JP2003021763A - Method of lowering skew of coated optical fiber ribbon, and coated optical fiber ribbon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine an element to detect the skew state of a coated optical fiber ribbon and to lower the skew thereof in accordance with this element. SOLUTION: A plurality of optical fibers S taken up on delivery bobbins 3 are respectively delivered by an accumulator 11 and while the tension thereof is controlled by a tension control dancer 13, the optical fibers are subjected to secondary coating by dies 15 and are taken up as the coated optical fiber ribbon T. At this time, the optical fibers S are temporarily stopped and a refractive index is measured by a refractive index measuring instrument 9 disposed between the delivery bobbins 3 and the accumulator 11. The tension is controlled by the tension control dancer 13 in order to reduce the fiber length difference having a correlation with this refractive index to <=100 μm, more preferably <=50 μm per meter. Since the skew of the fiber length difference and the skew of the coated optical fiber ribbon are correlated, the skew of the coated optical fiber ribbon is lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber ribbon and a method for reducing skew of the optical fiber ribbon.

[0002]

2. Description of the Related Art The conventional communication between computers has been mainly bit serial communication using a fiber channel, but recently, for the purpose of speeding up and high reliability of a computer system, an optical cable using a parallel transmission computer link is applied. Is being actively researched.

A system using the parallel transmission computer link is required to have a low skew optical fiber ribbon. The optical fiber ribbon is composed of a plurality of optical fiber strands, and each optical fiber strand is an optical fiber coated with a primary coating layer such as resin. The skew refers to a transmission time difference between the optical fiber ribbons. Therefore, the low skew tape is an optical fiber tape core wire having a very small difference in signal transmission time between the core wires of the tape.

That is, as one of the optical interconnection techniques, a low-skew optical fiber tape core wire suitable for low-skew tape computer-to-computer transmission, device-to-device transmission, etc. for parallel optical links is required. .

In order to produce a low-skew tape core wire, two factors related to the optical transmission speed must be controlled: (1) the refractive index of the optical fiber, and (2) the physical length of the core wire inside the tape. If you balance these two properly,
It is possible to cancel the delay property due to the difference in refractive index in the fiber by the difference in physical length.

[0006]

In the conventional optical fiber ribbon, the optical fiber ribbon is manufactured even if the skew state of the manufactured optical fiber ribbon is measured and the skew state is known. There is a problem that it is not possible to detect the skew state in the process and reflect it to reduce the skew of the optical fiber ribbon.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to find an element for detecting a skew state of an optical fiber ribbon, and based on this element, an optical system capable of achieving low skew can be achieved. An object of the present invention is to provide a method for reducing skew of a fiber ribbon and an optical fiber ribbon.

[0008]

In order to achieve the above object, the optical fiber ribbon according to the present invention comprises:
An optical fiber ribbon comprising a plurality of optical fiber strands, characterized in that it is coated with a tape material such that the fiber length difference between the optical fiber strands is 100 μm or less per 1 m. To do.

Therefore, the optical fiber ribbon, in which the fiber length difference between the optical fiber strands is 100 μm or less per 1 m, becomes a stable and high-quality tape ribbon with an extremely low skew.

According to a second aspect of the present invention, there is provided a method of reducing skew of an optical fiber ribbon, wherein a plurality of optical fiber wires wound around a sending bobbin are sent out by an accumulator and the tension is controlled by a tension control dancer. Then, when the secondary coating is performed with a die and the fiber is wound as an optical fiber ribbon, a refractive index measuring device provided between the delivery bobbin and the accumulator links the delivery bobbin and the accumulator with each other. The tension is adjusted by the tension control dancer so that the fiber length is temporarily stopped and the refractive index is measured, and the fiber length difference between the optical fiber strands having a correlation with the refractive index is set to 100 μm / m or less. Is controlled to reduce the skew of the optical fiber ribbon.

Therefore, the skew of the optical fiber ribbon is largely dependent on the refractive index difference of the optical fiber and the fiber length difference between the optical fiber strands and is correlated with each other, so that the optical fiber ribbon is manufactured. The tension of each optical fiber strand is adjusted by the tension control dancer based on the refractive index measured by the refractive index measuring device during the process, and the fiber length difference which is the physical length of each optical fiber strand is 1
By controlling to 100 μm or less per m, preferably 50 μm or less, the skew of the optical fiber ribbon can be reduced.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

Referring to FIG. 1, an optical fiber tape core wire manufacturing apparatus 1 used in this embodiment comprises an optical fiber tape core formed from a plurality of optical fiber strands S wound around a delivery bobbin 3. This is an apparatus for manufacturing the wire T. In FIG. 1, a certain amount of optical fiber strands S are wound around a plurality of delivery bobbins 3. Each of these bobbins 3
The optical fiber strands S wound around are fed to the accumulator 11 through the guide rollers 7 and the refractive index measuring device 9 by rotating the respective feeding bobbins 3 by driving the individual motors 5. By driving the accumulator 11, the expansion force of each fiber strand S is adjusted by the tension control dancer 13, and then the die 15 is subjected to secondary coating such as UV coating resin (not shown).
Then, the optical fiber ribbon T is wound on the winding bobbin 21 which is rotated by driving the motor 19 via the lamp 17.

The motor 5, the accumulator 11, the tension control dancer 13 and the motor 19 are controlled by a controller 23. In the refraction index measuring device 9, the refraction index is measured by a lateral interference method capable of nondestructive measurement. Then, the refractive index measuring device 9 actually measures the refractive index at intervals of several tens of meters. That is, the winding bobbin 21 always operates continuously,
On the delivery side, by interlocking the accumulator 11 and the delivery bobbin 3, the optical fiber strands S are stopped in the measurement system only during the refractive index measurement, and the refraction index measuring device 9 refracts each optical fiber strand S. The rate can be measured accurately.

The result of the refractive index measured by the refractive index measuring device 9 is sent to the control device 23, and a signal for tension adjustment is fed back from the control device 23 to the tension control dancer 13 so that each optical fiber strand is fed. The tension of S can be adjusted.

Therefore, the difference in the refractive index between the wires in the longitudinal direction can be canceled online by adjusting the physical length between the wires by the sending tension.

That is, there is a correlation between the refractive index measured by the refractive index measuring device 9 and the physical length (line length) between the wires, and the physical length between the wires (line length) and the tension. Since there is a relationship, the measured value of the refractive index serves as a barometer for adjusting the physical length between the wires, that is, the tension.

Further, the relationship between the physical length between the wires and the skew will be described. As described above, the skew means a transmission time difference (PS / m) between the optical fiber strands S in the optical fiber ribbon core wire T. And the physical length between the above-mentioned strands is the difference in length between the cores (“fiber length difference”).
(Also referred to as “line length difference”) in this embodiment.

Incidentally, the line length difference is obtained by removing all the coating material of the optical fiber ribbon T and then measuring the length difference per unit length.

In this embodiment, a 16-core tape core wire was actually manufactured, and the line length difference and skew were measured.
As shown in FIG. 2, there was a clear correlation between the two. As you can see from Figure 2, skew 1 (PS / m)
In order to achieve the above, it is necessary that the line length difference per 1 m is within 100 μm. However, considering that other factors such as the relative refractive index difference also influence the skew, 50 μ
It can be said that the value within m is preferable.

From the above, the tension for controlling the physical length (line length) based on the measured value of the refractive index is adjusted so that the line length difference is 100 μm or less, preferably 50 μm or less. It is possible to suppress the optical fiber tape core wire T within a skew of 1 (PS / m) in the manufacturing process of the optical fiber tape core wire T by controlling 13 to improve the manufacturability of the low skew tape. You can

Therefore, the optical fiber ribbon T manufactured by the above method so that the fiber length difference between the respective optical fiber strands S is 100 μm or less per 1 m, preferably 50 μm or less, has extremely low skew and high quality. It becomes the optical fiber tape core wire.

The present invention is not limited to the above-described embodiment, but can be implemented in other modes by making appropriate changes.

[0024]

As can be understood from the above description of the embodiment of the invention, according to the invention of claim 1, the fiber length difference between the respective optical fiber element wires in the optical fiber ribbon is per 1 m. Since the thickness is 100 μm or less, it is possible to provide a stable and high-quality optical fiber tape core wire with extremely low skew.

According to the second aspect of the present invention, the skew of the optical fiber ribbon is largely dependent on the refractive index difference of the optical fiber and the fiber length difference between the optical fiber strands, and has a correlation with each other. Since it became clear, the tension of each optical fiber was adjusted by the tension control dancer based on the refractive index measured by the refractive index measuring device during the process of manufacturing the optical fiber ribbon. Since the fiber length difference, which is the physical length of the fiber strand, can be controlled to 100 μm or less per 1 m, preferably 50 μm or less, the skew of the optical fiber ribbon can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic side view showing a manufacturing process of an optical fiber ribbon according to an embodiment of the present invention.

FIG. 2 is a relationship diagram between a line length difference and a skew in an optical fiber ribbon.

[Explanation of symbols]

1 Optical fiber ribbon manufacturing equipment 3 sending bobbin 5 motor 7 Guide roller 9 Refractive index measuring device 11 Accumulator 13 Tension control dancer 15 dice 17 lamps 19 motor 21 winding bobbin 23 Control device S optical fiber T optical fiber ribbon

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Keiji Ohashi             1440 Rokuzaki, Sakura City, Chiba Prefecture Fujikura Ltd.             Sakura office F-term (reference) 2H001 BB14 BB25 KK17 MM04 MM08

Claims (2)

[Claims] 1. An optical fiber tape core wire composed of a plurality of optical fiber wires, wherein the optical fiber tape core wire is covered with a tape material such that the fiber length difference between the optical fiber wires is 100 μm or less per 1 m. An optical fiber tape core wire characterized in that 2. A plurality of optical fiber strands wound on a delivery bobbin are delivered by an accumulator, and the tension is controlled by a tension control dancer.
When the next coating is performed and when wound as an optical fiber tape core wire, a refractive index measuring device provided between the delivery bobbin and the accumulator, the optical fiber strand is temporarily operated by interlocking the delivery bobbin and the accumulator. By controlling the tension by the tension control dancer so that the fiber length difference between the optical fiber strands having a correlation with the refractive index is 100 μm or less per 1 m And a method for reducing the skew of the optical fiber ribbon, wherein the skew of the optical fiber ribbon is reduced.