JP2001311834A - Optical part and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical part and an method for manufacturing the optical part wherein a micro-bend loss is controlled and transmission characteristics are stable. SOLUTION: In the optical part P, an optical fiber coil 81 is housed in a housing casing 80. The fiber coil 81 is composed by winding an optical fiber 32 in a coil shape and is set in the coil bundle state that the wind distortion is substantially released. A filler 84 is filled in the housing casing 80 in the state that it comes into direct contact with the outer periphery of the optical fiber 32 so as to enclose the optical fiber 32. The filler 84 is made of thermosetting or ultraviolet ray setting silicone resin or the like and consists of a substance in which weight-concentration of a Na+ ion and a K+ ion (ionic impurities of a positive ion) determined by the whole resolving method is 0.1-6 ppm and also weight-concentration of Cl- ion (ionic impurities of a negative ion) determined by the whole resolving method is 0.5-10 ppm.

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 component used for a mode dispersion compensator, an optical amplifier, an optical fiber gyro, and the like, and a method for manufacturing the same.

[0002]

2. Description of the Related Art As an optical component used for an optical amplifier, a chromatic dispersion compensator, a mode dispersion compensator, an optical fiber gyro, and the like, and a method of manufacturing the same, those described in Japanese Patent Application Laid-Open No. 10-123342 are known. ing. The optical fiber coil included in the optical component exerts a desired action on an optical signal on the optical path. For example, an optical fiber coil used in an optical amplifier is formed by coiling an erbium-doped EDF (Erbium Doped optical-Fiber), and amplifies an optical signal on an optical path of the 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 that the EDF be in a coil bundle state. For this reason, an optical fiber coil in which the optical fiber is in a coil bundle state is used. The same applies to optical fiber coils used for other optical components such as chromatic dispersion compensators, mode dispersion compensators, and optical fiber gyros other than optical amplifiers. A conventional optical fiber coil is generally configured by winding an optical fiber around a bobbin.

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. Therefore, various ideas such as those described in the above-mentioned publications have been devised, and a bobbin-less optical fiber coil and a bobbin structure capable of obtaining an equivalent effect have been studied.

[0005]

However, even with these various measures, bending loss (microbend loss) caused by minute bending of the optical fiber cannot be completely removed. The inventors have conducted intensive studies to minimize the microbend loss in the optical fiber coil. As a result, it has been found that triboelectric charging generated when an optical fiber is wound around a bobbin is involved in the generation of microbend loss. When the optical fibers are frictionally charged, an electrostatic attraction is generated between the adjacent optical fibers and the adjacent optical fibers adhere to each other, and the optical fibers receive side pressure in a direction perpendicular to the side of the optical fibers. Become. It is considered that the microbend loss is caused by bending of the optical fiber due to the lateral pressure.

[0006] In order to reduce the triboelectric charge generated when the optical fiber is wound around the bobbin, it is conceivable to provide the optical fiber winding device with an electrostatic removing device. However, even when a static electricity removing device is provided in the fiber winding device, static electricity cannot be completely removed,
It has been newly found that the effect of charging substantially remains.
Further, it has been found that the optical fibers come into contact with each other and are frictionally charged during subsequent use.

[0007] The present invention is based on the above findings,
An object of the present invention is to provide an optical component that suppresses microbend loss and has stable transmission characteristics, and a method for manufacturing the optical component.

[0008]

An optical component according to the present invention comprises an optical fiber coil composed of an optical fiber wound in a coil shape, a storage case for storing the optical fiber coil, and an outer peripheral surface of the optical fiber. In direct contact with
And a filler to be filled in the storage case, wherein the filler is:
The weight concentration of the ionic impurities of the positive ions determined by the total decomposition method is 0.1 to 6 ppm, and the weight concentration of the ionic impurities of the negative ions determined by the total decomposition method is 0.5 to 10 ppm. It is characterized by being a substance.

The optical component according to the present invention includes an optical fiber coil, a storage case, and a filler, and the filler has a weight concentration of positive ion ionic impurities determined by a total decomposition method of 0.1%. 1 to 6 ppm, and since the weight concentration of the ionic impurities of the negative ions determined by the total decomposition method is 0.5 to 10 ppm, in a state where the optical fiber coil is stored in the storage case,
Although the optical fiber and the filler are in contact with each other and are charged with different signs of static electricity, contact between the optical fibers is suppressed,
It is possible to suppress the optical fibers from being charged with different signs of static electricity. As described above, since the optical fibers are prevented from being charged with static electricity having different signs, the electrostatic attraction generated between the adjacent optical fibers is reduced, and the side pressure generated due to the contact between the optical fibers is reduced. can do. As a result, micro-bend loss in the optical fiber coil can be suppressed, and the transmission characteristics can be stabilized. Here, the total decomposition method is
This is a method of quantitatively analyzing the weight concentration of each ion as a 100% composition of all components contained in the sample to be inspected. For example, after decomposing a cured gel with hydrogen fluoride, the residue is analyzed by atomic absorption spectrometry. The weight concentration of each ion is measured using the method described above.

After the filler is left in a 1% aqueous solution of NaCl at 50 ° C. for 240 hours, the weight concentration of Na ⁺ ions determined by the total decomposition method is not more than twice the initial value and 1%.
It is preferable that the substance be a substance having a weight concentration of Cl ⁻ ion of not more than twice the initial value and not more than 10 ppm as determined by the total decomposition method. With this configuration,
It is further suppressed that the optical fibers are charged with static electricity having different signs. As a result, the electrostatic attractive force generated between the adjacent optical fibers becomes extremely small, and the side pressure generated when the optical fibers come into contact with each other can be further reduced.

The filler has a storage consistency specified by JIS K 2220 of 5 or more at a measurement temperature of + 23 ° C.
Preferably, the substance is in the range of 00 or less. As described above, since the filler is a substance having a storage consistency defined by JIS K 2220 of 5 or more at a measurement temperature of + 23 ° C., the optical fiber and the filler come into contact with each other at a general use temperature of an optical component. Even when the optical fiber and the filler are charged with static electricity having different signs from each other and an electrostatic attraction acts between the optical fiber and the filler, the optical fiber can be formed by setting the storage consistency specified in JIS K 2220 to 5 or more. The received side pressure can be kept low, and the long wavelength side loss due to the microbend loss of the optical fiber can be suppressed from increasing. The filler is JIS K 2220
The storage consistency specified in the above is 200 at the measurement temperature + 23 ° C.
By using the following substances, the shape of the optical fiber coil can be reliably maintained, and the optical fiber coil can be prevented from being collapsed during use, thereby further stabilizing the transmission loss. it can.

The filler is preferably a substance having a storage consistency specified by JIS K 2220 of 5 or more at a measurement temperature of −40 ° C. and 200 or less at a measurement temperature of + 100 ° C. As described above, the filler is JIS K
Storage consistency specified in 2220 is measured temperature -40
A substance having a temperature of 5 or more at ℃ and a temperature of 200 or less at a measurement temperature of + 100 ° C. can suppress an increase in long-wavelength loss due to microbend loss of an optical fiber in a practical use temperature range of an optical component. In addition, the transmission loss can be further stabilized.

The filler is preferably a substance having a volume resistivity specified by JIS K 6911 of 2 × 10 ¹⁴ Ω · cm or more at a measurement temperature of -5 to + 50 ° C. As described above, since the filler is a substance having a volume resistivity specified by JIS K 6911 of 2 × 10 ¹⁴ Ω · cm or more in a range of the measurement temperature of −5 to + 50 ° C., particularly, an optical component is dispersion-compensated. When applied as a compensator, in the operating temperature range of the dispersion compensator, the optical fibers are charged with different signs of static electricity and are prevented from being in close contact with each other, and the microbend loss in the optical fiber coil is suppressed. In addition, the transmission characteristics can be stabilized.

The filler is a substance having a volume resistivity defined by JIS K 6911 within a range of 1 × 10 ^{13 to} 5 × 10 ¹⁶ Ω · cm at a measurement temperature of −40 to + 85 ° C. Is preferred. Thus, the filling material is JI
The volume resistivity specified in SK6911 is measured temperature-
1 × 10 ^{13 to} 5 × 10 ¹⁶ Ω · c in the range of 40 to + 85 ° C.
Since the substance is within the range of m, the optical fibers are charged with static electricity having different signs and statically charged in the storage and use temperature range of the dispersion compensator, particularly when the optical component is applied as a dispersion compensator. Electroadhesion is suppressed, micro-bend loss in the optical fiber coil can be suppressed, and transmission characteristics can be stabilized.

[0015] The filler is preferably a substance that generates 0.001 ml / g or less of hydrogen after heat treatment at 60 ° C for 24 hours. Thus, the filler is 60
The amount of hydrogen generated after heat treatment at 24 ° C. for 24 hours is 0.00
When the substance is 1 ml / g or less, it is possible to suppress an increase in loss of the optical fiber due to hydrogen generated from the filler penetrating into the optical fiber, and to obtain an optical component suitable for practical use. it can.

Preferably, the filler contains a hydrogen absorbing substance. As described above, since the filler contains the hydrogen absorbing substance, it is possible to prevent hydrogen from penetrating into the optical fiber and suppress an increase in transmission loss due to hydrogen in the optical fiber.

In the optical fiber, at a wavelength within the wavelength band used, at least one of the chromatic dispersion and the chromatic dispersion slope has the opposite sign to that of the optical fiber for the transmission line connected to the optical fiber coil. It is preferred that Thus, at a wavelength within the wavelength band used, at least one of the chromatic dispersion and the chromatic dispersion slope of the optical fiber has a sign opposite to that of the transmission line optical fiber connected to the optical fiber coil. In some cases, the optical component functions as a dispersion compensator that reduces chromatic dispersion in a predetermined wavelength band. Thereby, a dispersion compensator having good characteristics can be obtained.

Further, it is preferable that the wavelength band used is a wavelength of 1.5 μm or more. As described above, when the wavelength band used is 1.5 μm or more, the optical component functions as a dispersion compensator that reduces chromatic dispersion in the wavelength band of 1.5 μm or more. As a result, a dispersion compensator having good characteristics in a wavelength band of 1.5 μm or more can be obtained.

The optical fiber preferably has a bending loss of 1 dB / m or more when bent to a radius of curvature of 20 mm at a wavelength within the wavelength band used.

The method of manufacturing an optical component according to the present invention comprises the steps of: winding an optical fiber around a central body; removing the wound optical fiber from the central body to form an optical fiber coil; and housing the optical fiber coil. The step of storing in a case, the weight concentration of the ionic impurities of the positive ions determined by the total decomposition method is 0.1 to 6 ppm, and the weight concentration of the ionic impurities of the negative ions determined by the total decomposition method is 0; And filling the filler into the storage case using a filler of 0.5 to 10 ppm.

In the method for manufacturing an optical component according to the present invention, in particular, the weight concentration of the ionic impurities of the positive ions determined by the total decomposition method is 0.1 to 6 ppm, and the negative ions determined by the total decomposition method are particularly used. The method has a step of filling the filler in the storage case using a filler having a weight concentration of the ionic impurity of 0.5 to 10 ppm, so that micro-bend loss in the optical fiber coil can be suppressed. In addition, an optical component capable of stabilizing transmission characteristics can be manufactured.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the optical component of the present invention will be described with reference to the drawings. In the following, in order to facilitate understanding of the description, the same constituent elements will be denoted by the same reference numerals as much as possible in each drawing, and redundant description will be omitted.

FIG. 1 is a sectional view showing an embodiment of an optical component according to the present invention, and FIG. 2 is a plan view showing a state in which a lid 82 is removed. The optical component of this embodiment is a chromatic dispersion compensating optical fiber (Dispersion Compensation optical fiber).
Fiber: DCFM (Disper)
sion Compensation optical-Fiber Module). The DCF is an optical fiber having a wavelength dispersion characteristic of an opposite sign to that of a transmission line optical fiber such as a single mode optical fiber, and is an optical fiber capable of canceling out the chromatic dispersion of the optical transmission line.

As shown in FIGS. 1 and 2, the optical component P of the present embodiment has an optical fiber coil 81 housed in a housing case 80 having a rectangular bottom surface. The optical fiber coil 81 is configured by winding the optical fiber 32 into a coil shape, and is in a coil bundle state in which the winding distortion is substantially released. Both ends of the optical fiber 32 (optical fiber coil 81) are connected to a pigtail fiber 45 by a fusion portion 44. The filling material 84 is filled in the storage case 80 in a state of directly contacting the outer peripheral surface of the optical fiber 32 so as to surround the optical fiber 32. Here, it is preferable that the filler 84 also enters between the optical fibers 32 in the coil bundle state.
Then, a lid 82 is attached to the storage case 80,
Sealed.

Here, the state in which the winding distortion is substantially eliminated means a state in which an increase in transmission loss in a wavelength band of a wavelength of 1.50 μm or more due to winding is reduced by 0.1 dB / km or more. I do. Optical fiber 32 of the present embodiment
Is wound around a bobbin as a central body, then removed from the bobbin and brought into a coil bundle state (optical fiber coil 81). The increase in transmission loss of the optical fiber 32 in a state where the optical fiber 32 is removed from the bobbin and unwound is disclosed in
This is because, as disclosed in JP-A-123342, it is almost eliminated, and if the winding distortion is eliminated, the associated transmission loss is also eliminated.

FIG. 3A is a sectional view of the optical fiber 32, and FIG. 4 is a view showing a refractive index profile thereof. As shown in FIG. 3A, this optical fiber 32
Consists of only a glass part 11 composed of a core and a clad, and a carbon coating is applied on the outer peripheral surface of the clad. The optical fiber 32 is shown in FIG.
The coating layers 13 and 15 are removed from those having two coating layers 13 and 15 formed of two layers of ultraviolet curable resin around the glass portion 11 as shown in FIG.

The glass part 11 has a core diameter a of 2.7 μm.
m, a double-clad DCF having a depressed portion diameter b of 6.6 μm (see FIG. 4) and an outer diameter c of 120 μm.
m, the thickness d of the primary coating layer 13 before coating removal is 15 μm,
The thickness e of the secondary coating layer 15 was also 15 μm, and the outer diameter f of the optical fiber before removing the coating layer was 190 μm. Δ (delta) +, Δ (delta) −, which is the increase or decrease of the refractive index of the core portion and the depressed portion with respect to the refractive index of the cladding portion.
Are 1.9% and -0.4%, respectively. This DC
The chromatic dispersion and the chromatic dispersion slope of F are 1.55 and 1.55 respectively.
-120 ps / nm / km, -0.28 ps / n at μm
m ² / km, and the transmission loss is 0.40 dB / km.

The chromatic dispersion value and the chromatic dispersion inclination value have the opposite signs to those of the transmission line optical fiber connected to the optical component P. That is, by using the optical component P of the present embodiment, chromatic dispersion caused by the optical fiber in the transmission path can be compensated. For wavelength band transmission, chromatic dispersion can be compensated over the wavelength band by setting the chromatic dispersion slope to the opposite sign. In addition, when the wavelength band used of the optical fiber 32 is 1.50 μm or more, the increase in loss due to microbending caused by coating of an acrylate-based ultraviolet curable resin or a silicone resin, which is usually found in optical fibers, is large. Very effective.

The carbon coating layer formed on the outer peripheral surface of the clad is a thin film having a function of improving the strength of the optical fiber 32 or a function of suppressing hydrogen intrusion into the glass portion 11 of the optical fiber 32. As long as it has a function of improving the strength of the optical fiber 32 or a function of suppressing hydrogen intrusion into the glass portion 11 of the optical fiber 32, such a thin film may be formed by a method other than carbon coating.
With this thin film, the growth of microscopic scratches on the surface can be suppressed, the intrusion of hydrogen into the glass portion 11 can be prevented, and the deterioration of the optical fiber 32 can be prevented.

As the filler 84, a thermosetting or ultraviolet curable silicone resin, butadiene,
A high-viscosity jelly-like admixture obtained by swelling a rubber such as silicone with a solvent such as silicone or naphthene and adding other resins or the like as necessary can be used. This filler 84
Means that the storage consistency specified in JIS K 2220 is 5 or more at a measurement temperature of −40 ° C., and a measurement temperature of +1
The material is sufficiently softer (having a lower Young's modulus) than the secondary coating layer 15 of 200 or less at 00 ° C. In particular, JIS
The storage consistency specified in K2220 is the measured temperature +
It is a substance of 5 to 200 at 23 ° C. Note that -40
The temperature range of ° C. to + 100 ° C. is a practical use temperature range of the optical component P, and + 23 ° C. is a general use temperature of the optical component P. The relationship between storage consistency and Young's modulus is
As shown in FIG.

The filler 84 is made of JIS K6
The volume resistivity specified in 911 is measured temperature -5 to +50.
2 × 10 ¹⁴ Ω · cm or more in the range of ° C.
JIS K 691 even in the range of 40 to + 85 ° C.
The volume resistivity specified in 1 is 1 × 10 ^{13 to} 5 × 10 ¹⁶ Ω
-It is a substance in the range of cm. In addition, -5 to +50
° C. is a general operating temperature range of the dispersion compensator when the optical component P is applied as a dispersion compensator, and is −4.
0- + 85 ° C. is also a typical use and storage temperature range for dispersion compensators.

As a factor for lowering the volume resistivity of the filler 84, the filler 84 contains ionic impurities such as positive ions and negative ions, which have relatively large ionization tendency. As the ionic impurities of the positive ions, Na
⁺ Ions and K ⁺ ions are assumed, and Cl ⁻ ions are assumed as negative ion ionic impurities. From the above, the filler 84 has a weight concentration of Na ⁺ ion and K ⁺ ion (positive ionic impurity) of 0.1 to 6 ppm determined by the total decomposition method, and The weight concentration of the quantified Cl ^- ion (ionic impurity of negative ion) is 0.5 to 10 ppm
Is a substance. More specifically, the filler 84 has a weight concentration of Na ⁺ ions of 0.1 to 0.5 ppm, a weight concentration of K ⁺ ions of 0.1 to 5 ppm, and a weight concentration of Cl ⁻ ions of 1 to 1 ppm. 6 ppm.

The optical fiber 32 itself and the storage case 8
It is also conceivable that ionic impurities such as positive ions and negative ions as described above may be released into the filler 84 due to factors such as 0 or an aqueous ionic solution flowing from outside the optical component P. Is that, after standing in a 1% NaCl aqueous solution at 50 ° C. for 240 hours, the weight concentration of Na ⁺ ions determined by the total decomposition method is twice or less and 1 ppm or less of the initial value, and Cl ⁻ ions determined by the total decomposition method Is a substance whose weight concentration is twice or less the initial value and 10 ppm or less.

Here, the total decomposition method is a method of quantitatively analyzing the weight concentration of each ion by setting all components contained in the test sample to 100% composition, and for example, fluorinating the cured gel. After being decomposed with hydrogen, the residue is measured for the weight concentration of each ion using atomic absorption spectrometry or the like. Also, with atomic absorption analysis, the target element is atomized by heat energy such as burner heating or heater heating to create an atomic vapor, and light having a wavelength that excites the atom from the ground state is transmitted to the atomic vapor. Since light absorption occurs according to the number of atomic vapors, it is a method of measuring the weight concentration of each ion based on the absorbance.

This filler 84 has a hydrogen generation amount of 0.001 ml / g or less after a temperature deterioration test at 60 ° C. for 24 hours, and has a refractive index of the cladding (the outermost layer portion of the glass portion 11). Is greater than the rate.

If the filler 84 is adhered to 50% or more of the surface area of the inner wall of the storage case 80, vibration resistance and impact resistance are maintained. Note that the filling material 84 may be completely filled in the storage case 80 and adhered to 100% of the surface area of the inner wall of the storage case 80.

When the optical fiber 32 in the coil bundle state is fixed with an ordinary adhesive or resin, the Young's modulus of the resin at the time of curing reaches 500 N / mm ² or more, so that an excessive pressing force is applied to the optical fiber 32. As a result, a bending strain is generated, which is not preferable. With such flexibility,
By using a highly viscous substance as a filler, the optical fiber 32 can be securely fixed without exerting an excessive pressing force such as applying a bending strain to the optical fiber 32 constituting the optical fiber coil 81. It is.

For this, those having the above-mentioned storage consistency are preferable. If the storage consistency is less than 5, the loss on the long wavelength side due to microbending of the optical fiber 32 (optical fiber coil 81) becomes too large, which is not practical. Further, if the storage consistency exceeds 200, the shape of the optical fiber coil 81 cannot be maintained by the filler 84, so that the coil bundle state collapses during use and the transmission characteristics are stabilized. Can not do.

The filler 84 is also provided between the optical fibers 32.
Is filled, the pressing force applied to each optical fiber 32 is equalized, so that microbend loss caused by irregular lateral pressure can be suppressed, and fine bending, which has been difficult to use conventionally because it is weak to such bending distortion. Diameter fiber (outer diameter of glass part 11 is 100 μm or less) and nonlinearity are improved Δ
An optical fiber coil 81 using a fiber having a small n can be easily manufactured. That is, since the optical component P of the present embodiment includes such a filler 84, the optical fiber 32 having an outer diameter of 100 μm can be used. By using such a small-diameter fiber, the optical component P Can be downsized.

Similarly, an optical fiber which is similarly vulnerable to bending strain and has been difficult to use conventionally, that is, a bending loss of 1 d when bent to a diameter of 20 mm at a wavelength within the operating wavelength band.
The use of an optical fiber of B / m or more has become possible.

Further, the optical fiber 32 (optical fiber coil 81) in the optical component P of the present embodiment is composed of only the glass portion 11 and has no coating layer as described above (in the present embodiment, the coating layer 13, 15 were removed). Therefore, unnecessary side pressure or the like applied to the glass portion 11 of the optical fiber 32 by the coating layer is eliminated, and microbending caused by such side pressure is not generated. As a result, an optical component P (optical fiber coil 81) having excellent transmission loss can be obtained. In addition, the phenomenon that the transmission characteristics change due to the change in the Young's modulus with respect to the temperature of the coating layer and the difference in the expansion coefficient between the coating layer and the glass portion 11 also occurs in the optical fiber 32 composed of only the glass portion 11.
Can be solved by using.

Here, the glass portion 11 having no coating layer
The above-described filler 84 plays an important role in realizing the optical fiber coil 81 using the optical fiber 32 composed only of the filler. That is, since the entire periphery of the optical fiber 32 composed of only the glass portion 11 is wrapped and held by the filler 84, the optical fiber 32 is protected by the filler 84, and at the same time, the optical fiber 32 (the optical fiber coil 81) is vibrated or the like. Roll collapse can be prevented. As a result, extremely stable transmission characteristics can be obtained for a long period of time. Further, as described above, when a small-diameter optical fiber is used as the optical fiber 32, microbends are likely to occur due to disturbance. However, by enclosing with the filler 84, disturbance applied to the optical fiber 32 can be reduced, and transmission loss can be reduced. (Particularly, loss on the long wavelength side of the used wavelength band) can be suppressed.

Further, unnecessary light generated at the connection portion of the optical fiber propagates through the clad. By making the refractive index of the filler 84 larger than the refractive index of the clad, the light generated at the connection portion of the optical fiber is increased. Can efficiently escape out of the optical fiber.

Further, in the optical component P of this embodiment,
Filler 84 is quantified by total digestion as described above.
Na⁺Ion and K⁺Ion (positive ion
Pure substance) has a weight concentration of 0.1 to 6 ppm,
Cl determined by decomposition method ^-Ion (negative ion
Having a weight concentration of 0.5 to 10 ppm
Quality, the optical fiber coil 81
The optical fiber 32 and the filler are stored in the
84 contact with each other and be charged with different signs of static electricity
Of the optical fiber 32 is suppressed,
32 can be prevented from being charged with static electricity having different signs.
And In this manner, the optical fibers 32 have different signs.
Since the electrostatic charge is suppressed, the adjacent optical fiber
The electrostatic attraction generated between the fibers 32 is reduced, and the optical fiber
The side pressure generated by the contact between the bars 32 is reduced.
Can be As a result, the optical fiber coil 81
Microbend loss during
Stabilizes the transmission characteristics of the iva coil 81 (optical component P)
Can be

After leaving the filler 84 in a 1% aqueous NaCl solution at 50 ° C. for 240 hours, the weight concentration of Na ⁺ ions determined by the total decomposition method is twice or less the initial value and 1 ppm or less, and Since the weight concentration of Cl ^- ions determined by the method is twice or less the initial value and 10 ppm or less, the inflow of the ionic aqueous solution from the optical fiber 32 itself, the storage case 80, or the outside of the optical component P, etc. Is generated, the release of Na ⁺ ions and Cl ⁻ ions as impurity ions is suppressed, so that the charging of the optical fibers 32 to static electricity having different signs is further suppressed. Thereby, the electrostatic attraction generated between the adjacent optical fibers 32 becomes extremely small, and the side pressure generated when the optical fibers 323 come into contact with each other can be further reduced.

As described above, the filler 84 in the optical component P of the present embodiment has a storage consistency specified by JIS K 2220 of 5 to 2 at the measured temperature + 23 ° C.
Since the substance is in the range of not more than 00, the optical fiber 32 and the filler 84 come into contact with each other and are charged with static electricity having different signs from each other at a general use temperature of the optical component P, so that the optical fiber 32 and the filler are filled. Even when an electrostatic attractive force acts between the optical fiber 32 and the material 84, the side pressure applied to the optical fiber 32 can be reduced by setting the storage consistency specified in JIS K 2220 to 5 or more. It is possible to suppress an increase in long wavelength side loss due to microbend loss. The filling material 84 is JIS
The storage consistency specified in K2220 is measured temperature +2
By using a substance of 200 or less at 3 ° C., the shape of the optical fiber coil 81 can be reliably maintained, and the optical fiber coil 81 is prevented from being collapsed during use. The transmission loss of the (optical component P) can be further stabilized.

The filler 84 is made of JIS K 222
Since the storage consistency specified as 0 is 5 or more at the measurement temperature of −40 ° C. and 200 or less at the measurement temperature of + 100 ° C., the microbend of the optical fiber 32 is within the practical use temperature range of the optical component P. The loss on the long wavelength side due to the loss can be suppressed from increasing, and the transmission loss of the optical fiber coil 81 (optical component P) can be further stabilized.

As described above, the filler 84 in the optical component P of the present embodiment has a volume resistivity specified by JIS K 6911 of 2 × 10 ¹⁴ Ω · at a measurement temperature of -5 to + 50 ° C. cm or more, when the optical component P is used as a dispersion compensator, the optical fibers 32 are charged with static electricity having different signs and adhere to each other within the operating temperature range of the dispersion compensator. Is suppressed, micro-bend loss in the optical fiber coil 81 can be suppressed, and the transmission characteristics of the optical fiber coil 81 (optical component P) can be stabilized.

The filler 84 is made of JIS K 691
The volume resistivity specified in 1 is a measurement temperature of -40 to + 85 ° C
Is within the range of 1 × 10 ^{13 to} 5 × 10 ¹⁶ Ω · cm, especially when the optical component P is applied as a dispersion compensator, the storage and use temperature range of the dispersion compensator. In this case, it is possible to suppress the optical fibers 32 from being charged with different signs of static electricity and to be brought into close contact with each other, to suppress microbend loss in the optical fiber coil 81, and to transmit the optical fiber coil 81 (optical component P). Characteristics can be stabilized.

As described above, the amount of hydrogen generated from the filler 84 in the optical component P of this embodiment after the temperature deterioration test at 60 ° C. for 24 hours is 0.001 ml / g or less. If hydrogen penetrates into the glass portion 11 (particularly the core) of the optical fiber 32, the transmission loss will be worsened. For this reason, the transmission characteristics of the optical fiber coil 81 (optical component P) can be improved by using, as the filler 84, a material having a hydrogen generation amount of 0.001 ml / g or less after a temperature deterioration test at 60 ° C. for 24 hours. It is possible to maintain good. If the above-mentioned amount of hydrogen generation exceeds 0.001 ml / g, the amount of hydrogen generated from the filler 84 increases, so that the transmission characteristics of the optical fiber coil 81 (optical component P) deteriorate. From the above, it is possible to suppress an increase in loss of the optical fiber 32 due to hydrogen generated from the filler 84 penetrating into the optical fiber 32,
An optical component P suitable for practical use can be obtained. In the present embodiment, the infiltration of hydrogen into the optical fiber 32 is also prevented by forming the above-described thin film on the outer peripheral surface of the clad.

In this embodiment, the filler 84
It was intended to reduce the amount of hydrogen generated itself,
The same effect can be obtained by making the filler 84 contain a substance that absorbs hydrogen. If the filler 84 contains a hydrogen absorbing substance, hydrogen can be adsorbed by the contained hydrogen absorbing substance even if the filler 84 generates hydrogen. As a result, hydrogen does not act on the optical fiber 32, and it is possible to prevent the transmission characteristics of the optical fiber coil 81 (optical component P) from deteriorating. Pd (palladium) alloy, La (lanthanoid) -Ni alloy, La-Ni
-Mn alloy, La-Ni-Al alloy, V (Vanadium)-
There is a Ti-Cr alloy or the like.

In the optical component of the present invention, a test was conducted to confirm the effect of reducing transmission loss obtained by filling the storage case containing the optical fiber coil with the filler. FIG. 6 shows the results. FIG. 6 shows a change in transmission loss with respect to wavelength. As Example 1 according to the present invention, the one of the above-described embodiment was used. On the other hand, in Comparative Example 1, the optical fiber was not removed when the optical fiber was wound around the bobbin, and the optical fiber was housed in the storage case with the optical fiber wound around the bobbin, and the filler was not filled. And Comparative Example 2 has a configuration in which static electricity is removed when an optical fiber is wound around a bobbin, and the optical fiber is housed in a storage case while being wound around a bobbin, and is not filled with a filler. Comparative Example 3 has a configuration in which static electricity is removed when an optical fiber is wound around a bobbin, and the optical fiber is stored in a storage case with the optical fiber removed from the bobbin, and is not filled with a filler. Except for these points, the configurations of Example 1 and Comparative Examples 1 to 3 were completely the same.

As can be seen from FIG. 6, the first embodiment according to the present invention has better transmission characteristics.
In particular, it can be seen that the improvement on the long wavelength side is remarkable.

Next, a method of manufacturing the above-described optical component P will be described.

First, an optical fiber having the coating layers 13 and 15 as shown in FIG. 3B is wound a plurality of times around a bobbin as a central body to form a coil bundle (coiling step). Next, the optical fiber in the coil bundle state is removed from the bobbin in the coil bundle state (optical fiber removing step). Then, the micro-bend that has already occurred is eliminated by giving a slight vibration or the like in the detached state.

In order to remove the optical fiber in the coil bundle state from the bobbin and unwind it, before winding the optical fiber around the bobbin as disclosed in Japanese Patent Application Laid-Open No. Hei 10-123342, it is necessary to previously wrap the optical fiber around the bobbin body. It is preferable to apply a lubricant such as powder before extracting. In this slip,
Talc (physical and chemical dictionary, 4th edition, page 239) used as a powdered inorganic filler can be used. Alternatively, by using a bobbin capable of reducing the body diameter, the optical fiber may be wound and then the body diameter of the bobbin may be reduced to facilitate the removal. The tension at the time of winding the optical fiber around the bobbin is preferably small, and particularly preferably 0.4 N or less.

Next, the entire coil bundle removed is put into a solvent such as sulfuric acid or acetone. As a result, the coating layers 13 and 15 are dissolved in the solvent, and become the optical fiber 32 composed of only the glass portion 11, that is, the optical fiber coil 81 is formed. (Coating removal step). Although a thin film of carbon coating is applied on the outer peripheral surface of the glass portion 11, this thin film does not dissolve in the solvent.

Then, the optical fiber 32 (the optical fiber coil 81) in the coil bundle state from which the coating has been removed is stored in the storage case 80 (storage step).
The filler 84 is filled, and the entire optical fiber 32 is wrapped by the filler 84. At this time, the filler 84 is filled in the storage case 80 and has a fluidity of a low level, and after being filled in the storage case 80 so as to wrap the entire optical fiber 32, the filler 84 is cured, and the optical fiber 32 is hardened. (Filling step).

This curing method includes thermal curing and ultraviolet curing depending on the properties of the resin used as the filler 84.
In the case of thermal curing, for example, the resin is cured by heating at 50 ° C. for 24 hours. The preferred storage consistency described above relates to the cured filler.

The filling material 84 when filling the storage case 80 has a surface tension of 400 μN in order to prevent bubbles and the like from being generated between the optical fibers 32 in the coil bundle state.
/ Cm ² or less. It is also preferable that the viscosity be kept at 10 N · s / m ² or less so that the filler 84 sufficiently penetrates between the optical fibers 32.
Further, when the filler 84 is cured, it is preferable that the viscosity is maintained at 10 N · s / m ² or less for at least two hours from the start of curing. In this case, the filler 84 sufficiently penetrates between the optical fibers 32 and can prevent unnecessary microbends from being generated in the optical fibers 32.

As the filler 84, as described above, a thermosetting or ultraviolet curable silicone resin,
Alternatively, a high-viscosity jelly-like admixture obtained by swelling rubber such as butadiene or silicone with a solvent such as silicone or naphthene and adding other resins or the like as necessary can be used. By using a highly viscous and highly viscous material as the filler 84 as described above, the optical fiber 32 is securely fixed without exerting an excessive pressing force such as a bending strain on the optical fiber 32. This is possible as already mentioned.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, an optical fiber coil using a chromatic dispersion compensating optical fiber (DCF) is used, but another optical fiber may be used. For example, a single mode optical fiber, a chromatic dispersion shifted optical fiber, an NZ type chromatic dispersion shifted optical fiber,
An optical fiber coil using an erbium-doped optical fiber or a polarization maintaining optical fiber may be used.

A single mode optical fiber (Single Mode)
Optical-Fiber (also referred to as SMF) is an optical fiber designed mainly for transmitting an optical signal in a wavelength band of 1.3 μm. 1.55μ using this optical fiber
When an optical signal is transmitted in the wavelength band of m, a phenomenon called chromatic dispersion occurs. This chromatic dispersion is compensated by a module (DCFM) of a chromatic dispersion compensating optical fiber. On the other hand, the SMF is also used for compensating an optical signal having a negative chromatic dispersion due to the above-described DCF or the like with its own positive chromatic dispersion. in this case,
It may be modularized for use.

A wavelength dispersion shifted optical fiber (Dispersion S)
hifted optical-Fiber (also called DSF) is 1.55
An optical fiber designed mainly for transmitting an optical signal in a wavelength band of μm. It has the characteristic that the chromatic dispersion value for the 1.55 μm wavelength band is zero.
DSF may be used as an optical fiber for Raman scattering excitation. It may be modularized for use.

NZ type chromatic dispersion shifted optical fiber (Non Ze
ro Dispersion Shifted optical-Fiber: NZ-DSF
In order to reduce the non-linear phenomenon occurring in the case of the DSF described above, the wavelength at which the chromatic dispersion becomes zero is set to 1.55.
This is an optical fiber designed slightly shifted from μm. NZ
-DSF may be used as an optical fiber for Raman scattering excitation.

Erbium-doped optical fiber (Erbium Doped)
Optical-Fiber (also referred to as EDF) is an optical fiber in which erbium ions are added to the core. 0.98μ wavelength
m, 1.53-1.
When the signal light in the wavelength band of 61 μm is made incident, stimulated emission occurs, and the power of the signal light can be amplified. Normally, optical amplifiers (Erbium D
oped optical-Fiber Amplifier (also called EDFA).

A polarization maintaining optical fiber (Polarization Maint)
An aining optical-Fiber (PMF) is an optical fiber that transmits while maintaining linear polarization, and is used for an optical fiber gyro, a polarization mode dispersion compensator, and the like. Usually, it is modularized into PMFM (Polarization Maint
aining optical-Fiber Module).

Also, in FIG. 1, the optical fiber 32 is shown in contact with the bottom surface of the storage case 80. For example, a small amount of the filler 84 is injected into the storage case 80, and then the light The fibers 32 may be housed and the remaining filler 84 may be injected and cured. By doing so, the pressure that the optical fiber 32 receives from the bottom surface of the storage case 80 can be reduced, which is more preferable. In addition, storage case 8
The form of 0 is not limited to the above-described embodiment, and may be a donut type as shown in FIGS. 7 and 8, or a shape having a curved bottom surface instead of a flat surface.

Further, in the above-described embodiment, the coating layers 13 and 15 of the optical fiber are removed. However, the present invention is not limited to this. An optical fiber coil may be formed by winding an optical fiber having the above in a coil shape, and the optical fiber coil may be stored in a storage case.

[0070]

As described above in detail, according to the present invention, it is possible to provide an optical component which suppresses microbend loss and has stable transmission characteristics, and a method of manufacturing this optical component.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical component according to an embodiment of the present invention.

FIG. 2 is a plan view of an optical component (with a lid removed) according to the embodiment of the present invention.

FIG. 3A is a cross-sectional view of an optical fiber used for an optical component according to an embodiment of the present invention, and FIG. 3B is a cross-sectional view of the optical fiber of FIG.

FIG. 4 is a schematic diagram showing a refractive index difference in a sectional direction of the optical fiber of FIG.

FIG. 5 is a diagram showing a relationship between storage consistency and Young's modulus specified in JIS K 2220.

FIG. 6 is a diagram showing a transmission loss between an optical component according to the present invention and an example and a comparative example, and shows a relationship between the transmission loss and the wavelength.

FIG. 7 is a cross-sectional view of a modification of the optical component according to the embodiment of the present invention.

FIG. 8 is a plan view of a modified example (with the lid removed) of the optical component according to the embodiment of the present invention.

[Explanation of symbols]

11: glass part, 13: primary coating layer, 15: secondary coating layer, 32: optical fiber, 44: fused part, 45: pigtail fiber, 80: storage case, 81: optical fiber coil, 82: lid, 84 ... filler, P ... optical parts.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Fujii 1F Tayacho, Sakae-ku, Yokohama-shi, Kanagawa F-term (reference) in Yokohama Works, Sumitomo Electric Industries, Ltd. 2H038 AA02 AA24 CA31 5F072 AB09 AK06 JJ05

Claims (12)

[Claims] 1. An optical fiber coil comprising an optical fiber wound in a coil shape, a storage case for storing the optical fiber coil, and the storage case in a state of directly contacting an outer peripheral surface of the optical fiber. And a filler filled therein. The filler has a weight concentration of ionic impurities of positive ions of 0.1 to 6 ppm determined by the total decomposition method, and a negative concentration determined by the total decomposition method. An optical component, characterized by being a substance having a weight concentration of ionic impurities of ions of 0.5 to 10 ppm. 2. After the filler is left in a 1% aqueous solution of NaCl at 50 ° C. for 240 hours, the weight concentration of Na ⁺ ions determined by the total decomposition method is not more than twice the initial value and 1%.
ppm Cl is determined by the following and total decomposition ^- Optical component according to claim 1, the weight concentration of ions being a 2 times or less and less than 10ppm substance of the initial value. 3. The filler has a storage consistency specified by JIS K 2220 of 5 or more at a measurement temperature of + 23 ° C.
The optical component according to claim 1, wherein the optical component is a substance in the range of 00 or less. 4. The filler is a substance having a storage consistency specified by JIS K 2220 of 5 or more at a measurement temperature of −40 ° C. and 200 or less at a measurement temperature of + 100 ° C. 2. The optical component according to 1. 5. The filler is a substance having a volume resistivity specified by JIS K 6911 of 2 × 10 ¹⁴ Ω · cm or more at a measurement temperature of -5 to + 50 ° C. 2. The optical component according to 1. 6. The filler is a substance having a volume resistivity specified by JIS K 6911 within a range of 1 × 10 ^{13 to} 5 × 10 ¹⁶ Ω · cm at a measurement temperature of −40 to + 85 ° C. The optical component according to claim 1, wherein: 7. The optical component according to claim 1, wherein the filler is a substance that generates 0.001 ml / g or less of hydrogen after heat treatment at 60 ° C. for 24 hours. 8. The optical component according to claim 1, wherein the filler contains a hydrogen absorbing substance. 9. The optical fiber according to claim 1, wherein at least one of the chromatic dispersion and the chromatic dispersion slope at a wavelength within the wavelength band used is the same as that of the transmission line optical fiber connected to the optical fiber coil. The optical component according to claim 1, wherein the optical component has an opposite sign. 10. The wavelength band used is 1.5 μm.
The optical component according to claim 9, wherein: 11. The optical component according to claim 1, wherein the optical fiber has a bending loss of 1 dB / m or more when the optical fiber is bent to a radius of curvature of 20 mm at a wavelength within the used wavelength band. . 12. A step of winding an optical fiber around a central body, a step of removing the wound optical fiber from the central body to form an optical fiber coil, and a step of storing the optical fiber coil in a storage case. The weight concentration of the ionic impurities of the positive ions determined by the total decomposition method is 0.1 to 6 ppm, and the weight concentration of the ionic impurities of the negative ions determined by the total decomposition method is 0.5 to 10 ppm. Filling the storage case with the filler using a filler.