JP2001108839A - Dispersion compensating optical fiber module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dispersion-compensated optical fiber module which has its polarization mode dispersion reduced. SOLUTION: This dispersion-compensated optical fiber module equipped with a cylindrical body part 3 and disklike collar parts 2 fitted to both its end surfaces 22 and includes a reel 1 having buffer materials 10 fitted to the internal surface 21 of the collar part 2 in contact with the body part 3 and the outer peripheral surface 20 of the body part 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dispersion compensating optical fiber module.

[0002]

2. Description of the Related Art Recently, erbium-doped optical fiber amplifiers have been widely used.
In place of the 3 μm band, systems such as ultra-long distance non-regenerative relay using the 1.55 μm band and optical subscriber multi-distribution networks are being studied for practical use.

For transmission in the 1.55 μm band, it is desirable to use a 1.55 μm dispersion-shifted fiber having a zero dispersion wavelength of 1.55 μm.
1.55μm using μm band single mode optical fiber
If the band light can be transmitted with low dispersion, there is no need to lay a new 1.55 μm dispersion-shifted fiber cable, which is very advantageous in terms of laying cost and the like. However, the single-mode optical fiber cable in the 1.3 μm band has a zero dispersion wavelength of 1.3 μm, and when transmitting in the 1.55 μm band, large chromatic dispersion occurs and the optical signal is deteriorated. Therefore, in order to transmit 1.55 μm light using a 1.3 μm band single mode optical fiber, 1.3 μm light is required.
A method has been proposed in which a 1.55 μm band optical signal is not deteriorated by using a μm band single mode optical fiber and a dispersion compensating optical fiber having a wavelength dispersion characteristic of the opposite sign.

[0004] Such a dispersion compensating optical fiber is wound around a small reel and formed into a coil like an erbium-doped optical fiber for amplifying an optical signal of a certain wavelength.
It is used as a small entrained module housed in a case.

[0005]

However, when a small reel having a small diameter is used to wind the optical fiber around the reel, the winding tension applied to the optical fiber increases, and dispersion compensation on the outer peripheral surface of the reel occurs. When the optical fibers are wound in close contact with each other, side pressure from adjacent fibers is applied. For these reasons, there has been a problem that polarization mode dispersion occurs in the dispersion compensating optical fiber.

Furthermore, in the conventional dispersion compensating optical fiber module reel, when the temperature of the whole module changes, the winding tension and the side pressure applied to the dispersion compensating optical fiber wound on the reel change accordingly.
There is also a problem that temperature dependence is caused in dispersion compensation.

The present invention has been made in view of the above problems, and provides a dispersion-compensating optical fiber module reel in which when a dispersion-compensating optical fiber is wound, side pressure and winding tension applied to the optical fiber are reduced. It is intended to be.

A further object of the present invention is to provide a dispersion compensating optical fiber module having a lower temperature dependency.

[0009]

SUMMARY OF THE INVENTION In order to solve the above problems and achieve the object, the present invention is configured as follows. That is, the dispersion-compensating optical fiber module of the present invention includes a trunk, and flanges attached to both ends of the trunk, and a reel in which a cushioning material is attached to an inner surface of the flange and an outer peripheral surface of the trunk. It is characterized in that a dispersion compensating optical fiber is wound.

Further, the dispersion compensating optical fiber module of the present invention winds the dispersion compensating optical fiber around a body and a reel having flanges attached to both ends thereof and detachable from the body. It is characterized by removing the part.

In the dispersion compensating optical fiber module according to the present invention, at least the trunk of the trunk and the flange of the reel has a linear expansion coefficient equal to or less than that of the dispersion compensating optical fiber wound on the reel. Desirably, it is made of a material.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing one embodiment of a reel used for the dispersion compensating optical fiber module of the present invention. In the drawing, reference numeral 2 denotes a flange portion, reference numeral 3 denotes a body portion, and reference numeral 10 denotes a cushioning material.

This reel has a cylindrical body 3 and disk-shaped flanges 2 attached to both end surfaces thereof. The outer peripheral surface 20 of the body 3 and the flange 2 are connected to the body 3. The cushioning material 10 is attached to the inner side surface 21 of the flange portion 2 which is in contact with.

The body portion 3 is for winding the dispersion compensating optical fiber around its outer circumference, and is a cylindrical member having a diameter of 4 to 10 cm and a height of 0.4 to 20 cm.
The material of the body 3 is not particularly limited as long as the cushioning material 10 is attached to the outer peripheral surface 20 thereof, but silica glass or Invar can be suitably used.

The flange 2 is attached to the end faces 22, 22 of the body 3, and has a diameter of 10 to 30 cm and a thickness of 0.1 to 1.0.
cm, and has a diameter larger than the diameter of the body 3. The material of the flange portion 2 may be the same as or different from the material of the trunk portion 3, but is not particularly limited as long as the cushioning material 10 is attached to the inner side surface 21 of the flange portion 2. Similarly to the above, silica glass or invar can be suitably used.

The cushioning material 10 is made of an elastic material attached to the outer peripheral surface 20 of the body 3 and the inner surface 21 of the flange 2. As the degree of elasticity, the Young's modulus preferably has a value of at least 5 to 80 kg / mm ² . Materials that satisfy this condition include silicone and the like, but silicone is preferred.

The mounting of the body 3 and the flange 2 of the reel 1 in this embodiment is not particularly limited.
They can be fixed to each other by a method such as a screw, a fitting type, a spring or a resin.

In the dispersion compensating optical fiber module of the present invention, 30 dispersion compensating optical fibers are wound around the reel 1 having the above-described structure in the same manner as in a normal method of manufacturing a dispersion compensating optical fiber module. Specifically, the dispersion compensating optical fiber 30 is wound around the reel 1 while applying a constant tension to the body 3 sequentially from one end thereof. At this time, the gap between the dispersion compensating optical fiber 30 and the body 3 and between the adjacent dispersion compensating optical fibers 30 when wound on the reel 1 is 0 to 3 times the outer diameter of the fiber coating. Within the range. Next, the dispersion-compensating optical fiber module is manufactured by placing the module in a case.

Next, another embodiment of the reel used in the dispersion compensating optical fiber module of the present invention will be described with reference to FIGS. The reel 1 shown in FIGS.
It is characterized by comprising a cylindrical body portion 3 and a disk-shaped flange portion 2 attached to both ends thereof and detachable from the body portion 3, and is dispersed on an outer peripheral surface 20 of the body portion 3. The compensating optical fiber 30 is wound. Trunk 3 and collar 2
The fixing method is not particularly limited, but desirably has such a fixing strength that the flange 2 does not easily fall off the body 3 during the work of winding the dispersion compensation optical fiber around the body 3. Specific fixing methods include a screw, a fitting type, a spring and a resin.

FIG. 2 is a side view showing a state where the dispersion compensating optical fiber 30 is wound around the reel 1 for the dispersion compensating optical fiber module. In the lower right part of the body 3 shown in this figure, the outer peripheral surface 20 of the body 3 is intentionally exposed to clarify the structure of the reel 1. A dispersion compensating optical fiber 30 is wound around the outer peripheral surface 20 of the reel 1, and both ends of the dispersion compensating optical fiber are outside the reel 1 (left side in the figure) from near the upper end surface 22 of the body 3.
Extends to

FIG. 3 shows the state of FIG.
It is a side view which shows the state from which the collar part 2 which was 2 and 22 was removed.

FIG. 4 shows the flange 2 as shown in FIG.
FIG. 9 is a side view showing a state in which the bundle of the dispersion compensating optical fibers 30 wound around the outer peripheral surface 20 of the trunk portion 3 is fixed by the resins 35 after removing the. The fixing of the dispersion compensating optical fiber 30 by the resin 35, 35
0 on all the dispersion compensating optical fibers on the outer peripheral surface 20 of the body 3. In this figure, two places are fixed, but it is preferable that they are fixed at at least one place, and when two or more places are fixed, it is preferable that they are fixed at equal intervals.

The resin used for fixing the dispersion compensating optical fiber to the body 3 is not particularly limited, but it is preferable to use the same resin as the fiber coating, since good adhesiveness can be obtained. For example, in the case of a fiber using a UV resin for coating, it is preferable to fix the same using a similar UV resin or the like.

Although not shown in FIG. 2, a cushioning material 10 may be provided on the outer peripheral surface 20 of the body portion 3 of FIG. 2, like the reel 1 shown in FIG.

In the reel 1 for a dispersion compensating optical fiber module according to the present invention, at least the trunk portion 3 of the trunk portion 3 and the flange portion 2 has the dispersion compensating optical fiber 3 wound around the reel 1.
It is preferable to use a material having a coefficient of linear expansion equal to or less than 0. More specifically, the coefficient of linear expansion is 1.0 × 1
Silica glass or Invar of 0 ⁻⁶ / ° C. or less can be suitably used.

As for the reel 1 shown in FIGS. 2 to 4, the dispersion compensating optical fiber 30 is wound around the reel 1 in the same manner as the reel 1 shown in FIG. Then, after the binding of the dispersion compensating optical fibers is maintained by fixing with the resin 35, the flanges 2, 2 are removed from the body 3. When the binding between the dispersion compensating optical fibers is strong, the resin fixing can be performed after the flanges 2 and 2 are removed. Then, the reel 1 around which the dispersion compensating optical fiber 30 is wound is housed in a case to complete the dispersion compensating optical fiber module.

In the above-described dispersion compensating optical fiber module, in the case of the reel 1 shown in FIG. 1, that is, when the cushioning material 10 is provided on the outer peripheral surface 20 of the body 3 and the inner surface 21 of the flange 2. Can reduce side pressure and winding tension applied to the dispersion compensating optical fiber when the dispersion compensating optical fiber 30 is wound around a reel.

In the above-described dispersion compensating optical fiber module, in the case of the reel shown in FIGS. 2 to 4, that is, when the reel 1 of the type in which the flange 2 can be detached from the body 3 is used, After the compensating optical fiber 30 is wound, it is possible to easily remove the side pressure from the flanges 2 and 2.

Further, in the dispersion compensating optical fiber module described above, at least the trunk 3 of the trunk 3 and the flange 2 of the reel 1 is equal to or less than the dispersion compensating optical fiber 30 wound around the reel 1. By using a material having an expansion coefficient, the temperature dependence of the dispersion compensation ability of the dispersion compensation optical fiber wound around the outer peripheral surface 20 of the body 3 can be reduced.

[0030]

EXAMPLES Example 1 A dispersion compensating fiber module having the following dimensions was manufactured.

The material was made only of Invar. The flange was fixed to the trunk with screws. The distance between the dispersion-compensating optical fibers (coating outer diameter 250 μm) wound around the body was twice as large as the fiber coating. The temperature fluctuation of the polarization dispersion (PMD) of the manufactured dispersion compensating optical fiber module was measured. For the measurement, a polarization analyzer 8509B manufactured by Hewlett-Packard Company and 8168E were used as a light source. The measurement temperature is -20 ℃,
The temperature was set to 25 ° C. and 70 ° C., and measured by the Jones matrix method.

Comparative Example 1 A dispersion compensating optical fiber module was manufactured in the same manner as in Example 1 except that the material used was aluminum. Further, the temperature fluctuation of the polarization dispersion was measured in the same manner as in Example 1.

Example 2 A dispersion-compensating optical fiber module was manufactured in the same manner as in Example 1 except that the intervals between the dispersion-compensating optical fibers wound around the body were set to 0, 500, and 750 μm. In the same manner as in Example 1 and Comparative Example 1, the polarization dispersion of each dispersion compensating optical fiber module was measured.
The measurement temperatures were −20 ° C., 0 ° C., 25 ° C., and 70 ° C.

(Results) (Comparison between Example 1 and Comparative Example 1) Example 1 (product of the present invention)
FIG. 5 shows the measurement results of the temperature dependence of the polarization dispersion in Comparative Example 1 and the comparative example 1 (conventional product). As is clear from this figure, the product of the present invention has lower temperature dependence of polarization dispersion than the conventional product. In particular, it is understood that the polarization dispersion is small when the temperature changes between 25 ° C and -20 ° C.

(Effect of Fiber Spacing at Body on Polarization Dispersion Temperature Fluctuation) The results of measurement of the temperature fluctuation of the polarization dispersion at different fiber spacings of the dispersion compensating optical fiber wound around the body. Is shown in FIG. As is apparent from this figure, the temperature fluctuation of the polarization dispersion differs depending on the fiber interval, and it can be seen that the temperature fluctuation is low when the interval is 750 μm.

[0036]

According to the dispersion compensating optical fiber module of the present invention, the winding tension and the side pressure of the dispersion compensating optical fiber are controlled by the cushioning materials provided on the outer peripheral surface of the body of the reel and the inner surface of the flange included in the module. Can be reduced together.

Further, the dispersion compensating optical fiber module of the present invention is configured so that the flanges attached to both end surfaces of the body of the reel included therein can be removed, so that the dispersion compensating optical fiber is wound around the body. After turning, the side pressure applied to the dispersion compensating optical fiber can be removed by removing the flange from the body.

Further, according to the dispersion compensating optical fiber module of the present invention, at least the material of the trunk portion and the flange portion is made of a material having a linear expansion coefficient equal to or less than that of the dispersion compensating optical fiber wound on the reel. Therefore, it is possible to reduce the temperature dependence of dispersion compensation when the temperature of the module changes.

Further, since the dispersion compensating optical fiber module of the present invention is not greatly different in form from the conventional one, it is possible to wind the fiber around the reel in the conventional manner. It can be easily manufactured without complication.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a reel for a dispersion compensating optical fiber module of the present invention.

FIG. 2 is a side view showing another embodiment of the dispersion-compensating optical fiber module reel of the present invention.

FIG. 3 is a side view showing a state where a flange is removed from the reel of FIG. 2;

FIG. 4 is a side view showing a state in which a bundle of dispersion-compensating optical fibers wound around a reel in FIG. 3 is bonded and fixed with a resin.

FIG. 5 is a graph showing measurement results of temperature fluctuations of polarization dispersion of the dispersion compensating optical fiber modules of Example 1 and Comparative Example 1.

FIG. 6 is a graph showing the effect of the spacing between the fibers of the dispersion compensating optical fiber wound around the body on the temperature fluctuation of polarization dispersion.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... reel, 2 ... flange part, 3 ... trunk part, 10 *
..Cushion material, 20 ... outer peripheral surface, 21 ... inner surface, 2
2 ... End face.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeshi Seki 1440, Mukurosaki, Sakura City, Chiba Prefecture Inside Fujikura Sakura Office, Inc. 72) Inventor Akira Wada 1440, Murosaki, Sakura-shi, Chiba Prefecture Fujikura Co., Ltd. Sakura Plant F-term (reference) 2H038 AA24 CA35 2H050 AB03Z AD01 AD16

Claims (3)

[Claims] 1. A dispersion compensating optical fiber is wound around a reel having a body portion and flange portions attached to both ends thereof, and a cushioning material attached to an inner surface of the flange portion and an outer peripheral surface of the body portion. A dispersion-compensating optical fiber module that is turned. 2. A dispersion compensating optical fiber module in which a dispersion compensating optical fiber is wound around a reel having a body and flanges attached to both ends thereof and detachable from the body, and the flange is removed. . 3. The reel according to claim 1, wherein at least the trunk portion of the trunk portion and the flange portion is made of a material having a linear expansion coefficient equal to or less than that of the dispersion compensating optical fiber wound on the reel. Item 3. The dispersion compensating optical fiber module according to item 1 or 2.