ruhidium (ru). This is because these noble metal alloy materials are stable even at temperatures of 1600° C. or higher. For design reasons such as high melting point, high resistance value, and ease of processing, this alloy material preferably contains 80 to 70% by weight of platinum and 820 to 30% by weight of iridium.
In addition, such noble metal alloy materials have a long service life even when used at high temperatures for long periods of time.

When such a preheating resistor 4o is provided in ohmic contact with the electrode 16 and connected to an external power source, since the resistance value of the heating resistor 12 is large at room temperature, the preheating resistor 40 is connected to the preheating resistor 40. Most of the current flows and generates heat, heating the heating resistor 12. As the heating temperature increases, the current flowing through the heating resistor 12 also increases. When the heating temperature is about 1 to 800 degrees Celsius, approximately the same amount of current flows through both paper antibodies 12 and 40. At higher temperatures, more current flows to the heating resistor 12, and when the heating temperature is about 1400 degrees Celsius, almost the same amount of current flows through the heating resistor 12. is made to flow through the heating resistor 12.

In this way, by using preheating by an external heat source, it is possible to increase the heat generation temperature of the heating furnace 10, and hence the heating temperature, to about 1800° C. within a short time of 3 to 4 minutes.

It is clear that the invention is not limited only to the embodiments described above, but can be subjected to many variations and modifications.

In the embodiments described above, no mention is made of the outer diameter of the heating furnace, but the dimensions can be set in various ways depending on the design, and a smaller size is more convenient for use.

Furthermore, it is also a design problem how to set the respective resistance values of the heating resistor and the preheating resistor of the heating furnace.

Furthermore, the shape of the inner space n constituting the heating chamber can be arbitrarily determined according to the design.

(Effects of the Invention) According to the above-described heating furnace for melting and joining optical fibers of the present invention, the heating resistor constituting the furnace heats up from room temperature to 1.
It has sufficient heat resistance even when subjected to temperature changes from 600°C to about 2000°C, and even when exposed to high temperatures for long periods of time, is stable at high temperatures, has a long life, and can therefore be melted and bonded at least 100 times or more. Sufficiently durable for work use.

In addition, since the heating resistor of this heating furnace is made of stabilized zirconia, when electricity is applied to the heating resistor to generate heat and raise the temperature, the electrical resistance value decreases.
When changing the heat generation temperature from room temperature to a high temperature of 1600℃ or higher, the current increases as the heat generation temperature increases while keeping the externally applied voltage constant, and as a result, the heat generation amount increases, and therefore the heat generation temperature also increases. . Therefore, the thermal efficiency is better than that of the conventional method, and since the electrical resistance with respect to the heat generation temperature is known, the heating temperature can be accurately controlled by adjusting the voltage application time.

Furthermore, since the method uses electrical heating in a heating furnace, there is no risk of impurities getting into the melt-joined end faces of the optical fibers to be joined, so there is almost no risk of breakage at the joint.

The heat generated by the electric heating furnace itself and up to a certain temperature,
By heating this heating furnace using an external auxiliary heat source, it is possible to raise the temperature to approximately 1600"C, which is required for fusion bonding, in a fraction of the time, so the time required for fusion bonding work is reduced. It can be made shorter than before.

[Brief explanation of drawings]

FIG. 1(A) is a perspective view schematically showing an example of the structure of a heating furnace used for explaining the present invention, and FIG. 1(8) is a perspective view taken along the line X-X in FIG. 1(A). FIG. 2 is a temperature-electrical resistance (specific resistance) characteristic curve diagram of stabilized zirconia, which is used to explain the present invention, and FIG. 3 is a vapor pressure characteristic of zirconia, which is used to explain this invention. A curve diagram; FIG. 4 is an explanatory diagram for explaining an example in which the joined end surfaces of optical fibers are fixed with a split sleeve; FIG. 5 is a diagram for explaining another embodiment of the present invention; FIG. 2 is a perspective view for explaining another embodiment of the present invention using a preheating resistor. 10.24... Heating furnace, 12.3o... Heating resistor 14.26... Heating chamber (inner space) 16.34... Electrode, 20.32... Thin groove 22
... Split sleeve, 28... Optical fiber installation f
f1ffi, 40...Resistor for preheating. Patent Applicant: Adamacid Industries Co., Ltd. Jump-view diagrams of examples 18a and 18b Optical fibers 18c Cross-sectional views of end face embodiments of optical fibers Figure 1 Temperature (xlOO℃) Electrical resistance of stabilized zirconia Figure 2 Temperature (cutting OO℃) ) Vapor pressure of zirconia Fig. 3 8a Explanatory diagram of split sleeve Fig. 4 Explanatory diagram of other English examples

Claims (19)

[Claims] (1) After preheating a ceramic heating resistor containing zirconium oxide (ZrO_2) as the main component and an oxide for stabilizing and lowering the resistance of the zirconium oxide from the outside, the heating resistor is heated. 1. A heating method for melting and joining optical fibers, which comprises generating heat at a surface temperature of at least approximately 1600° C. or higher by applying electricity, and melting and joining optical fibers using the heat generation. (2) The heating method according to claim 1, wherein the preheating is performed to an arbitrary temperature of 800°C to 1400°C. (3) The heating method according to claim 1 or 2, characterized in that the preheating is performed by applying electricity to a preliminary heating resistor provided outside the heating resistor. (4) The heating method according to claim 1, 2 or 3, wherein the heating resistor is energized using an AC power source. (5) A heating resistor for fusion bonding of optical fibers, characterized by being made of ceramics containing zirconium oxide (ZrO_2) as a main component and an oxide for stabilizing the zirconium oxide and lowering its resistance. (6) Oxides such as yttrium oxide (Y_2O_3), calcium oxide (CaO), magnesium oxide (MgO)
6. The heating resistor for fusion bonding of optical fibers according to claim 5, characterized in that the heating resistor is made of one or more oxides selected from the group of rare earth oxides. (7) The heating resistor for fusion bonding of optical fibers according to claim 5 or 6, characterized in that it contains zirconium oxide and 20 mol% or less of an oxide. (8) A ceramic heating resistor containing zirconium oxide (ZrO_2) as a main component and an oxide for stabilizing and lowering the resistance of the zirconium oxide, and a penetrating inner space surrounded by the heating resistor. a heating chamber configured to removably accommodate a portion of each of the at least one pair of optical fibers before and after fusion bonding; and a heating chamber that is connected to an external power source to energize the heating resistor. 1. A heating furnace for melting and bonding optical fibers, comprising a pair of electrodes respectively provided on the heating resistor. (9) The inner space constituting the heating chamber connects to the outer space of the heat generating resistor through a gap for inserting and removing a portion of the pair of optical fibers before and after melt bonding into the inner space. 9. The heating furnace for melting and joining optical fibers according to claim 8, wherein the heating furnace is in communication with each other. (10) The heating resistor is characterized in that the thickness of the portion surrounding the central portion along the penetrating direction of the inner space is thinner than the thickness of the portion surrounding both the entrance and exit sides of the inner space. A heating furnace for melting and joining optical fibers according to claim 8 or 9. (11) The heating resistor according to any one of claims 8 to 10, characterized in that electrodes are provided on the outer periphery of each portion surrounding both the entrance and exit sides along the penetrating direction of the inner space. Heating furnace for melting and joining optical fibers. (12) The heating furnace for melt-joining tip fibers according to any one of claims 8 to 11, wherein the pair of electrodes is made of a platinum group element. (13) The optical fiber fusion bonding method according to any one of claims 8 to 12, further comprising a preheating resistor bridging the pair of electrodes over a part of the outer periphery of the heating resistor. Furnace for. (14) The heating furnace for melting and joining optical fibers according to claim 13, wherein the preheating resistor is made of a noble metal alloy material. (15) Precious metal alloy materials include platinum (Pt), iridium (Ir), rhodium (Ro), and rubidium (Ru).
15. The heating furnace for melting and joining optical fibers according to claim 14, characterized in that one or more noble metals selected from the group of: (16) Precious metal alloy material contains platinum (Pt) at 80 to 70%
15. The heating furnace for melting and joining optical fibers according to claim 14, wherein the heating furnace contains 20 to 30% by weight of iridium (Ir). (17) Claim 1 characterized in that the preheating resistor is a mesh-like, grid-like, or gauze-like resistor.
17. A heating furnace for melting and joining optical fibers according to any one of 3 to 16. (18) Yttrium oxide (Y_
2O_3), calcium oxide (CaO), magnesium oxide (MgO), and one or more oxides selected from the group of rare earth oxides. Furnace for. (19) The heating resistor contains zirconium oxide and 20 mol%
The heating furnace for melting and joining optical fibers according to claim 8, characterized in that it contains the following oxides.