JP3986016B2 - End face processing method for optical fiber with holes - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for treating an end face of a holey optical fiber.
[0002]
[Prior art]
A conventional optical fiber is composed of a core in the center and a clad around the core and having a refractive index lower than that of the core, and light propagates in the core. This optical fiber did not have a hole.
In an optical network using this optical fiber, an optical connector, a receptacle, or the like is used when optical fibers are optically connected to each other or to an optical communication device. Here, since the core of the optical fiber has a very fine shape, it is required that the core of the optical fiber be abutted with high accuracy when connecting an optical connector or a receptacle. Therefore, after fixing a ferrule etc. to an optical fiber, the end surface of this ferrule is grind | polished using the grinder (for example, refer nonpatent literature 1 and nonpatent literature 2).
At this time, foreign matters such as optical fiber scraps, abrasive scraps, and ferrule scraps may be generated and adhere to the end face of the optical fiber. Since the end face of the optical fiber is wiped with a specific solvent or cleaned with an ultrasonic cleaner or the like, the foreign matter adhering to the end face of the optical fiber is completely removed. For this reason, almost no connection loss of the optical connector due to the foreign matter occurred.
[0003]
Currently, the amount of information communication transmitted in an optical network is increasing. Therefore, in order to provide subscribers with a service capable of high-speed and large-capacity information communication, access-system optical communication facilities are capable of communicating larger volumes of information than conventional optical fibers, such as low nonlinearity and An optical fiber having a precisely adjusted chromatic dispersion characteristic has been developed.
[0004]
On the other hand, a newly developed optical fiber with a hole (hole) (for example, see Non-Patent Document 3) has a structure having a hole in the longitudinal direction of the optical fiber, and has low loss, low dispersion, and low nonlinear characteristics. In the future, future development is drawing attention. The diameter of the optical fiber with a hole is from 125 μm to several hundred μm, and the diameter of the hole provided in the optical fiber with a hole is from several μm to several tens μm or less, which is a very fine shape.
[0005]
[Non-Patent Document 1]
Supervised by Atsushi Ishihara, “Points of Optical Fiber Technology 200”, Telecommunications Association, March 20, 1997, p. 258
[Non-Patent Document 2]
Kenichi Nishimura, Hidetoshi Shirakawa, “Easy Fiber Optic Communication”, Telecommunications Association, January 20, 1992, p. 81-82
[Non-Patent Document 3]
Takeshi Hasegawa, “Holy Fiber Outlook”, magazine “O plus E”, vol. 123, no. 9, September 2001, p. 1067-1071
[0006]
[Problems to be solved by the invention]
When laying the optical fiber with a hole in an optical network, it is necessary to provide an optical connector in which a ferrule is fixed to the end of the optical fiber with a hole, as in the conventional optical fiber. After the ferrule is fixed to the optical fiber with a hole, if the end surface of the ferrule is polished using a general polishing machine, foreign matter is generated as in the case of polishing the end surface of the ferrule fixed to the conventional optical fiber. As a result, the foreign matter adheres to the end face of the holey optical fiber or enters the hole of the holey optical fiber.
[0007]
Therefore, as in the case of cleaning the end face of the optical fiber described above, the end face of the optical fiber with a hole is wiped with a specific solvent, or is cleaned with an ultrasonic cleaner or the like. However, foreign matter that has entered the hole of the optical fiber with a hole cannot be removed, and even if an ultrasonic cleaner that is more powerful than an ultrasonic cleaner used at the site of laying construction (can be carried) is used, Foreign matter that has entered the hole of the optical fiber with a hole cannot be completely removed.
For this reason, foreign matter remains in the hole of the optical fiber with a hole, and when this optical fiber with a hole is connected to a normal optical fiber, another optical fiber with a hole, or an optical communication device, a connection loss occurs. Cause. Therefore, there is a problem that the intensity of light propagating in the optical network is attenuated.
In addition, if a foreign object enters the hole of a holey optical fiber, the characteristics of the holey optical fiber can be measured more accurately, or the characteristics necessary to develop a higher performance holey optical fiber can be measured. There is also a problem that it cannot be done.
[0008]
The present invention has been made to solve the above-described problems, and provides a method for processing an end surface of an optical fiber with a hole, which is based on a conventional technique for processing an end surface of an optical fiber as much as possible and includes simple operations. With the goal.
[0009]
[Means for Solving the Problems]
According to a first aspect of the present invention for solving the above-mentioned problem, a hole optical fiber end face processing method is provided with a lid formed by putting water into an end portion of a hole of an optical fiber with a hole and freezing the water. Forming the end of the fiber, polishing the end face of the optical fiber with a hole, and then heating the optical fiber with the hole to expand the gas in the hole of the optical fiber with the hole to cover the lid from the hole It is characterized by discharging.
According to the method for treating an end face of a holey optical fiber according to the present invention, a lid formed by freezing water by putting water into the hole end of the holey optical fiber is formed at the end of the holey optical fiber. Foreign matter such as optical fiber debris generated when the end face of the holey optical fiber is polished does not enter the hole of the holey optical fiber.
[0010]
The method for treating an end face of an optical fiber with a hole according to a second invention for solving the above-described problem is the method for treating an end face of the optical fiber with a hole in the first invention before the water is put into the end of the hole of the optical fiber with a hole. Water or alcohol is put into the hole of the fiber, and a layer made of the water or alcohol is formed in the hole of the optical fiber with a hole.
According to the method for treating an end face of a holey optical fiber according to the present invention, since a layer made of water or alcohol is formed in the hole of the holey optical fiber, the volume expansion due to vaporization of water or alcohol by raising the temperature. Can be used as a powerful force for discharging water from the optical fiber with holes.
[0011]
The method for treating an end face of a holey optical fiber according to a third aspect of the present invention that solves the above-described problem is the first aspect of the invention, in which the holed light is introduced before the water is poured into the end of the hole of the holey optical fiber. It is characterized by raising the temperature of the fiber.
According to the method for treating an end surface of an optical fiber with a hole according to the present invention, the temperature of the optical fiber with a hole is increased before the water is put into the end of the hole of the optical fiber with a hole. There is a difference, and a larger volume shrinkage force can be obtained.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments relating to the method for treating an end face of a holey optical fiber according to the present invention will be described below.
[0014]
FIG. 1 is a schematic view of a holey optical fiber and an optical connector applied to an end face processing method according to the present invention. FIG. 2 is a perspective view showing one step of an embodiment of the end surface processing method according to the present invention. FIG. 3 is a perspective view showing one step of an embodiment of the end surface processing method according to the present invention. FIG. 4 is a plan view of one process of an embodiment of the end surface processing method according to the present invention. FIG. 5 is a cross-sectional view of a holey optical fiber in one step of an embodiment of an end face processing method according to the present invention. FIG. 6 is a perspective view of one step of an embodiment of the end surface processing method according to the present invention. FIG. 7 is an enlarged view of an end portion of the optical fiber with a hole.
[0015]
The end face processing method of the optical fiber 1 with a hole is roughly divided into the following three operations. That is, the pre-processing work for the optical fiber 1 with holes, the polishing work for the end face of the optical fiber 1 with holes, and the post-processing work for the optical fiber 1 with holes.
Here, as shown in FIG. 1, description will be made using an optical fiber 1 with a hole provided with optical connectors 3 made of ferrules at both ends.
[0016]
First, in the pretreatment operation of the optical fiber 1 with holes, as shown in FIG. 2, both ends of the optical fiber 1 with holes, that is, the optical connector 3 are put into a beaker 6 filled with water 5. At this time, the amount of water 5 stretched on the beaker 6 is such that the optical connector 3 is sufficiently immersed. Thereafter, the vicinity of the center of the optical fiber 1 with holes is cooled, the gas in the holes 2 (see FIG. 5) is contracted, and water 5 is put into the holes 2 (suctioned).
Moreover, as a method of putting water 5 into the hole 2 of the optical fiber 1 with a hole, the water 5 may be put into the hole 2 of the optical fiber 1 with a hole by utilizing a capillary phenomenon, or for each end face of the optical fiber 1 with a hole. Water 5 may be added to the tank.
A certain amount of water 5 is put into the hole 2 of the optical fiber 1 with a hole, and the optical fiber 1 with a hole is taken out from the beaker 6. However, the optical fiber with a hole is provided so that the water 5 does not leak from the hole 2 of the optical fiber 1 with a hole, that is, the optical fiber 1 with a hole is warmed so that the pressure in the hole 2 does not become higher than normal pressure. Pay attention to the handling of 1.
[0017]
In addition, before putting the both ends of the optical fiber 1 with a hole into the beaker 6 in which the water 5 was stretched, the optical fiber 1 with a hole may be stored in a high temperature thermostat and heated. By heating the optical fiber 1 with a hole, the temperature of the gas in the hole 2 rises. Therefore, the volume contraction force of the gas in the hole 2 obtained when the holed optical fiber 1 is cooled from a state where the temperature is raised is that of the hole 2 obtained when the holey optical fiber 1 is cooled at room temperature. Since it becomes larger than the volume contraction force of the gas inside, the water 5 can be easily put into the hole 2 of the optical fiber 1 with a hole. Furthermore, in the post-processing operation of the optical fiber 1 with holes, which will be described later, ice formed by cooling water in the holes 2 of the optical fiber 1 with holes can be easily discharged.
[0018]
Then, as shown in FIG. 3, the optical fiber 1 with a hole is put into a low-temperature thermostatic bath 7 and cooled to freeze water in the hole 2 of the optical fiber 1 with a hole, as shown in FIG. The lid made of ice 9 is formed at both ends of the hole 2 of the optical fiber 1 with a hole. In addition, the water in the hole 2 of the holey optical fiber 1 is frozen by cooling the holey optical fiber 1 using alcohol or liquid nitrogen cooled with solid carbon dioxide instead of the low temperature constant temperature bath 7. You may let them.
[0019]
Subsequently, in the polishing operation of the end face of the optical fiber 1 with a hole, one end face of the optical fiber 1 with a hole is taken out from the low-temperature constant temperature bath 7 and this end face is polished. At this time, the other end face of the optical fiber 1 with a hole is in the low-temperature thermostatic chamber 7. Although foreign substances such as optical fiber scraps, abrasive scraps, and ferrule scraps are generated by polishing, since the end of the hole 2 of the optical fiber 1 with a hole has an ice lid, the foreign substance does not enter the hole 2. The other end face of the optical fiber 1 with a hole is also taken out from the low-temperature constant temperature bath 7, and the end face is similarly polished.
[0020]
Subsequently, in the post-processing operation of the optical fiber 1 with holes, when the temperature during the operation is low, the optical fiber 1 with holes is placed on a heater such as a hot plate 8 and heated as shown in FIG. By heating, the ice surface in the hole 2 of the optical fiber 1 with a hole melts, and the friction coefficient between the inner surface of the hole 2 and the ice decreases. Furthermore, the temperature of the gas in the hole 2 of the optical fiber 1 with a hole rises, and this gas expands. As a result, ice is discharged from the hole 2 of the optical fiber 1 with a hole. At this time, foreign matter such as optical fiber debris adhering to the end face of the holey optical fiber 1 is also discharged together with ice.
On the other hand, the foreign matter adhering to the periphery of both ends of the optical fiber 1 with holes is removed by wiping with a specific solvent or cleaning with an ultrasonic cleaner or the like, as in the conventional cleaning method.
[0021]
In addition, the size of the foreign matter generated when the end face of the holey optical fiber 1 is polished is 1 mm or less, and there are linear ones. That is, the diameter of the foreign material is smaller than the diameter of the hole 2 of the optical fiber 1 with a hole, and the axial length of the foreign material is 1 mm or less at the maximum. For example, even if this foreign substance enters the hole 2 of the optical fiber 1 with a hole, if about 10 mm of water is put into the hole 2 of the optical fiber 1 with a hole and cooled to freeze, When the optical fiber 1 is heated, since the ice is larger than the foreign matter, the foreign matter is discharged together with the ice.
[0022]
Further, when the holey optical fiber 1 is heated, the amount of ice 9 discharged from the hole 2 may vary from hole 2 to hole 2 as shown in FIG. Also at this time, since the foreign material 10 is as small as 1 mm or less as described above, the foreign material 10 can be easily removed as long as it comes out of the hole 2 of the optical fiber 1 with a hole. As shown in FIG. 6, the discharge amount of the ice 9 is different for each hole 2, and even if the ice 9 is discharged from one hole 2, the gas in the other hole 2 expands by heating. . This is because the holes 2 of the optical fiber 1 with holes are independent one by one as shown in FIG.
Further, water may remain in the hole 2 of the optical fiber 1 with a hole. At this time, when the optical fiber 1 with holes is left as it is for a while or heated for a while with the hot plate 8 or the like, water becomes steam and is discharged out of the optical fiber 1 with holes.
[0023]
Therefore, the foreign material 10 which arises by the end surface process of the optical fiber 1 with a hole can be removed easily. Furthermore, since no special tools are required, it is economical.
[0024]
In the present embodiment, water is used as the amorphous material, but instead of water, the state changes from liquid to solid, and from solid to liquid or gas due to temperature change, light irradiation, chemical dripping, etc. In addition, any amorphous material that is viscous at room temperature and dissolves in water or the like may be used. For example, rubber, thermoplastics, paraffin, and water tanks may be used. Further, in the post-processing operation of the optical fiber 1 with a hole, if these amorphous substances cannot be removed from the hole 2 even if the optical fiber 1 with a hole is heated, it is cleaned with an ultrasonic cleaner. If the temperature of the optical fiber 1 with a hole is lowered while the both ends of the optical fiber 1 with a hole are immersed in the cleaning liquid of an ultrasonic cleaner, the pressure in the hole 2 becomes low, and the cleaning liquid enters the hole 2 The amorphous material can be completely removed from the hole 2.
[0025]
In the present embodiment, a method of discharging ice in the hole 2 of the holey optical fiber 1 using the thermal expansion of the gas in the hole 2 of the holey optical fiber 1, that is, the thermal expansion of air, is described. However, before carrying out the pretreatment operation of the optical fiber 1 with holes, that is, before both ends of the optical fiber 1 with holes 5 are put into the beaker 6 filled with water 5, the holes 2 of the optical fiber 1 with holes are inserted. Water or ethanol may be added.
[0026]
Specifically, water is put into one end face of the holey optical fiber 1 to freeze and seal, and the other end face of the holey optical fiber 1 is put into a beaker filled with water or ethanol. Thereafter, the optical fiber 1 with holes is cooled, the gas in the hole 2 of the optical fiber 1 with holes is contracted, and water or ethanol is put into the hole 2 of the optical fiber 1 with holes. After a certain amount of water or ethanol is put into the hole 2 of the optical fiber 1 with a hole, this end face is taken out from the beaker, the optical fiber 1 with a hole is further cooled, air is introduced into this end face, and light with a hole is obtained. Layers of air are formed on both ends of the fiber 1.
Therefore, at the time of polishing the end face of the optical fiber 1 with holes, five layers made of ice, air, water or ethanol, air, and ice are formed from the end face of the optical fiber 1 with holes.
[0027]
According to this method, when the optical fiber 1 with holes is heated in the post-processing operation of the optical fiber 1 with holes, the volume expansion rate due to the vaporization of water or ethanol in the holes 2 of the optical fiber 1 with holes is air. Therefore, the ice 9 containing the foreign material 10 can be easily discharged from the hole 2 of the optical fiber 1 with a hole.
[0028]
【The invention's effect】
As described above in detail with the embodiments of the invention, according to the method for treating an end surface of an optical fiber with a hole according to the present invention, the foreign matter generated when the end surface of the optical fiber with a hole is polished is light with a hole. Since there is a lid made of solid amorphous material at the end of the fiber hole, it does not get into the hole. Also, by heating the holey optical fiber, the layer of gas, water, or ethanol in the hole of the holey optical fiber is thermally expanded. Foreign matter adhering to the end face of the attached optical fiber can also be discharged. In addition, the volume shrinkage force of the gas obtained when cooling the holey optical fiber by raising the temperature of the holey optical fiber before putting the amorphous substance into the end of the hole of the holey optical fiber. However, since it is larger than the volumetric shrinkage force of the gas obtained when the optical fiber with holes at room temperature is cooled, an amorphous substance can be easily put into the end of the hole of the optical fiber with holes.
Therefore, by simply adding a simple operation to the conventional optical fiber end face processing, it is possible to perform the end face processing of the optical fiber with a hole without using any special equipment or special work. The end surface processing itself is simple and economical.
Moreover, since water can be easily obtained by using water as an amorphous substance, it is economical.
[0029]
In addition, since foreign matter such as optical fiber debris generated when processing the end face of the optical fiber with a hole does not enter the hole of the optical fiber with a hole, the characteristics of the optical fiber with a hole can be measured more accurately, It is possible to measure the characteristics required to develop a high performance holey optical fiber.
[Brief description of the drawings]
FIG. 1 is a schematic view of an optical fiber with a hole and an optical connector applied to an end face processing method according to the present invention.
FIG. 2 is a perspective view showing one step of an embodiment of an end surface processing method according to the present invention.
FIG. 3 is a perspective view showing one step of an embodiment of the end face processing method according to the present invention.
FIG. 4 is a plan view of a step of an embodiment of the end surface processing method according to the present invention.
FIG. 5 is a cross-sectional view of a holey optical fiber in one step of an embodiment of an end face processing method according to the present invention.
FIG. 6 is a perspective view of one step of an embodiment of the end surface processing method according to the present invention.
FIG. 7 is an enlarged view of an end portion of the optical fiber with a hole.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Optical fiber with a hole 2 Hole 3 Optical connector 5 Water 6 Beaker 7 Low temperature thermostat 8 Hot plate 9 Ice 10 Foreign material

Claims (3)

A lid formed by putting water into the hole end of the holed optical fiber and icing the water is formed at the end of the holed optical fiber, the end surface of the holed optical fiber is polished, and then the holed A method of treating an end face of an optical fiber with a hole, wherein the optical fiber is heated to expand a gas in the hole of the optical fiber with a hole to discharge the lid from the hole.   2. The optical fiber with a hole according to claim 1, wherein before the water is put into an end of the hole of the optical fiber with a hole, water or alcohol is put into the hole of the optical fiber with a hole to form the layer made of the water or alcohol. A method of treating an end face of an optical fiber with a hole, characterized in that the optical fiber is formed in a hole.   2. The method for treating an end face of a holey optical fiber according to claim 1, wherein the temperature of the holey optical fiber is raised before the water is put into the end of the hole of the holey optical fiber.

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