JPS61124904A - Optical waveguide device for light power transmission - Google Patents

Abstract

PURPOSE:To maintain an optical fiber end surface in an excellent state without any wet of liquid by composing an optical fiber holding means of a magnetic circuit and magnetic liquid and using this optical fiber holding means at both end parts, and arranging cooling liquid between them and cooling the optical fiber. CONSTITUTION:The magnetic liquid 13 is confined in an intense magnetic filed established by magnetic poles 12 and converged on the tip part of the magnetic pole, but the magnetic field is not present at the center part of four magnetic poles, so a cavity where there is no magnetic liquid is formed at the center part of the magnetic poles unless there is another body at the magnetic pole center part. End parts 14 of a flexible tube are connected to the end surface of the ring-shaped magnet 11 and magnetic poles 12 of an optical fiber support 7, and the size of the end part opening 14a is larger than the diameter of the optical fiber and smaller than the diameter of the outer periphery of the magnetic liquid 13. The magnetic liquid 13 constitutes part of the support for the optical fiber and seals the oil or cooling liquid in the flexible tube.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a light guide device for transmitting optical power, which transmits large optical power through an optical fiber.

2. Description of the Related Art In a conventional power transmission light guide device, as shown in FIG. 6, air, etc. A method of cooling by flowing gas is being considered. Although this type of gas cooling is effective because it is easy to use and has a moderate cooling effect, as the transmitted power increases, self-heating due to light absorption within the optical fiber also increases, and the gas However, sufficient cooling cannot be obtained by cooling. In addition, in the method of applying the heat pipe idea shown in Fig. 6 to the surroundings of optical fibers (Japanese Unexamined Patent Publication No. 66-41
Publication No. 04) Due to the structure, the vicinity of both ends of the optical fiber 3 sa,
3b and the end walls 4a, 4b of the pipe 4, the heat pipe interior 5 cannot be hermetically sealed to a highly reduced pressure state, and the heat pipe cannot exhibit its full effect. Furthermore, there is a high possibility that the working fluid may leak from the gap and the end face of the optical fiber may not be trimmed.

Problems to be Solved by the Invention When trying to transmit a large amount of original energy using an optical fiber, the amount of optical power transmitted cannot be increased very much due to the temperature rise due to self-heating caused by absorption of optical energy. There is.

Means for Solving the Problem When attempting to cool an optical fiber with a liquid, it is essential to create a structure in which the cooling liquid does not leak into the end face of the optical fiber and the end face is not wetted by the cooling liquid. As a method for holding the optical fiber near the end face of this reservoir, an optical fiber holding means is used that does not damage the optical fiber or apply excessive mechanical load, and has a sealing effect against the cooling liquid, using a magnetic circuit and magnetic fluid. The optical fiber is cooled by disposing a cooling liquid between the fiber holding means at both ends and between them.

Function The other parts of the optical fiber except the end face are effectively cooled by the liquid, and the vicinity of the end face is sealed with the cooling liquid by a fiber holding mechanism having a sealing effect, so that the state of one end face of the optical fiber is changed to a liquid state. It can be maintained in good condition without getting wet.

Embodiment FIG. 1 is a sectional view showing an embodiment of the present invention, in which 6 is an optical fiber, 7 is an optical fiber support made of magnetic fluid, 8 is a cooling liquid, and 9 is an optical fiber and a flexible fiber containing the cooling liquid inside. tube.

It has an inlet 10a and an outlet 10b near both ends through which the cooling liquid flows.

Regarding the optical fiber support using magnetic fluid shown in Fig. 1,
explain in detail. FIG. 2 shows an AA cross section of the optical fiber support. 11 is a ring-shaped magnet that is magnetized in the circumferential direction. In the case of the figure, there are four poles, and a magnetic pole 12 is disposed at the position of the magnetic pole, and a magnetic fluid 13 is injected into the center of the magnetic pole 12.

The magnetic fluid 13 is confined by the strong magnetic field formed by the magnetic poles 12 and is concentrated at the tips of the magnetic poles.On the other hand, there is no magnetic field at the centers of the four magnetic poles, so other objects are not present at the centers of the magnetic poles. If it does not exist, a cavity is formed in the center of the magnetic pole where no magnetic fluid exists. This cavity is almost circular, and when an optical fiber that is slightly thicker than its diameter is inserted into this part, the optical fiber is a non-magnetic material, so it does not receive any force from the magnetic field, but the magnetic fluid causes a magnetic pole. It receives a force moving toward the center, that is, the center of the magnetic fluid, and is stabilized at the center in a self-centering manner.

The end portion 14 of the flexible tape is integrally connected to the end surfaces of the ring-shaped magnet 11 and the magnetic pole 12 of the optical fiber support 7, and the dimension of the end opening 14a is larger than the diameter of the optical fiber, and the magnetic fluid 13 The range is selected to be smaller than the diameter of the outer periphery. The magnetic fluid 13 constitutes a part of the optical fiber support as described above, and also has a sealing effect against the oil or cooling liquid inside the flexible tube, and is used to connect the flexible tube 9 and the optical fiber. With the support 7, the optical fiber 6 can be penetrated through the inside while being supported at the center, and the cooling liquid can be completely sealed, so that the cooling required as a light guide for power transmission can be performed without using magnetic fluid. However, it is quite difficult to provide the end of a flexible tube with a cooling liquid sealing effect and a function as an optical fiber support. In the case of power transmission optical fibers that do not have a core φ clad structure but only have a core, a crystalline material is often used, for example, an optical fiber made of KH2-s. In this case, the material is quite soft, and mechanical support can cause damage to the optical fiber. When a scratch occurs, light absorption occurs in that area9, causing heat generation.

Furthermore, even if a mechanical support that does not scratch can be created, it is difficult to provide a sealing effect against the cooling liquid, and in the long run, the cooling liquid may ooze out and wet one end of the optical fiber. Become.

A high-energy laser is incident on or emitted from one end of an optical fiber, or coolant such as oil is generally not a material that transmits laser light well, so when the coolant wets the end, it absorbs the transmitted laser light and the The material of the flexible tube may be resin or metal, but the end portion 14 must be a non-magnetic material.

In addition, if the cooling effect can be obtained without cooling by flowing a cooling liquid, the liquid inlet 10a and the liquid outlet 1ob may be closed and used. Fig. 3 explains another embodiment. FIG. 4 is a sectional view taken along the line CC in FIG. 3. e is an optical fiber, 7 is an optical fiber holder, 14 is a metal tube, 15 is a wick made of thin metal fiber, etc., 1
6 is an evaporative working fluid impregnated into the wick, 17 is a tube end wall made of a non-magnetic material, 1 is a tube end wall opening, 19 is a cooling liquid, 2o is a cooling liquid inlet, and 21 is a cooling liquid outlet. , 22 is an outer cylinder.The structure of the optical fiber holder 7 is the same as that shown in FIG. 2, and the optical fiber 6 is attached to this holder 7.
It is kept soft. The end wall 1a of the tube 14 is integrally connected to the optical fiber holder 7, and the dimensions of the end wall opening 18 are selected to be larger than the diameter of the optical fiber and smaller than the diameter of the outer circumference of the magnetic fluid. As described above, the magnetic fluid supports the optical fiber and has a rail effect, so the heat pipe interior 23 is composed of the optical fiber holder 7 and the tube 14, excluding the vicinity of the end of the optical fiber. A completely sealed state is formed, making it possible to reduce the pressure to a high degree. The wick 15 is composed of an inner wick portion 162 along the circumference of the optical fiber 6, an outer wick portion 151 along the inner wall of the tube 14, and a number of bridge portions 153 connecting the two. Appropriate evaporative working fluid 1 for the wick
6 is impregnated, and the inside of the heat pipe 23 is highly depressurized so that it can evaporate at a lower temperature.0 When the laser light is transmitted through this optical fiber 6,
If there are parts of the optical fiber that absorb light, such as defects, the temperature of that part will rise.

The working fluid in the wink near the temperature rising part evaporates at this temperature, but the heat of vaporization at this time cools the temperature rising part of the optical fiber, suppressing the temperature rise. On the other hand, the evaporated vapor propagates inside the heat pipe as indicated by the arrow 16', reaches the quick portion 151 that dissolves in the inner wall of the tube, becomes liquefied, and penetrates into the wick around the quick portion 151. Since there are a number of bridge parts 163 between the outer wick 151 and the inner wick 162, the working fluid returns to the inner wick 152 due to the capillary action of the bridge parts. This cooling effect is very high,
Furthermore, since the time required for cooling is quick, it is possible to prevent the temperature of the optical fiber from increasing and leading to damage. The temperature of the outer wick 151 rises when the working fluid liquefies from vapor, so in order to cool it, the outer wick 151 is heated with the outside of the tube 14,
The cooling liquid 19 is introduced between the outer cylinder 2 and the inlet 20. Outlet 21
Note that the tube 14 may be cooled by natural cooling with air or forced cooling with gas instead of the above-mentioned cooling method, if necessary.In order to increase the cooling effect, heat may be radiated to the outside of the tube 14. Fins may also be provided.

Effects of the invention The entire outer periphery of the optical fiber is in contact with the cooling liquid or magnetic fluid, so the thermal resistance from the optical fiber to the liquid is small, and the heat generated within the optical fiber is transferred through the cooling liquid or heat pipe working liquid and the magnetic fluid. The light is efficiently released to the surrounding area, suppressing the temperature rise inside the optical fiber.

Furthermore, since the optical fiber is held in liquid, it is hardly scratched, and no local mechanical pressure is applied, so no distortion occurs inside the optical fiber. Furthermore, the light guide fiber holder is integrally joined to the end of the tube and has a sealing effect against the cooling liquid inside the tube, so that one end of the optical fiber is always kept in place to prevent the cooling liquid from seeping out. It has the advantage of being able to be kept in good condition. In addition, in the case of the heat pipe method shown in Figure 3, the inside of the tube is completely sealed and the pressure can be highly reduced so that the working fluid can evaporate at a lower temperature, so the working fluid does not ooze out. This has the advantage that the cooling effect of the beet pipe can be further enhanced.

[Brief explanation of the drawing]

FIG. 1 is a sectional front view of a light guide device for optical power transmission in an embodiment of the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG.
The figure is a sectional front view of a light guide device for optical power transmission according to another embodiment of the present invention, FIG. 4 is a sectional view taken along the line C-C in FIG. 3, and FIGS. It is a sectional view of a light guide device. 1... Optical fiber, 2... Gas, 3
...Optical fiber, 6...Optical fiber, 7...Optical fiber holder, 1o...
... Cooling liquid, 11. Old... Ring-shaped magnet, 13...
...Magnetic fluid, 15...Wick, 16...
... Working fluid, 19... Cooling fluid. Name of agent: Patent attorney Toshio Nakao and one other person #!
Figure 1 Figure 2 Figure 3 Figure 5 Figure 6 a.

Claims (4)

[Claims] (1) An optical fiber holder composed of an optical fiber for optical power transmission, multiple pairs of magnetic poles and a magnetic fluid injected into the magnetic field formed by the magnetism, and an optical fiber holder that is coupled to the optical fiber holder and has an open end. A space formed by a tube whose aperture is larger than the optical fiber diameter and smaller than the outer diameter of the magnetic fluid, and the optical fiber excluding the holder, the tube, and the vicinity of the end is filled. A light guide device for transmitting optical power with a cooling liquid. (2) The light guide device for optical power transmission according to claim 1, characterized in that the tube has an inlet and an outlet for cooling liquid at both ends thereof, through which the cooling liquid flows. (3) An optical fiber holder composed of an optical fiber for optical power transmission, multiple pairs of magnetic poles and a magnetic fluid injected into the magnetic field formed by the magnetic poles, and an optical fiber holder that is coupled to the optical fiber holder and has an open end. A highly depressurized tube formed by a tube having an aperture larger than the optical fiber diameter and smaller than the outer diameter of the magnetic fluid, and the optical fiber except for the holder, the tube, and the vicinity of the end. a wick disposed on at least one of the inside of the tube and the outer periphery of the optical fiber in this space; an evaporative working fluid impregnated in the wick; and a heat radiation provided on the entire outside of the tube. 1. A light guide device for optical power transmission, characterized in that it is comprised of a vessel and a light guide device for optical power transmission. (4) The light guide for optical power transmission according to claim 3, wherein the wick is provided both inside the tube and on the outer periphery of the optical fiber, and has a large number of bridge parts connecting the two. Device.