JPH04366902A - Excessive-length processing method for optical fiber cable - Google Patents

Abstract

PURPOSE:To reduce the size of a device by reducing the size of an excessive- length processing part for the optical fiber cable. CONSTITUTION:The carbon-coated optical fiber cable 21 is wound spirally in plane view to form a flat coil. This flat coil is embedded in a resin material and molded in a flat plate shape to obtain an excessive-length processing plate 22. The flat coil is held in the fixed shape with the resin material, so the carbon-coated optical fiber cable can be wound and held without using any bobbin. Therefore, the thickness of the excessive-length processing part is reduced, so the height of the unit of an optical fiber unit is made short.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing excess length of an optical fiber cable in an optical fiber amplifier using an erbium-doped optical fiber cable.

0002

2. Description of the Related Art Conventionally, erbium-doped optical fiber cables used in optical fiber amplifiers require a length of several hundred meters in order to obtain a desired gain. For this reason, one of the challenges within the optical fiber amplifier unit is how to deal with the extra length of the optical fiber cable, which can be several hundreds of meters long. Figure 5 shows the structure of a conventional general optical fiber cable.
This is explained by

FIG. 5 is a perspective view showing the terminal portion of a conventional optical fiber cable. In the figure, 1 is a conventional optical fiber cable, and this optical fiber cable 1 consists of an optical fiber 2 made of quartz or the like, a primary coating 3 made of silicone resin provided around it, and a nylon resin a tension member 5 made of aramid fiber for increasing mechanical strength, and a PVC
It consisted of an outer jacket 6 etc. Incidentally, even an erbium-doped optical fiber cable had the same structure as that described above. Since the optical fiber cable 1 has an outer diameter of nearly 1 mm even with the secondary coating 5, if an extra length of several hundred meters is to be processed, the area and volume occupied by the extra length will be enormous. became. Conventionally, extra length processing was performed by winding the optical fiber cable 1 around a bobbin, as shown in FIGS. 6 and 7.

FIG. 6 is a perspective view of a bobbin used in the conventional surplus length processing method. FIG. 7 is a perspective view showing a state in which an optical fiber cable is wound around a bobbin. In these figures 7
indicates a bobbin. When the optical fiber cable 1 is wound around the bobbin 7 shown in FIG. 6 as shown in FIG. 7, the height of the bobbin 7 is several tens of mm, and the diameter is several hundred mm. For example, assuming that the length of the optical fiber cable 1 is 200 m and the height of the bobbin 7 is 20 mm, the diameter of the bobbin 7 will be approximately 300 mm. Therefore, this bobbin 7
In order to downsize the primary coating 3, only the small diameter of the primary coating 3 is often wound around the bobbin. Assuming that the diameter of the primary coating 3 is, for example, 0.25 mm and the height of the bobbin 7 is 20 mm, the outer diameter of the bobbin 7 can be reduced to about 50 mm. It should be noted that it is obvious that the height will increase if the outer diameter is made smaller, and in reality, a middle-sized solution is adopted. In recent years, a carbon-coated optical fiber cable in which the primary coating of an optical fiber is coated with carbon has been developed. This was developed based on the fact that carbon is inorganic and has excellent airtightness. It has been reported that compared to conventional silicone resins, there is an improvement in aging deterioration due to improved hydrogen resistance, and an improvement in static fatigue characteristics. The structure of this carbon-coated optical fiber cable is shown in FIG.

FIG. 8 is a perspective view showing the terminal portion of a conventional carbon-coated optical fiber cable. In the same figure, 8
1 is a carbon coated optical fiber cable, which is made up of an optical fiber strand 2, a primary coating 9, and a secondary coating 10. The primary coating 9 is one in which carbon is coated on its outer peripheral surface by a CVD method (chemical vapor deposition method), and the thickness of the carbon is approximately several tens of nanometers. Furthermore, UV resin is considered as the secondary coating 10, and some of the secondary coatings 10 have a diameter of about 0.25 mm. In addition, as an example of coating the primary coating of an erbium-doped optical fiber cable with the above-mentioned carbon to process the excess length, see "Akira Oibe et al.; Hermetic Er fiber coil for optical amplification module; 1990 Institute of Electronics, Information and Communication Engineers Autumn National Conference. There is "Convention C-274". This example is also an example in which an optical fiber cable is wound around a bobbin, but the bobbin is smaller than the conventional silicone resin type primary covering material, with an outer diameter of 32 mm and a height of about 20 mm.

[0006]

[Problem to be solved by the invention] However, even in this case, it cannot be said that it is sufficient to meet the recent demand for miniaturization of optical communication equipment, and as shown in FIG. There was a need to reduce the size. FIG. 9 is a cross-sectional view showing the schematic configuration of a conventional optical fiber amplifier.
1 is an optical fiber amplifier unit, and 12 is a pumping semiconductor laser module installed in this unit 11. As shown in the figure, unit 1 of the optical fiber amplifier
When housing the bobbin 7 in the unit 1, even if the excitation semiconductor laser module 12 and the like can be downsized, the height of the unit 11 must be made larger than necessary due to the large height of the bobbin 7. You won't get any more.

[0007]

[Means for Solving the Problems] A method for processing excess length of an optical fiber cable according to the present invention involves winding a carbon-coated optical fiber cable in a spiral shape in a plan view to form a flat coil, and then inserting the flat coil into a resin material. It is buried and formed into a flat plate.

[0008]

[Operation] Since the flat coil is kept in a constant shape by the resin material, the carbon coated optical fiber cable can be wound and held without using a bobbin.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 3. FIG. 1 is a perspective view of an extra length processing plate formed by the method for processing extra length of an optical fiber cable according to the present invention, FIG. 2 is a sectional view of the extra length processing plate, and FIG. FIG. 2 is a cross-sectional view showing a state in which an extra length processing plate formed by an extra length processing method is installed in an optical fiber amplifier unit. In these figures, 21 is a carbon-coated erbium-doped optical fiber cable. This optical fiber cable 21 is formed similarly to that shown in FIG. 8 above.

Reference numeral 22 denotes an extra length treatment plate for keeping the carbon-coated erbium-doped optical fiber cable 21 in a constant shape. The extra length treatment plate 22 is made of a plastic molded plate, and the carbon-coated erbium-doped optical fiber cable 21 is embedded inside it. The carbon-coated erbium-doped optical fiber cable 21 is tightly wound in a spiral shape in a plan view to form a spiral coil, and is also wound vertically in multiple layers as shown in FIG. ing. Then, the flat spiral coil is molded in plastic and embedded in the extra length processing plate 22. Note that in FIG. 2, the central portion of the spiral coil is omitted. Further, reference numeral 23 in the figure is a mounting hole for mounting the extra length processing plate 22 to the unit 11 of the optical fiber amplifier.

Furthermore, by winding the carbon-coated erbium-doped optical fiber cable 21 into a spiral coil as described above, the dimensions after winding are larger than those of a conventional bobbin, but
The height or thickness dimension becomes smaller. For example, if there is only the primary coating 9 that does not cover the UV resin of the secondary coating 10 shown in FIG. 8, its outer diameter is 0.125 mm, so if this is allowed to be up to a thickness of about 2.5 mm, there will be 20 layers. Can be stacked. At this time, the outer diameter of the spiral becomes approximately 100 mm.

Next, a method for processing the excess length of an optical fiber cable according to the present invention will be explained in detail. First, the carbon-coated erbium-doped optical fiber cable 21 is wound and temporarily held in a flat coil shape with a thickness of about 2.5 mm and a spiral outer diameter of about 100 mm using, for example, a specialized electric wire coil winding machine. Then, this flat coil is made into a 2.5 mm thick, 1.
Form into a 00mm square plate. In this way, the extra length treated plate 22 as shown in FIGS. 1 and 2 is obtained. Thereafter, as shown in FIG.
00m surplus length processing is completed. The carbon-coated erbium-doped optical fiber cable 21 has a heat resistance temperature of 5.
Since the temperature is up to about 00°C, it can sufficiently withstand the plastic molding temperature when molding the extra length treatment plate 22. Furthermore, since the adhesion strength is higher than that of silicone resin, there is no risk of damage during spiral molding. Furthermore, due to its excellent airtightness, even resins containing harmful substances such as hydrogen are less likely to be adversely affected, and the resin used can be used in any particular way, making it easy to form spiral coils and plastic molds. You will be able to do this.

Therefore, according to the surplus length processing method of the present invention, since the flat coil is kept in a constant shape with the resin material, it is possible to wind and hold the carbon coated optical fiber cable without using a bobbin. . Therefore, the thickness of the extra length processed portion can be reduced. In addition, the extra length processing plate 22
Although the area of the top surface is larger than that of a conventional bobbin, since the optical fiber amplifier unit 11 also accommodates other components indicated by the reference numeral 24 in FIG. Must not be. Rather, Figure 3
By mounting the extra length treatment plate 22 vertically overlapping other components 24 in the optical fiber amplifier unit 11 as shown in FIG. 2, the installation area of the drum can also be reduced.

Although this embodiment shows an example in which the flat coil is embedded in the extra length processing plate 22, it can also be constructed as shown in FIG. 4. FIG. 4 is a sectional view showing another example of an extra length processing plate formed by the method for processing extra length of an optical fiber cable according to the present invention. Extra length processing plate 31 shown in the figure
The flat coil 32 is sandwiched between two metal or plastic thin plates 33, and these are bonded together with an adhesive 34 to form a laminated plate shape. Even in this case, the same effect as that of this embodiment can be obtained.

[0015]

Effects of the Invention As explained above, the method for processing the excess length of an optical fiber cable according to the present invention involves winding a carbon-coated optical fiber cable in a spiral shape in a plan view to form a flat coil, and then rolling this flat coil in a resin material. Since the flat coil is embedded in the coil and formed into a flat plate shape, the flat coil is kept in a constant shape by the resin material, so the carbon-coated optical fiber cable can be wound and held without using a bobbin. Therefore, since the thickness of the extra length portion is reduced, the height of the optical fiber amplifier unit can be reduced. That is, it becomes possible to downsize the optical communication device.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an extra length processing plate formed by the method for processing extra length of an optical fiber cable according to the present invention.

FIG. 2 is a sectional view of an extra length processing plate formed by the method for processing extra length of an optical fiber cable according to the present invention.

FIG. 3 is a cross-sectional view showing a state in which an extra length processing plate formed by the method for processing extra length of an optical fiber cable according to the present invention is installed in an optical fiber amplifier unit.

FIG. 4 is a sectional view showing another example of an extra length processing plate formed by the method for processing extra length of an optical fiber cable according to the present invention.

FIG. 5 is a perspective view showing the terminal portion of a conventional optical fiber cable.

FIG. 6 is a perspective view of a bobbin used in a conventional surplus length processing method.

FIG. 7 is a perspective view showing a state in which an optical fiber cable is wound around a bobbin.

FIG. 8 is a perspective view showing the terminal portion of a conventional carbon-coated optical fiber cable.

FIG. 9 is a sectional view showing a schematic configuration of a conventional optical fiber amplifier.

[Explanation of symbols]

21 Carbon coated erbium doped optical fiber cable 22 Excess length processing plate 34 Adhesive

Claims (1)

[Claims] 1. A residual optical fiber cable characterized in that a carbon-coated optical fiber cable is spirally wound in a plan view to form a flat coil, and then the flat coil is embedded in a resin material and formed into a flat plate shape. Long processing method.