JP2004004324A - Method for treating end of photonic crystal fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for treating the end of a photonic crystal fiber by which abrasives and chips are prevented from entering into the pores in a porous part when the end of the photonic crystal fiber is ground. <P>SOLUTION: The photonic crystal fiber 1 comprises a solid core part 2 forming the center of the fiber and a porous part 3 disposed in such a way as to enclose the core part 2 and having numerous pores 3a extending along the core part 2. Before grinding the end of the photonic crystal fiber 1, the openings of the pores 3a in the end of the fiber are blocked up with a blocking material 5, and after grinding the end of the fiber, the blocking material 5 blocking up the openings of the pores 3a is removed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a terminal processing method for a photonic crystal fiber.
[0002]
[Prior art]
The photonic crystal fiber includes a core portion formed solidly at the center of the fiber, and a porous portion provided to surround the core portion and having a large number of pores extending along the core portion. Such a photonic crystal fiber transmits light while confining light in a core portion surrounded by a porous portion, but can freely control the wavelength dispersion of light by changing the size and interval of pores. For this reason, communication in a new wavelength range, which cannot be realized by the conventional optical fiber, becomes possible, and high-speed communication and cost reduction are expected.
[0003]
[Problems to be solved by the invention]
When connecting the photonic crystal fiber to the connector, the fiber end face of the photonic crystal fiber is connected to the fiber end face of the connected fiber. However, when the end faces of the fibers are brought into contact with each other, if an air layer is formed between one fiber end face and the other fiber end face, light is reflected at the boundary between the core and the air layer, or However, there is a disadvantage that a part of light is lost. Therefore, the fiber end faces are polished so that there is no gap between the two fiber end faces. However, in the case of a photonic crystal fiber, since pores are formed in the porous portion, abrasives and polishing debris enter these pores during polishing, which deteriorates optical characteristics, or There is a problem in that it comes out of the pores and adheres to the core to cause obstacles such as hindering the propagation of light.
[0004]
Further, since the interval between the pores is very narrow, about 10 μm or less, there is also a problem that the porous portion is cracked or broken by vibration or impact during polishing.
[0005]
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a photonic crystal fiber in which a polishing agent or polishing debris does not enter the pores of the porous portion when polishing the fiber end face. It is an object of the present invention to provide a method for terminating a crystal fiber.
[0006]
[Means for Solving the Problems]
The invention according to claim 1 includes: a core portion that forms a center of a fiber and is solid; and a porous portion that is provided so as to surround the core portion and has a large number of pores extending along the core portion. In a method for processing the end of the photonic crystal fiber for polishing the fiber end face of the photonic crystal fiber provided,
Before polishing the fiber end face, the opening of the pore at the fiber end is closed with a blocking material, and after polishing the fiber end face, the plugging material blocking the opening of the pore at the fiber end is removed. It is characterized by being removed.
[0007]
According to the above method, before the fiber end face is polished, the openings of the pores are closed in advance with the plugging material. It is possible to prevent the abrasive or polishing debris or the like entering the hole from deteriorating the optical characteristics, and prevent the abrasive or the polishing debris or the like coming out of the pore from adhering to the core portion and hindering the propagation of light.
[0008]
Also, since the plugging material that closes the openings of the pores mitigates vibrations and shocks during polishing, it is necessary to avoid cracks and cracks between the pores in the porous portion of the fiber end face. Can be.
[0009]
Furthermore, since the plugging material that closes the openings of the pores is removed after the polishing is completed, there is no influence on the optical characteristics when actually using the photonic crystal fiber.
[0010]
According to a second aspect of the present invention, in the terminal processing method for a photonic crystal fiber according to the first aspect,
The closing material is any one of an acrylic resin, an epoxy resin, and a urethane resin.
[0011]
When the closing material is an acrylic resin, the acrylic resin is a thermoplastic resin, so that thermoforming is possible, and it is easy to close an opening of a pore having a diameter of several μm, and to remove the same. Is easy to do. In addition, the acrylic resin is susceptible to acid, and by using this property, it is possible to remove the plugging material from the pores.
[0012]
When an epoxy resin is used as the plugging material, it is possible to cure the epoxy resin in an uncured state in a short time by pouring it into the pores and then heating it. The epoxy resin is hydrolyzed by an alkali when an acid curing agent is used as a curing agent contained therein, and is hydrolyzed by an acidic substance when an amine curing agent is used. Therefore, by using this, it is possible to easily remove the plugging material from the pores.
[0013]
Currently, urethane-based resins that are thermoplastic and soluble in solvents have been developed. When this is used as a closing material, a molding operation for closing the opening of the pore is easy. Further, as a method of removing this from the pores, it is possible to dissolve it in an appropriate solvent and remove it from the pores.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the following embodiments.
[0015]
(Embodiment 1)
FIG. 1 shows a terminal portion of a photonic crystal fiber 1 according to Embodiment 1 of the present invention.
[0016]
The photonic crystal fiber 1 is formed of quartz, plastic, or the like, and has a core 2 serving as the center of the fiber, a porous portion 3 provided so as to surround the core 2, and a porous portion 3 surrounding the core 3. And a covering portion 4 provided.
[0017]
The core portion 2 is formed solid, and may be doped with a functional material such as germanium (Ge). The optical signal is transmitted along the core 2 along the longitudinal direction.
[0018]
The porous portion 3 is formed with a plurality of pores 3a extending along the core portion 2 so as to form a triangular lattice in the cross section of the fiber, and the plurality of pores 3a form a photonic crystal structure in the fiber radial direction. Has formed. The optical signal is confined in the core part 2 by the porous part 3.
[0019]
Such a photonic crystal fiber 1 is manufactured as follows.
[0020]
First, a preform is prepared in which a cylindrical support tube is filled with a plurality of capillaries and one core member. At this time, the core member is arranged at the center axis position.
[0021]
Next, the preform is set in a drawing machine, and is heated to a high temperature and stretched at a high speed to reduce the diameter (to form a fiber).
[0022]
A method for terminating the photonic crystal fiber 1 will be described.
[0023]
As shown in FIG. 2A, the photonic crystal fiber 1 manufactured as described above has an uneven end face.
[0024]
Into the photonic crystal fiber 1, first, a thermoplastic acrylic resin melted by heating is injected as a plugging material 5 into the pores 3 a of the porous portion 3 at the fiber end, and FIG. As shown, it is cooled to close the pores 3a of the porous portion 3.
[0025]
Next, the end face of the photonic crystal fiber 1 is polished using a polishing machine or the like, and as shown in FIG. 2C, the end face of the fiber is formed perpendicular to the fiber axis.
[0026]
Next, as shown in FIG. 2D, the coating 4 at the fiber end is polished with a polishing machine to form a taper so that the coating 4 does not interfere with the fiber end.
[0027]
Finally, as shown in FIG. 2E, the acrylic resin as the closing material 5 that has closed the pores 3a of the porous portion 3 is removed.
[0028]
As shown in FIGS. 3 and 4, a connector 6 is attached to the end of the photonic crystal fiber 1 that has been subjected to such a terminal treatment, and is connected to the optical fiber 7 to be connected.
[0029]
According to the above-described method for processing the end of the photonic crystal fiber 1, the opening of the pore 3a is closed with the closing material 5 before polishing the fiber end face. Does not enter the pores 3a, and the abrasive or polishing debris that has entered the pores 3a deteriorates the optical characteristics, or the abrasive or polishing debris that has come out of the pores 3a adheres to the core portion 2. It is possible to prevent light from propagating.
[0030]
In addition, since the plugging material 5 that closes the opening of the pore 3a reduces the vibration and impact during polishing, a crack is formed or broken between the pore 3a and the pore 3a in the porous portion 3 at the end face of the fiber. Can be avoided.
[0031]
Further, since the plugging material 5 that blocks the opening of the pore 3a is removed after the polishing is completed, when the photonic crystal fiber 1 is actually used, it does not affect the optical characteristics.
[0032]
In addition, an acrylic resin is used as the closing material 5, and since the acrylic resin is a thermoplastic resin, thermoforming is possible, and the work of closing the opening of the pore 3a having a diameter of several μm is easy. , And the work of removing it is easy. The acrylic resin is vulnerable to acid, and it is possible to remove the blocking material 5 from the pores 3a by utilizing this property.
[0033]
(Embodiment 2)
The terminal processing method of the photonic crystal fiber 1 of the second embodiment is similar to that of the first embodiment, except that an epoxy resin is used as the closing material 5 for closing the opening of the pore 3a.
[0034]
An uncured liquid epoxy resin is poured into the pores 3a of the porous portion 3, and the opening is closed by heating to cure the epoxy resin. After that, the fiber end face is polished as in the first embodiment. After the polishing is completed, the epoxy resin as the closing material 5 that has closed the opening of the pore 3a of the porous portion 3 is removed from the pore 3a.
[0035]
According to the terminal treatment method of the photonic crystal fiber 1 described above, the epoxy resin is used as the plugging material 5, and the uncured liquid epoxy resin is poured into the pores 3a and then heated for a short time. It is possible to cure it. The epoxy resin is hydrolyzed by an alkali when an acid curing agent is used as a curing agent contained therein, and is hydrolyzed by an acidic substance when an amine curing agent is used. Therefore, by using this, it is possible to easily remove the plugging material 5 from the pores 3a.
[0036]
Other functions and effects are the same as those of the first embodiment.
[0037]
(Embodiment 3)
The method for terminating the photonic crystal fiber 1 of the third embodiment is similar to that of the first embodiment, except that a urethane resin is used as the closing material 5 for closing the opening of the pore 3a.
[0038]
A thermoplastic urethane-based resin heated and melted into the pores 3a of the porous portion 3 is injected as a closing material 5, and then cooled to close the pores 3a of the porous portion 3. Thereafter, the fiber end face is polished as in the first embodiment. After the polishing is completed, the urethane-based resin that has closed the opening of the pore 3a is removed from the pore 3a.
[0039]
According to the above-described method for processing the end of the photonic crystal fiber 1, since the thermoplastic urethane resin is used as the plugging material 5, the molding operation for closing the opening of the pore 3 a is easy. In addition, as a method for removing this from the pores 3a, it is possible to dissolve it in an appropriate solvent and remove it from the pores 3a.
[0040]
Other functions and effects are the same as those of the first embodiment.
[0041]
【The invention's effect】
According to the first aspect of the present invention, the opening of the pore is closed with the closing material before the fiber end face is polished. Therefore, when polishing the fiber end face, an abrasive or polishing debris enters the pores. Can be prevented. In addition, since the plugging material reduces vibration and impact generated during polishing, damage such as cracking or breaking of the porous portion 3 can be prevented. Furthermore, the plugging material that blocks the openings of the pores is removed after the polishing is completed, so that the photonic crystal fiber 1 does not affect the optical characteristics when actually used.
[0042]
According to the invention according to claim 2, since any one of the acrylic resin, the epoxy resin, and the urethane resin is used as the closing material, the processing for closing the opening of the pore is easy, Also, its removal can be performed relatively easily.
[Brief description of the drawings]
FIG. 1 is a perspective view of a photonic crystal fiber according to a first embodiment.
FIG. 2 is an explanatory diagram for explaining a method of treating an end portion of a photonic crystal fiber in a II-II section in FIG. 1;
FIG. 3 is a diagram showing a first connection structure between a photonic crystal fiber and a connected optical fiber.
FIG. 4 is a diagram showing a second connection structure between a photonic crystal fiber and a connected optical fiber.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Photonic crystal fiber 2 Core part 3 Porous part 3a Pores 4 Coating part 5 Closure material 6 Connector 7 Optical fiber to be connected

Claims (2)

A fiber of a photonic crystal fiber, comprising: a core part which forms a center of a fiber and is solid; and a porous part which is provided so as to surround the core part and has a large number of pores extending along the core part. In a terminal processing method of a photonic crystal fiber for polishing an end face,
Before polishing the fiber end face, the opening of the pore at the fiber end is closed with a blocking material, and after polishing the fiber end face, the plugging material blocking the opening of the pore at the fiber end is removed. A method for processing a terminal of a photonic crystal fiber, which comprises removing the fiber. The method for terminating a photonic crystal fiber according to claim 1,
The method for processing a terminal of a photonic crystal fiber, wherein the closing material is one of an acrylic resin, an epoxy resin, and a urethane resin.

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