JP2001194538A - Optical fiber bundle and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber bundle that is stable in transmission characteristics. SOLUTION: The optical fiber bundle is composed of at least one or more optical fibers 2 held in a bundle and each optical fiber 2 has a core 3a and a clad 3b made of quartz-based glass, and has a resin-made coating layer 4 around the clad 3b are held a bundle, and the coating layers 4 of the adjacent optical fibers 2 are combined with each other when forming the bundle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a chromatic dispersion compensator,
The present invention relates to an optical fiber bundle used for a mode dispersion compensator, an optical amplifier, and the like, and a method for manufacturing the same.

[0002]

2. Description of the Related Art As an optical fiber bundle used for an optical amplifier, a chromatic dispersion compensator, a mode dispersion compensator, and the like, and a method for manufacturing the same, those described in Japanese Patent Application Laid-Open No. 10-123342 are known. The optical fiber bundle exerts a desired action on an optical signal on its optical path. For example, optical fiber bundles used in optical amplifiers are doped with erbium
A coil of EDF (Erbium Doped optical-Fiber) that amplifies an optical signal on the optical path of an optical fiber.

Here, in order to amplify light, an EDF of a certain length is required. However, in order to efficiently store the EDF inside the optical amplifier, it is preferable to form the EDF into a bundle (coil). For this reason, an optical fiber bundle in which the optical fibers are formed into a bundle (coil) is used. The same applies to an optical fiber bundle used for other optical components such as a chromatic dispersion compensator, a mode dispersion compensator, and an optical gyro other than the optical amplifier. Conventional optical fiber bundles are generally configured by winding an optical fiber around a bobbin.

[0004]

However, tension remains in the wound optical fiber, which causes microbend loss. Further, due to the difference in linear expansion coefficient between the bobbin and the optical fiber, a stress is applied to the optical fiber due to the bobbin deformation, so that the transmission loss changes depending on the temperature.

[0005] In view of the above, various contrivances such as those described in the above-mentioned publications have been made to study a bobbin-less optical fiber bundle and a bobbin structure that can provide the same effect as the bundle. However, there are concerns that transmission characteristics may change due to winding collapse due to vibration, kink or disconnection of the optical fiber, and micro-bend loss due to folding of the optical fiber.

Therefore, as shown in the sectional view of the optical fiber bundle in FIG. 5, it has been studied to solidify the entire optical fiber bundle with resin. As shown in FIG. 5, the optical fiber 20 constituting the optical fiber bundle is held in a bundle state by a surrounding resin 21. However, expansion and contraction due to a change in temperature of the resin 21 itself and expansion and contraction due to a change in temperature of the bubble 22 trapped in the resin (such as expansion of the bubble when the temperature rises) may cause microbending in the optical fiber 20. I am concerned. In addition, resin 21
Is not uniform as a whole, the uneven lateral pressure is applied to the optical fiber 20, which causes microbend loss. Even if you select a resin that is unlikely to cause these problems,
In some cases, it is difficult to sufficiently suppress bubbles and non-uniformity in the resin, and further improvement has been desired.

Accordingly, it is an object of the present invention to provide an optical fiber bundle having stable transmission characteristics and a method for manufacturing the optical fiber bundle.

[0008]

According to a first aspect of the present invention, in the optical fiber bundle, the core and the clad are made of silica glass,
At least one optical fiber having a coating layer made of resin around the clad is configured to be held in a bundle state, and the coating layers of adjacent optical fibers are coupled to each other in the bundle state. .

According to a second aspect of the present invention, in the first aspect of the present invention, the coating layers of adjacent optical fibers are fused or welded in contact with each other in a bundle state. .

According to a third aspect of the present invention, in the first aspect of the present invention, the coating layer has an adhesive substance in an outermost layer portion thereof, and the coating layers of the optical fibers adjacent to each other in a bundle state. Are bonded to each other by an adhesive.

According to a fourth aspect of the present invention, in the first aspect, the outermost layer of the coating layer is any one of an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, and a solvent-soluble resin. It is characterized by:

According to a fifth aspect of the present invention, in the method of manufacturing an optical fiber bundle, the core and the clad are made of quartz glass,
A method of manufacturing an optical fiber bundle holding an optical fiber having a coating layer made of a resin around the bundle, a coiling step of bundling at least one optical fiber,
And a holding step of holding the bundle state by coupling the coating layers of the adjacent optical fibers in a contact state in the bundle state.

According to a sixth aspect of the present invention, in the invention of the fifth aspect, the outermost layer of the coating layer is set to a semi-cured state in a step before the coiling step, and the outermost layer of the coating layer is set in the holding step. It is characterized by a hardening treatment.

[0014] The invention according to claim 7 is the invention according to claim 5 or 6.
In the invention described in (1), a vibration step of applying vibration to the bundle of optical fibers is provided between the coiling step and the holding processing step.

An eighth aspect of the present invention provides a polarization mode dispersion compensator having the optical fiber bundle according to the first aspect as a polarization mode dispersion compensator.

A chromatic dispersion compensator according to a ninth aspect has the optical fiber bundle according to the first aspect as a chromatic dispersion compensator.

The optical amplifier according to claim 10 is the first embodiment.
Wherein the optical fiber bundle described in (1) is provided as an optical amplifier.

An optical transmission system according to an eleventh aspect includes an optical component having the optical fiber bundle according to the first aspect.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical fiber bundle and a method for manufacturing the same according to the present invention will be described with reference to the drawings.

As shown in FIG. 1, an optical fiber bundle 1 according to the present embodiment is obtained by forming an optical fiber 2 into a bundle (coil) and maintaining the state. The winding amount of the optical fiber in the coiled portion varies depending on the intended optical component, but may be several tens km. The optical fiber 2 has a glass part 3 made of quartz glass, and two resin coating layers 4 formed around the glass part 3. The center of the glass part 3 is a core 3a, and a clad 3b is formed around the core 3a.
Are formed. The optical fiber 2 of the present invention may be a single-mode fiber or a multi-mode fiber, or may be a step-index fiber or a graded-index fiber. It is not limited to a specific one.

In the present embodiment, the coating layer 4 has an inner layer 4a.
And the outermost layer 4b. The outermost layers 4b are fused or welded to each other. The term “fusion” or “welding” as used herein refers to a state in which the resin constituting the outermost layer 4b is integrated with the resin itself of the other outermost layer 4b in contact. FIG. 2 shows a cross section of the pair of optical fibers 2, and shows only a fused (welded) state of the cross section of the pair of optical fibers 2. However, needless to say, in the coiled optical fiber 2, most of the outermost layers in contact with each other are fused (welded) to each other as shown in FIG. FIG. 3 shows a plurality of optical fibers 2 in such a state.

The coating layer 4 of the present invention may be formed of a plurality of layers or a single layer. If the outermost resin coating layers are fused or welded together, It may be a layer. Further, the outermost layers 4b may be fused or welded to each other by any means. Hereinafter, a specific example will be briefly described. However, the manufacturing method of each specific example will be described later in detail.

First, there may be a case where the outermost layer 4b is made of an ultraviolet curable resin. In this case, at the time of manufacturing the optical fiber 2, the ultraviolet curable resin of the outermost layer 4b is kept in a semi-cured state, the optical fiber 2 is bundled (coiled), and then irradiated with ultraviolet light again to form the outermost layer 4b. May be fused. Thereby, it is possible to form the optical fiber bundle 1 holding the coil shape.

Alternatively, the outermost layer 4b may be made of a thermosetting resin. Also in this case, at the time of manufacturing the optical fiber 2, the thermosetting resin of the outermost layer 4b is kept in a semi-cured state, and after the optical fiber 2 is formed into a coil shape, heat treatment is performed again to fuse the outermost layers 4b together. I just need. Thereby, it is possible to form the optical fiber bundle 1 holding the coil shape.

Alternatively, the outermost layer 4b may be made of a thermoplastic resin. In this case, heat treatment may be performed after the optical fiber 2 is formed into a coil shape, and the outermost layers 4b may be fused together. Thereby, it is possible to form the optical fiber bundle 1 holding the coil shape.

It is also conceivable that the outermost layer 4b is made of a solvent-soluble resin. In this case, the outermost layer 4b may be welded by immersing the coiled optical fiber 2 in a solvent, once dissolving the outermost layer 4b, removing the outermost layer 4b from the solvent, and removing the attached solvent. If the solvent is volatile, it can be removed by standing, or the solvent may be heated to evaporate. by this,
It is possible to form the optical fiber bundle 1 holding the coil-shaped form.

If the outermost layer 4b is formed of any of the above-described resins, the optical fiber bundle 1 in which the outermost layers 4b are fused (welded) in a contact state as described above can be easily manufactured. . Then, the outermost layer 4b as described above
Optical fiber bundles that are fused (welded) in contact with each other
The bundle (coil) state is maintained without being wound around the bobbin or the like. Therefore, the optical fiber 2 hardly generates microbends and has stable optical characteristics. In addition, the outermost layers 4b are fused (welded) in contact with each other without being wound around a bobbin or the like.
In this state, the temperature characteristics are excellent.

Next, an embodiment of a method of manufacturing the above-described optical fiber bundle 1 will be described in detail.

(Embodiment 1) Two layers of DCF (wavelength dispersion compensating optical fiber) were coated with an ultraviolet curing resin. At this time, with respect to the outermost coating layer, the amount of ultraviolet irradiation was set to a small value, and the degree of curing of the ultraviolet curable resin was set to a semi-cured state with a gel fraction of 85%. The gel fraction is an index indicating the degree of curing, and the measuring method will be described below. Sample (DCF) 4
Put m in a bundle or strip and cover it with aluminum and put it in a bottle. At this time, the weight of sample + aluminum + bottle (weight A)
Is measured. Put MEK () as a solvent in the bottle, and add 60
Dissolve the coating at 16 ° C. × 16 hours, then leave in vacuum at 100 ° C. × 2 hours to completely volatilize MEK. Then, the weight (weight B) of the remaining material is measured, and the ratio of the ultraviolet curable resin dissolved in the solvent is calculated. The results are expressed as (100 × weight B / weight A)%.

The ultraviolet curable resin used here has not only the property of being cured by irradiation with ultraviolet rays but also the property of a thermosetting resin which is cured by applying heat. It is also a thermosetting resin. Further, DCF (Dispersion Compensating Fiber) is an optical fiber having a wavelength dispersion characteristic of an opposite sign to a transmission optical fiber such as SMF (Single Mode Fiber), and has a characteristic of canceling chromatic dispersion of a transmission line. I have.

The optical fiber was wound around a mandrel having a diameter of 60 mm to form a bundle (coil), and the mandrel was pulled out to form a DCF bundle [coiling step]. The bundle was vibrated to reduce microbends (vibration step). As mentioned above, the optical fiber using the mandrel
(DCF) was bundled, but since the mandrel is pulled out,
The tension on the optical fiber is released, and the microbend is eliminated. Here, the remaining microbends are further eliminated by applying vibration to the optical fiber in a bundle (coil) state.

The bundle of optical fibers in the bundle (coil) state after the vibration is applied is covered with a wrap, heated at 200 ° C. for 30 minutes, cooled, and then subjected to a hardening treatment of hardening the outermost layer of the resin coating. (Coil) state can be held [holding process step]. A pigtail with an optical connector was attached to the optical fiber bundle manufactured in this manner, so that optical characteristics could be measured. The conventional optical fiber bundle wound around the bobbin and the optical fiber bundle of the present embodiment were subjected to a high-low temperature storage test. The results are shown in [Table 1].

The conventional product is obtained by winding an optical fiber having the same configuration as the product of the present embodiment in the material and thickness of the resin coating layer around a bobbin having a diameter of 60 mm. The outline of the high-low temperature test is described below. A modular optical fiber bundle with pigtails attached to both ends is placed in a thermostatic layer. After changing the temperature at a rate of 1 ° C / min, the measurement temperature (here, measurement was performed at normal temperature (25 ° C), 50 ° C, and 0 ° C) was maintained. After maintaining the same temperature for 1 hour or more, the measurement was performed while maintaining the temperature.

As a measuring method, a light source [using an EE-LED (high-band light source)] and an optical spectrum analyzer are directly connected by a cable with connectors at both ends, and the wavelength dependence of optical power is measured (Pin). Next, a light source-modulated optical fiber bundle-optical spectrum analyzer is connected using a cord with connectors at both ends, and the wavelength dependence of optical power is measured in the same manner (Pout). From the pin-out, the wavelength dependence of the loss of the modularized optical fiber bundle is derived. Shown in the table are the loss measurement results for each wavelength at each measurement temperature.

[0035]

[Table 1] As can be seen from Table 1, the loss of the optical fiber bundle manufactured by the manufacturing method of this embodiment is smaller than that of the conventional product wound on the bobbin. It can also be seen that the wavelength shows a more stable characteristic on the long wavelength side than 1550 nm.

(Embodiment 2) Two layers of DCF (wavelength dispersion compensating optical fiber) were coated with an ultraviolet curing resin. Further, a coating layer was further formed on the second resin coating by using the same ultraviolet curable resin as the second resin. At this time, with respect to the outermost coating layer, the amount of ultraviolet irradiation was set to a small value, and the degree of curing of the ultraviolet curable resin was set to 70% in gel fraction.
% Semi-cured state. The surface of the outermost layer is sticky.

This optical fiber was wound around a mandrel having a diameter of 60 mm to form a bundle (coil), and the mandrel was pulled out to form a DCF bundle [coiling step]. The bundle was vibrated to reduce microbends (vibration step). Pulling out the mandrel releases the tension on the optical fiber to eliminate the microbend, and further applies vibration to the bundle of optical fibers to eliminate the remaining microbend. Same as 1.

Since the outermost layer of the optical fiber in a bundle (coil) state after vibration is in a semi-cured state, the outermost layers in contact with each other are integrated in a semi-cured state. I have. The entire optical fiber in this state was irradiated with ultraviolet rays at 500 mJ / cm ² to carry out a curing treatment for further curing the outermost layer, so that the bundle (coil) state could be retained [retention treatment step]. As in the first embodiment, a pigtail with an optical connector was attached to the manufactured optical fiber bundle so that optical characteristics could be measured.
The conventional optical fiber bundle wound around the bobbin and the optical fiber bundle of the present embodiment were subjected to a high-low temperature storage test. The results are shown in [Table 2].

The conventional product is obtained by winding an optical fiber having the same configuration as that of the product of the present embodiment in the material and thickness of the resin coating layer around a bobbin having a diameter of 60 mm. The conditions of the high / low temperature storage test are the same as those in the first embodiment.

[0040]

[Table 2] As can be seen from Table 2, the loss of the optical fiber bundle manufactured by the manufacturing method of the present embodiment is smaller than that of the conventional product wound on the bobbin. It can also be seen that the wavelength shows a more stable characteristic on the long wavelength side than 1550 nm.

(Embodiment 3) Two layers of DCF (wavelength dispersion compensating optical fiber) were coated with an ultraviolet curing resin. Further, on the second resin coating, another coating layer was formed by extrusion coating using a vinyl chloride resin as a thermoplastic resin. By coating the outermost layer with vinyl chloride resin, the outer diameter of the optical fiber became 0.3 mm.

This optical fiber was wound around a mandrel having a diameter of 60 mm to form a bundle (coil), and the mandrel was pulled out to form a DCF bundle [coiling step]. The bundle was vibrated to reduce microbends (vibration step). Pulling out the mandrel releases the tension on the optical fiber to eliminate the microbend, and further applies vibration to the bundle of optical fibers to eliminate the remaining microbend. Same as 1 and 2.

The optical fiber in a bundle (coil) state after the vibration was applied was heated at 150 ° C. for 30 minutes to once melt the outermost vinyl chloride resin layer to integrate the outermost layers in contact with each other. Then, it cooled and the outermost layer was hardened. By performing the hardening process for hardening the outermost layer in this manner, the bundle (coil) state can be maintained [holding process step]. As in Embodiments 1 and 2, a pigtail with an optical connector was attached to the manufactured optical fiber bundle, so that optical characteristics could be measured. The conventional optical fiber bundle wound around the bobbin and the optical fiber bundle of the present embodiment were subjected to a high-low temperature storage test. The results are shown in [Table 3].

The conventional product is obtained by winding an optical fiber having the same configuration as the product of the present embodiment in the material and thickness of the resin coating layer around a bobbin having a diameter of 60 mm. The conditions of the high / low temperature standing test are the same as those in the first and second embodiments.

[0045]

[Table 3] As can be seen from Table 3, the loss of the optical fiber bundle manufactured by the manufacturing method of the present embodiment is smaller than that of the conventional product wound on the bobbin.

(Embodiment 4) 5 km of a DCF (wavelength dispersion compensating optical fiber) having a resin coating layer of an ultraviolet curable resin is wound around a mandrel having a diameter of 60 mm to form a bundle (coil).
A DCF bundle was formed by pulling out the mandrel [coiling step]. The bundle was vibrated to reduce microbends (vibration step). Pulling out the mandrel releases the tension on the optical fiber to eliminate the microbend, and further applies vibration to the bundle of optical fibers to eliminate the remaining microbend. Same as 1-3.

The bundle of optical fibers after application of the vibration is immersed in a 1% aqueous solution of poval (polyvinyl alcohol) for several seconds to temporarily dissolve the outermost ultraviolet curable resin layer and to contact the outermost layers. Are integrated. Then, the optical fiber in a bundle (coil) state is taken out of the aqueous solution to cut off the excess aqueous solution, and then dried in a thermostat at 90 ° C. to completely remove the excess aqueous solution and remove the integrated outermost layer. Was cured. That is, here, the property of the ultraviolet curable resin of the outermost layer as a solvent-soluble resin that is dissolved by poval (polyvinyl alcohol) as a solvent is used.

The bundle (coil) state can be held by performing the hardening treatment for hardening the outermost layer as described above (holding processing step). As in the first to third embodiments, a pigtail with an optical connector was attached to the manufactured optical fiber bundle so that optical characteristics could be measured. The conventional optical fiber bundle wound around the bobbin and the optical fiber bundle of the present embodiment were subjected to a high-low temperature storage test. The results are shown in [Table 4].

The conventional product is obtained by winding an optical fiber having the same configuration as the product of the present embodiment in the material and thickness of the resin coating layer around a bobbin having a diameter of 60 mm. The conditions of the high-low temperature test are the same as those in the first to third embodiments.

[0050]

[Table 4] As can be seen from Table 4, the loss of the optical fiber bundle manufactured by the manufacturing method of the present embodiment is smaller than that of the conventional product wound on the bobbin.

In the optical fiber bundle in the above-described embodiment, the coating layers of the adjacent optical fibers 2 are bonded by fusion or adhesion. In the embodiment described below, a case where the coating layers of adjacent optical fibers are bonded to each other by bonding using an adhesive substance, instead of bonding by fusion or welding, will be described. FIG. 4 shows a diagram corresponding to FIG. 3 in this case.

In this embodiment, as shown in FIG. 4, the coating layer 4 is composed of a normal resin coating layer 4c and an adhesive layer 4d formed outside the resin coating layer 4c. The resin coating layer 4c may be composed of a plurality of layers. Then, the adhesive layers 4d are bonded to each other by an adhesive force, and the coating layers 4 of the adjacent optical fibers 2 are bonded to each other in the bundle state. In the present embodiment, the adhesive layer 4d is formed over the entire circumference of the resin coating layer 4c, but may be formed so as to be formed only on a part thereof. Even with the optical fiber bundle formed in this way, the above-described fusion
The same effect as that obtained by bonding the coating layers by welding can be obtained.

When manufacturing such an optical fiber coil, an adhesive is applied to the periphery of the resin coating layer 4c of the optical fiber 2 manufactured as usual by using a brush or the like to form an adhesive layer 4d. The adhesive layer 4d is formed on the surface of the optical fiber 2 by, for example, spraying an adhesive on the optical fiber 2 immediately before forming the coil bundle. The adhesive layer 4d may be formed by inserting an optical fiber into a die to which an adhesive is applied. As an adhesive substance for forming the adhesive layer 4d, a vinyl chloride resin or an ultraviolet curable resin can be used.

Next, an embodiment of such a manufacturing method will be described in detail.

(Embodiment 5) Having a normal resin coating layer
5 km of DCF was wound around a mandrel having an outer diameter of 60 mm using an optical fiber rewinding machine. Immediately before winding on the mandrel, place a brush containing UV-curable resin on the pass line of the rewinding machine so that it touches the upper half of the optical fiber surface. Was applied to a part of the surface of the optical fiber. Here, this ultraviolet curable resin is used as an adhesive substance.

After rewinding the optical fiber to the mandrel,
The mandrel was pulled out to bring the optical fiber into a coil bundle. The bundle was vibrated to reduce microbends, and then the entire bundle of optical fibers was irradiated with ultraviolet rays at 500 mJ / cm ² to cure the applied ultraviolet-curable resin and maintain the bundle. A pigtail optical fiber with a connector was attached to both ends of the optical fiber bundle manufactured as described above, and the optical fiber bundle was assembled so that optical characteristics could be measured.

By forming the adhesive layer on the outermost layer as described above, the bundle (coil) state can be maintained [retention processing step]. As in the first to fourth embodiments, a pigtail with an optical connector was attached to the manufactured optical fiber bundle, so that optical characteristics could be measured. The conventional optical fiber bundle wound around the bobbin and the optical fiber bundle of the present embodiment were subjected to a high-low temperature storage test. The results are shown in [Table 5].

The conventional product is obtained by winding an optical fiber having the same configuration as the product of the present embodiment in the material and thickness of the resin coating layer around a bobbin having a diameter of 60 mm. The conditions of the high-low temperature test are the same as those in the first to fourth embodiments.

[0059]

[Table 5] As can be seen from Table 5, the loss of the optical fiber bundle manufactured by the manufacturing method of the present embodiment is smaller than that of the conventional product wound on the bobbin.

(Embodiment 6) Having a normal resin coating layer
5 km of DCF was wound around a mandrel having an outer diameter of 60 mm using an optical fiber rewinding machine. Immediately before winding on the mandrel, dies having four-point holes were placed on the pass line of the rewinding machine every 90 degrees as viewed from the cross section of the optical fiber. The vinyl chloride resin was extruded from the hole of the die onto the outer surface of the optical fiber, and rewinding was performed while applying the vinyl chloride resin to four points as viewed from the cross section of the optical fiber. Here, this vinyl chloride resin is used as an adhesive substance.

After rewinding the optical fiber to the mandrel,
The mandrel was pulled out to bring the optical fiber into a coil bundle. After reducing the microbend by vibrating the bundle, the bundle of optical fibers is heat-treated at 150 ° C for 30 minutes,
The vinyl chloride resin was cured, and the bundle was maintained. A pigtail optical fiber with a connector was attached to both ends of the optical fiber bundle manufactured as described above, and the optical fiber bundle was assembled so that optical characteristics could be measured.

By forming the adhesive layer on the outermost layer as described above, the bundle (coil) state can be maintained [retention processing step]. As in Embodiments 1 to 5, a pigtail with an optical connector was attached to the manufactured optical fiber bundle, so that optical characteristics could be measured. The conventional optical fiber bundle wound around the bobbin and the optical fiber bundle of the present embodiment were subjected to a high-low temperature storage test. The results are shown in [Table 6].

The conventional product is obtained by winding an optical fiber having the same configuration as that of the product of the present embodiment in the material and thickness of the resin coating layer around a bobbin having a diameter of 60 mm. The conditions of the high-low temperature test are the same as those in the first to fifth embodiments.

[0064]

[Table 6] As can be seen from Table 6, the loss of the optical fiber bundle manufactured by the manufacturing method of the present embodiment is smaller than that of the conventional product wound on the bobbin.

(Embodiment 7) Having a normal resin coating layer
5 km of DCF was wound around a mandrel having an outer diameter of 60 mm using an optical fiber rewinding machine. Immediately before winding on the mandrel, a spray device that sprays UV curable resin is installed on the pass line of the rewinding machine, and sprays UV curable resin onto the surface of the optical fiber while rewinding the optical fiber to apply it. did. Here, this ultraviolet curable resin is used as an adhesive substance.

After the optical fiber is wound around the mandrel,
The mandrel was pulled out to bring the optical fiber into a coil bundle. The bundle was vibrated to reduce microbends, and then the entire bundle of optical fibers was irradiated with ultraviolet rays at 500 mJ / cm ² to cure the applied ultraviolet-curable resin and maintain the bundle. A pigtail optical fiber with a connector was attached to both ends of the optical fiber bundle manufactured as described above, and the optical fiber bundle was assembled so that optical characteristics could be measured.

By forming the adhesive layer on the outermost layer as described above, the bundle (coil) state can be maintained [retention processing step]. As in Embodiments 1 to 5, a pigtail with an optical connector was attached to the manufactured optical fiber bundle, so that optical characteristics could be measured. The conventional optical fiber bundle wound around the bobbin and the optical fiber bundle of the present embodiment were subjected to a high-low temperature storage test. The results are shown in [Table 7].

The conventional product is obtained by winding an optical fiber having exactly the same configuration as the product of the present embodiment in the material and thickness of the resin coating layer around a bobbin having a diameter of 60 mm. The conditions of the high-low temperature test are the same as those in the first to sixth embodiments.

[0069]

[Table 7] As can be seen from Table 7, the loss of the optical fiber bundle manufactured by the manufacturing method of the present embodiment is smaller than that of the conventional product wound around the bobbin.

As described above, in the case of the optical fiber coil in which the covering layers 4 are positively connected to each other and the bundle state is maintained, there is no influence of the bubbles 22 as shown in FIG. Certainly, a closed space may be formed by joining the coating layers in a bundle state. However, it is extremely rare that a completely different space is formed by the overlapping optical fibers, and according to the above-described embodiment, the side pressure of the optical fiber is increased due to the thermal expansion and contraction of the gas in the closed space (bubble). It can be said that there is hardly any receiving.

In the case shown in FIG. 5, the optical fiber 20 is buried in a viscous resin, so that a large number of bubbles 22 are likely to be mixed in the resin. Since the coating layers 4 are bonded to each other, almost no closed space such as a bubble is formed. Here, the formed closed space (bubble) with respect to the volume of the optical fiber bundle
Is defined as the closed space formation rate, in the case as shown in FIG. 5, the closed space formation rate may be as high as 20%. In the case shown in FIG. 5 as well, if the manufacturing method is devised, the closed space formation rate can be further reduced, but the number of steps increases, and it becomes necessary to prepare a new device. On the other hand, if the covering layer 4 itself is bonded as described above, the closed space formation rate can be easily reduced to 1% or less.

The above-described optical fiber bundle is manufactured using a DCF (wavelength dispersion compensating optical fiber), and is intended to be incorporated in a chromatic dispersion compensator (DCFM: Dispersion Compensation Fiber Module). But,
The application of the optical fiber bundle of the present invention is not limited to this.

For example, by using an EDF (Erbium Doped Fiber) as an optical fiber constituting an optical fiber bundle, the optical fiber bundle can be incorporated into an optical amplifier (EDFA: Erbium Doped Fiber Amplifier) to perform optical amplification. You can also. EDF (Erbium Doped Fiber) is an optical fiber with erbium ions added to the core.It absorbs light of a specific wavelength (0.98 μm, 1.48 μm) while signal light of another specific wavelength (1.55 μm) band. Is incident, stimulated emission is caused to amplify the power of the signal light.
Usually, it is used in a module form.

Further, PMF (Polarization Maintaining Fib)
er), an optical fiber bundle intended to be incorporated in a polarization mode dispersion compensator or an optical gyro can be obtained. PMF (Polarization Maintaining Fib
er) transmits an optical signal while maintaining linear polarization, and is used as a fiber for polarization dispersion compensation or as an optical gyro as described above. Usually a module (PMFM: Polarization Maintaining Fiber Mod
ule).

An example in which the above-described optical fiber bundle is applied to the above-described optical devices and an example of a transmission system to which these devices are applied will be briefly described below.

FIG. 6 shows a DCFM (wavelength dispersion compensator) using an optical fiber bundle constituted by the above-described DCF. As shown in FIG. 6, the DCFM has a DCF bundle 1 which is an optical fiber bundle in a housing 5. At both ends of the coiled optical fiber of the DCF bundle 1, a fused portion 6 is provided.
Pigtail fiber 8 with optical connector 7 via
Is attached. The optical connector 7 is led out of the housing 5 to facilitate the incorporation of the DCFM into an optical transmission system.

FIG. 7 shows an EDFA (optical amplifier) using an optical fiber bundle composed of EDFs. As shown in FIG. 7, the EDFA has an EDF bundle 1 that is an optical fiber bundle. At both ends of the coiled optical fiber of the EDF bundle 1, WDM couplers 9 are respectively attached. Two optical fibers are led out of each WDM coupler 9, one of which is an optical fiber for transmitting a main signal, and the other is an excitation light source 10.
Is an optical fiber for transmitting light from the EDF bundle 1 to the EDF bundle 1. An isolator 11 is attached between the WDM coupler 9 and the excitation light source 10 so that only light having a specific wavelength for excitation is transmitted to the EDF bundle 1.

FIG. 8 shows a PMFM (Polarization Mode Dispersion Compensator) using an optical fiber bundle constituted by a PMF. As shown in FIG. 8, the PMFM has a plurality of sets of PMF bundles 1 as optical fiber bundles inside a housing 5. These PMF bundles 1 have different amounts of polarization dispersion. Optical switches 12 are arranged on both sides of the plurality of PMF bundles 1, and optical fibers for inputting and outputting optical signals are attached to the outside of the housing 5 from the optical switches 12. With the above-described configuration, desired polarization mode dispersion compensation can be performed by switching the optical switch 12 and selecting the PMF bundle 1 having a desired polarization dispersion amount.

As described above, since the optical fiber bundle of the present invention has stable transmission characteristics, the chromatic dispersion compensator, optical amplifier, and polarization mode dispersion compensator as shown in FIGS. It has transmission characteristics.

FIG. 9 shows the optical fiber bundle of the present invention described above.
1 shows an optical transmission system incorporated as DCFM and EDFA. In the optical transmission system, the optical signal transmitted by the optical transmitter 13 is received by the optical receiver 14, but the optical signal is
Chromatic dispersion occurs on the transmission line. Also, the longer the transmission distance of the optical transmission system, the greater the transmission loss and the weaker the optical signal. Therefore, the chromatic dispersion compensation is performed by the DCFM 15 described above, and the optical signal weakened by the EDFA 16 is amplified.

FIG. 10 shows another example of an optical transmission system incorporating the optical fiber bundle of the present invention. This system is different from the system shown in FIG. 9 in that the configuration for compensating the polarization mode dispersion is provided. It has been added. Here, the optical fiber bundle of the present invention is also incorporated in the optical system as the above-mentioned PMFM. In this system, the signal analyzer 17a is installed on the optical transmission line,
A signal analyzer 17b is incorporated downstream of the FA 16. This pair of signal analyzers 17a, 1
The comparison and control circuit 18 compares the input side waveform and the output side waveform of the optical signal detected by 7b to measure the amount of polarization dispersion. Then, the PMFM 19 is controlled by the comparison / control circuit 18 based on the measured amount of polarization dispersion to compensate for the polarization mode dispersion.

As described above, the optical fiber bundle of the present invention has stable transmission characteristics. For this reason, various optical components (DCFM: chromatic dispersion compensator, E
DFM: optical amplifier, PMFM: polarization mode dispersion compensator, etc.) into the optical transmission system as described above,
The entire optical transmission system has excellent transmission characteristics.

The present invention is not limited to the embodiment described above. For example, for an optical fiber bundle,
It is sufficient that at least the resin coating layers are fused or welded, and not only the outermost layer but also further inner layers may be fused or welded (or not). Further, the use of the optical fiber bundle according to the first or second aspect or the optical fiber bundle manufactured by the manufacturing method according to the third to fifth aspects is not limited to the above-described embodiment. Any optical fiber bundle may be used as long as the optical fiber is formed into a bundle (coil).

[0084]

According to the optical fiber bundle of the present invention, since the coating layers of the optical fibers constituting the optical fiber bundle are connected to each other, unnecessary side pressure is applied to the optical fibers constituting the optical fiber bundle. And the bundle (coil) state is maintained without causing microbending. For this reason, the optical fiber bundle of the present invention has stable and excellent transmission characteristics.

Here, when the coating layers are bonded to each other by fusing or welding the coating layers and bonding the coating layers together, it is easy to form the optical fiber bundle and to surely maintain the bundle state. be able to. In addition, by bonding the coating layers to each other by forming an adhesive layer on the outermost layer to bond the coating layers, it is possible to easily form an optical fiber bundle, and to reliably maintain the bundle state. . Furthermore, by forming the outermost layer of the resin coating layer using any one of an ultraviolet curable resin, a thermosetting resin, and a solvent-soluble resin, an optical fiber bundle can be easily and simply manufactured.

According to the method of manufacturing an optical fiber bundle of the present invention, the outermost layers of the resin coating layers of the optical fibers constituting the optical fiber bundle are joined to each other, so that the optical fibers constituting the manufactured optical fiber bundle are combined. The bundle (coil) state can be maintained in a state in which no unnecessary side pressure is applied to the, and no microbending occurs. Therefore, according to the optical fiber bundle manufacturing method of the present invention, an optical fiber bundle having stable and excellent transmission characteristics can be manufactured.

Here, the outermost layer of the resin coating layer is set in a semi-cured state in a step before coiling, and a curing treatment is performed in a holding processing step to integrate the outermost layers. By manufacturing in this manner, a bundle (coil) state can be reliably maintained without causing microbending in the optical fiber, and an optical fiber bundle having even more excellent transmission characteristics can be manufactured.

Further, by providing a vibration step between the coiling step and the holding processing step, the microbend generated in the bundle of optical fibers in a bundle (coil) state can be further eliminated, and further excellent. An optical fiber bundle having improved transmission characteristics can be manufactured.

According to the inventions set forth in claims 7 to 10, since each of the optical components is constituted by using the optical fiber bundle of the present invention (claim 1), each optical component (polarization mode dispersion compensator, Chromatic dispersion compensators and optical amplifiers) have stable and excellent transmission characteristics. According to the optical transmission system of the eleventh aspect, since the optical component having the optical fiber bundle according to the present invention (the first aspect) is provided, it has stable and excellent transmission characteristics. Becomes

[Brief description of the drawings]

FIG. 1 is a perspective view showing an appearance of an embodiment of an optical fiber bundle according to the present invention.

FIG. 2 is a cross-sectional view showing a state of fusion (fusion) of optical fibers in an optical fiber bundle according to the present invention.

FIG. 3 is a cross-sectional view showing a state of fusion (fusion) of optical fibers in the optical fiber bundle of the present invention.

FIG. 4 is a cross-sectional view showing a state of fusion (adhesion) between optical fibers in the optical fiber bundle of the present invention.

FIG. 5 is a cross-sectional view showing a type of optical fiber bundle in which the periphery of the optical fiber is molded with resin.

FIG. 6 is an explanatory view schematically showing a chromatic dispersion compensator having an optical fiber bundle (DCF bundle) of the present invention.

FIG. 7 is an explanatory view schematically showing an optical amplifier having an optical fiber bundle (EDF bundle) according to the present invention.

FIG. 8 is an explanatory view schematically showing a polarization mode dispersion compensator having an optical fiber bundle (PMF bundle) according to the present invention.

FIG. 9 is an explanatory diagram showing an example of an optical transmission system incorporating an optical component having an optical fiber bundle according to the present invention.

FIG. 10 is an explanatory diagram showing another example of the optical transmission system incorporating the optical component having the optical fiber bundle according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical fiber bundle, 2 ... Optical fiber, 3 ... Glass part, 3
a: core, 3b: clad, 4: resin coating layer, 4b: outermost layer, 4d: adhesive layer, 15: chromatic dispersion compensator (DCFM), 1
6: Optical amplifier (EDFA), 17: Polarization mode dispersion compensator (PMF)
M).

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Fujii 1-term Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa F-term (reference) in Yokohama Works, Sumitomo Electric Industries, Ltd. 2H046 AA02 AC01 AD22 AZ09 5F072 AB09 AK06 JJ05 YY17

Claims (11)

[Claims] 1. An optical fiber bundle comprising a core and a clad made of silica-based glass and holding at least one optical fiber having a coating layer made of a resin around the clad in a bundle state. An optical fiber bundle, wherein the coating layers of the adjacent optical fibers are connected to each other in a state. 2. The optical fiber bundle according to claim 1, wherein the coating layers of the optical fibers adjacent to each other in the bundle state are fused or welded in a contact state. 3. The coating layer has an adhesive substance in an outermost layer portion thereof, and the coating layers of the adjacent optical fibers are bonded to each other by the adhesive substance when bundled. The optical fiber bundle according to claim 1, wherein: 4. The optical fiber bundle according to claim 1, wherein the outermost layer of the coating layer is any one of an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, and a solvent-soluble resin. 5. A method for producing an optical fiber bundle in which an optical fiber having a core and a clad made of silica-based glass and having a coating layer made of resin around the bundle is held in a bundle state, wherein at least one of the optical fibers is Producing an optical fiber bundle, comprising: a coiling step of forming a bundle state; and a holding processing step of holding the bundle state by bonding the coating layers of the adjacent optical fibers in a contact state in the bundle state. Method. 6. The method according to claim 5, wherein the outermost layer of the coating layer is semi-cured in a step before the coiling step, and the outermost layer of the coating layer is cured in the holding processing step. A manufacturing method of the optical fiber bundle according to the above. 7. The optical fiber bundle according to claim 5, further comprising a vibration step of applying vibration to the bundle of optical fibers between the coiling step and the holding processing step. Manufacturing method. 8. A polarization mode dispersion compensator comprising the optical fiber bundle according to claim 1 as a polarization mode dispersion compensator. 9. A chromatic dispersion compensator comprising the optical fiber bundle according to claim 1 as a chromatic dispersion compensator. 10. An optical amplifier comprising the optical fiber bundle according to claim 1 as an optical amplifier. 11. An optical transmission system comprising an optical component having the optical fiber bundle according to claim 1.