JP4100966B2 - Fusion splicing method of optical fiber - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical fiber fusion splicing method, and more particularly, to a method of re-coating a portion of a spliced connection of an optical fiber from which a coating portion has been removed.
[0002]
[Prior art]
In the fusion splicing of optical fibers frequently used in the field of optical communications, first, the coating of the ends of the two optical fiber core wires to be connected is removed to expose the bare fibers, which are then cleaned and cleaved. Then, the cleavage planes are made to face each other, the bare fibers are fused together, and finally the bare fibers in the connection portion are recoated with a resin.
[0003]
In this case, the re-covering of the connecting portion is performed as follows using the apparatus shown in FIG .
[0004]
First, one recoating die 22a is placed on the die table 21 in which the ultraviolet light guide 26 is inserted. Next, the optical fiber core wire 23 that has been fusion spliced and from which the coating of the fusion splicing portion has been partially removed is gripped by holders (not shown) installed at the top and bottom of the apparatus. Thereafter, the other recoating die 22b is combined with the recoating die 22a, and an ultraviolet curable resin is filled into the tapered groove portion 25 of the die formed thereby.
[0005]
Then, the die table 21 is raised while irradiating the ultraviolet light through the ultraviolet light guide 26, and the fusion spliced portion of the optical fiber core wire 23 is coated and cured with the ultraviolet curable resin, and the exposed portion is recoated ( Recoat). At this time, the die table 21, the recoating dies 22a and 22b, and the ultraviolet light guide 26 operate integrally.
[0006]
[Problems to be solved by the invention]
However, in the above-described re-coating method using the apparatus shown in FIG. 3 , when the die 22 is raised during re-coating, bubbles are likely to remain at the time of peeling the optical fiber core wire (the end of the peeled coating). There is a problem. When the optical fiber core wire is peeled off, it becomes jagged when the coating is peeled off, and bubbles tend to remain in that portion.
[0007]
If air bubbles remain during peeling, excessive stress is applied to the optical fiber due to expansion and contraction of the air bubbles when the temperature changes, and the optical fiber may be broken or transmission loss may increase.
[0008]
An object of the present invention is to provide an optical fiber fusion splicing method which is made under such circumstances and effectively prevents air bubbles from being mixed during re-coating after the optical fiber fusion splicing. .
[0009]
[Means for Solving the Problems]
To solve the above problems, the present invention removes the coating of fusion splice a pair of optical fibers to be connected, the cover is arranged opposite the ends of the bare fibers removed fusion wearing connected, a fusion splicing method for recoating (recoating) optical fiber onto said fusion connected bare fiber,
The fusion spliced connection portion is completely stripped of the coating corresponding to the portion to be recoated to form a bare bare fiber portion,
A droplet of the first UV curable resin having a low viscosity is attached to the vicinity of the boundary between the bare fiber portion of the optical fiber core and the coating portion at one end thereof, and cured by irradiating with UV rays. After letting
Similarly, in the vicinity of the boundary portion between the bare fiber portion and the covering portion at the other end, a droplet of the first ultraviolet curable resin having a low viscosity is attached by hanging, and cured by irradiating with ultraviolet rays,
Then, a method for fusion splicing of an optical fiber is provided, in which a second ultraviolet curable resin is recoated .
[0010]
In the fusion splicing method of optical fibers according to the present invention, the first ultraviolet curable resin adhered to the vicinity of the boundary with the coating portion of the bare fiber and cured by irradiating with ultraviolet rays, and the second ultraviolet ray to be recoated The curable resin is preferably made of the same substance .
[0011]
The outline of the method of attaching the first ultraviolet curable resin in the vicinity of the boundary portion between the fusion-bonded bare fiber and the covering portion is as follows .
[0012]
(1) A droplet of the first ultraviolet curable resin is attached to the vicinity of the boundary between the bare fiber portion of the optical fiber core wire arranged vertically and the coating portion at one end thereof by dripping.
Thereafter, it is cured by irradiation with ultraviolet rays.
[0013]
(2) Next, in the same manner as in (1) above, a droplet of the first ultraviolet curable resin is attached to the vicinity of the boundary between the bare fiber portion and the coating portion at the other end by dripping .
Thereafter, it is cured by irradiation with ultraviolet rays.
[0014]
The first ultraviolet curable resin and the first ultraviolet curable resin are preferably the same substance, but may be different substances as long as the adhesion between the two is good. Examples of the ultraviolet curable resin include 950- (manufactured by DSM), Northland No. 68 (manufactured by Northland). Moreover, when employ | adopting the method of said (1), it is desirable for the 1st ultraviolet curable resin to be a thing with comparatively low viscosity from the ease of dripping.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0016]
The present invention is characterized in that an ultraviolet curable resin is attached in advance to the fusion-bonded optical fiber core wire (in the vicinity of the boundary with the coating portion) before re-coating. As described above, there are two methods for attaching the ultraviolet curable resin when the optical fiber core is peeled. First, referring to FIG. 1, the method (1) is used. explain.
[0017]
As shown in FIG. 1 (a), the ends of the bare fibers 3 from which the coating 2 of the optical fiber core wire 1 that has been spliced and connected are fusion spliced together, and then UV cured along the side surface of the coating 2 When the liquid crystal resin droplet 4 is dropped, the droplet 4 travels along the bare fiber 3 from the side surface of the coating 2 and is spotted when the bare fiber 3 is peeled off as shown in FIG.
[0018]
The dotted ultraviolet curable resin is then cured by irradiating with ultraviolet rays.
[0019]
Next, the optical fiber core wire 1 is turned upside down, and the ultraviolet curable resin droplet 4 is dropped along the side surface of the coating 2 in the same manner as described above to peel off the bare fiber 3 that is not dotted. The structure shown in FIG. 1B is obtained by staking and curing by irradiation with ultraviolet rays. Reference numerals 4a and 4b denote ultraviolet curable resins that are spotted and hardened when the bare fiber 3 is peeled off.
[0020]
Thereafter, as shown in FIG. 1 (c), the entire bare fiber 3 is coated with an ultraviolet curable resin 5 by an ordinary re-coating process, and cured by irradiating with ultraviolet rays, whereby an optical fiber fusion splicing process is performed. Is completed.
[0025]
According to the above method, before re-coating the ultraviolet curable resin, the ultraviolet curable resin is spotted in advance when the bare fiber 3 is peeled off. Air bubbles are prevented from remaining when the fiber 3 is peeled off. In particular, it is possible to reliably prevent bubbles from remaining when the bare fiber 3 is peeled off by irradiating the ultraviolet curable resin with ultraviolet rays after curing, and then performing a recoating process.
[0026]
Next, an optical fiber fusion splicing method according to a specific example of the embodiment of the present invention described above will be described with reference to FIG .
[0027]
First, the coating 12 at the connection end of the optical fiber core wire 11a shown in FIG. 2 (a) is peeled off as shown in FIG. 2 (b) to expose the bare fiber 13a. Next, as shown in FIG. 2C , the bare fiber 13a is cleaved and cut at a position. In FIG. 2C , reference numeral 15 indicates a cleavage cut surface. The other optical fiber core wire 11b to be fusion-bonded is subjected to the same processing to expose the bare fiber 13b and cleave it at a predetermined position.
[0028]
Next, the bare fiber 13a of the connection end portion In this way, 13b Gaseki open cut optical fiber 11a, a 11b, by using the fusion device shown in FIG. 2 (d), fusion splicing. The fusion apparatus includes members 16a and 16b that are movable in the X, Y, and Z directions, and the movable members 16a and 16b are provided with V-grooves.
[0029]
First, the optical fibers 11a and 11b are mounted in the V-grooves of the moving members 16a and 16b, and the cleavage surfaces of both are opposed to each other. Then, the optical fibers 11a and 11b are pressed by the fiber holders 17a and 17b. Thereafter, the movable members 16a and 16b are moved in the X, Y, and Z-axis directions to align the optical fibers 11a and 11b.
[0030]
Next, discharge is performed between the electrode rods 18a and 18b, and the movable members 16a and 16b are moved so as to be pushed in the X direction while melting the opposed portions of the opposed bare fibers 13a and 13b. As a result, as shown in FIG. 3E, the optical fiber core wires 11a and 11b are fusion-connected.
[0031]
The optical fiber core wire thus fused and spliced is then spotted with an ultraviolet curable resin when the bare fibers 13a and 13b are peeled off. The dotted ultraviolet curable resin is then cured by irradiating with ultraviolet rays. The dotted ultraviolet curable resin can be performed by the method shown in FIG. 1 described above (a). That is, a method of dripping the UV curable resin along the covering portion of the vertically disposed optical fiber is taken.
[0032]
The amount of the ultraviolet curable resin to be dotted may be an amount that allows the ultraviolet curable resin to spread throughout the bare fiber when it is peeled off. Moreover, the kind of ultraviolet curable resin to be marked was the same as that used for re-coating.
[0033]
In this way, the portion of the bare fiber that has been coated with the UV curable resin when the bare fiber is peeled is then recoated by a recoating process.
The recoating can be performed by a vertical recoating apparatus as shown in FIG . Hereinafter, the re-covering procedure will be described.
[0034]
First, ultraviolet curable resin is accommodated in the syringe for dispensers, and centrifugal defoaming is carried out. Next, the ultraviolet light source and the recoat apparatus are turned on. Here, it is confirmed that the dice table 21 of the recoating apparatus is at the bottom, and if it is above, it is brought into a state at the bottom by the lowering switch.
[0035]
Next, the large die 22 is cleaned with an ultrasonic cleaner and mounted on the die table 21. Then, the fusion-spliced optical fiber 23 is disposed so that the end of the covering portion 24 protrudes about 5 mm above the bottom of the tapered groove 25 of the large die 22 as shown in FIG. (Not shown).
[0036]
Next, a small die (not shown) is cleaned with an ultrasonic cleaner and mounted on the large die. Then, using a dispenser, drop 2 drops of UV curable resin on the side of the die table and 1 drop from the top of the fiber. After the UV curable resin hangs down to the bottom of the die and stops moving after about 20 seconds, the UV cover (not shown) is closed.
[0037]
Thereafter, the raising switch of the recoating apparatus is turned on to raise the die table 21, and at the same time, the ultraviolet light is irradiated through the ultraviolet light guide 26. Then, after removing the small dice and wiping with a bencott containing ethanol, the dice are washed with an ultrasonic cleaner.
[0038]
Next, the fiber holder is released and the optical fiber 23 is removed.
After removing the large die 22 and wiping with ethanol containing bencott, it is cleaned with an ultrasonic cleaner, and the re-coated portion of the optical fiber 23 is lightly wiped with bencott. Then, the lowering switch of the recoat apparatus is turned on to lower the die table 21.
[0039]
Next, the re-covering operation is completed by repeating the above-described operations after the large die is mounted except that a large die (not shown) having a different size is used and the optical fiber 23 is disposed upside down.
[0040]
When the appearance of the recoated portion of the optical fiber in which the portion of the bare fiber spliced as described above was recoated was examined using a loupe, no abnormality was found. In addition, a transmission test was conducted using the optical fiber spliced in this way, and the transmission loss was very small.
[0041]
Incidentally, recoating operation is not limited to the vertical recoating device using a die as shown in FIG. 3, as shown in FIGS. 5 and 6, it is also possible to carry out the device using a pair of molds.
[0042]
That is, as shown in FIG. 5 , the fusion-bonded optical fiber core wire 31 is set in the groove portion 34 of one mold 33 and the other mold (not shown) having the same shape is attached. Then, re-coating is performed by filling the mold with the ultraviolet resin 32 and curing it.
[0043]
【The invention's effect】
As described above in detail, according to the present invention, before re-coating the ultraviolet curable resin, the ultraviolet curable resin is spotted in advance when the bare fiber is peeled off. During re-coating, bubbles are effectively prevented from remaining when stripping bare fibers. In particular, it is possible to reliably prevent bubbles from remaining when stripping the bare fiber by irradiating the ultraviolet curable resin with ultraviolet rays after curing, and then performing a recoating process.
[0044]
As a result, the expansion and contraction of bubbles when the temperature changes causes an excessive stress to be applied to the optical fiber, thereby reliably preventing the fiber from being broken and transmission loss from being increased.
[Brief description of the drawings]
FIG. 1 shows a procedure of a fusion splicing method according to one embodiment of the present invention.
FIG. 2 is a diagram showing a procedure of a fusion splicing method according to an embodiment of the present invention.
FIG. 3 is a view showing a normal recoat apparatus.
FIG. 4 is a diagram for explaining a re-covering operation.
FIG. 5 is a view showing another recoat apparatus.
FIG. 6 is a view showing another recoat apparatus.
[Explanation of symbols]
1, 11a, 11b, 23, 31 ... optical fiber core wires 2, 12, 24 ... coating 3, 13a, 13b ... bare fiber 4 ... droplets 4a, 4b of ultraviolet curable resin .... Cured spot UV curable resin 5, 32 ... UV curable resin 14 ... Cutting position 15 ... Cleaved cutting surfaces 16a, 16b ... Movable members 17a, 17b ... Fiber retainer 18a , 18b... Electrode rod 21 ... Die table 22, 22a, 22b ... Recoat die 25 ... Tapered groove 26 ... UV light guide 33 ... Mold 34 ... Groove

Claims (2)

Removing the coating of the fusion splice a pair of optical fibers to be connected, the cover is arranged opposite the ends of the bare fibers removed fused connection, which is the fusion-spliced bare An optical fiber fusion splicing method for recoating on a fiber ,
The fusion spliced connection portion is completely stripped of the coating corresponding to the portion to be recoated to form a bare bare fiber portion,
A droplet of the first UV curable resin having a low viscosity is attached to the vicinity of the boundary between the bare fiber portion of the optical fiber core and the coating portion at one end thereof, and cured by irradiating with UV rays. After letting
Similarly, in the vicinity of the boundary portion between the bare fiber portion and the covering portion at the other end, a droplet of the first ultraviolet curable resin having a low viscosity is attached by hanging, and cured by irradiating with ultraviolet rays,
Thereafter, the second ultraviolet curable resin is recoated, and the fusion splicing method of the optical fiber is characterized. The optical fiber fusion splicing method according to claim 1, wherein the first ultraviolet curable resin and the second ultraviolet curable resin are made of the same material.

Images