JP2000275014A - Skew measurement method and skew measurement system - Google Patents

Abstract

(57) [Abstract] [Problem] To accurately measure skew of a multi-core fiber with a compact measuring system without taking up space. SOLUTION: At least one bobbin 4 having the same radius
The skew is measured using the tape-type optical fiber 10 whose front surface and back surface are respectively wound several times with respect to a and 4b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a skew measuring method and a skew measuring apparatus, and more particularly to a method of measuring a skew of a tape-type optical fiber used as a transmission medium in parallel optical transmission. That is, the present invention relates to a skew measurement method and a skew measurement system capable of accurately measuring skew.

[0002]

2. Description of the Related Art Conventionally, an optical fiber having a small diameter and EMC compatibility is suitable as a transmission medium for large-capacity data transmission in a communication system device or the like. In addition, "EMC compatibility" means
This means that optical fibers are less likely to receive and emit electromagnetic noise than electric wires.

[0003] A multi-core tape-type optical fiber is used as a transmission medium for parallel transmission of multiple channels.

[0004] In the multi-channel parallel transmission, a problem of variation in transmission delay between channels, that is, skew is a problem.

In the case of a tape type optical fiber, the skew is
It is distributed continuously in the track direction. Therefore, it increases in proportion to the line length, and usually “ps (= pico second)
d) / m ”as a unit.

Therefore, in the construction of the optical parallel transmission system, it is essential to reduce the skew of the tape type optical fiber.

However, the skew of the tape-type optical fiber is easily affected by various conditions, and the measured skew value may vary.

Therefore, in order to accurately measure the skew value, the following attention is required.

FIG. 9 is a sectional view of a 12-core optical fiber ribbon.

[0010] The tape-type optical fiber core 1 is composed of a plurality of optical fiber strands 2 arranged side by side in a row and subjected to a secondary coating to be integrated into a tape shape.

At this time, the arranged optical fiber wires 2
Are not perfectly aligned, and are unavoidably uneven in the thickness direction when viewed finely.

The tape-type optical fiber 1 is usually stored in a state wound around a bobbin 3 as shown in FIG. However, when the tape-type optical fiber core wire 1 is wound around a cylinder, the optical fibers 2 have a difference in radius of a wound circle due to the above-mentioned irregularity in the thickness direction. In the state of being wound on the bobbin 3, the difference accumulates and affects the skew value of the tape type optical fiber 1, so that accurate skew measurement cannot be performed.

FIGS. 11 and 12 show examples of skew measurement of a four-core optical fiber ribbon.

FIG. 11 shows the result of measurement of the tape-type optical fiber in a state where the optical fiber is unwound from the bobbin and extended. This measurement result represents an accurate skew value of the tape-type optical fiber core.

On the other hand, FIG. 12 shows the result of measuring the same tape-type optical fiber in a bundled state. In this case, since the winding direction of the tape-type optical fiber core is limited to only one direction, a result far from a true skew value is shown.

For this reason, it is necessary to measure the skew of the conventional tape-type optical fiber in a drawn state.

[0017]

However, when the skew measurement of the tape-type optical fiber is performed in a drawn state, especially when the tape-type optical fiber has a long tape length, a wide area is required for extending the tape-type optical fiber. Space is required and handling is very complicated.

An object of the present invention is to provide a skew measurement method capable of accurately measuring a skew of a multicore fiber.

Another object of the present invention is to provide a skew measurement system capable of providing a compact measurement system without taking up space in skew measurement.

[0020]

SUMMARY OF THE INVENTION The present invention relates to a measuring method for measuring the skew of a multi-core fiber wound on a bobbin, wherein at least one cylindrical member having the same radius is used as the bobbin. A winding step in which the front and back surfaces of the multi-core fiber are wound with the same number of times each facing the cylindrical surface, and the number of turns on the front and back surfaces is set to the same number of times. And a skew measuring step of measuring the skew of the skew.

The present invention relates to a measuring system for measuring a skew of a multi-core fiber wound on a bobbin, wherein at least one cylindrical member having the same radius used as the bobbin is provided on a cylindrical surface of the cylindrical member. On the other hand, a multi-core fiber whose front surface and back surface are wound opposite each other by the same number of times, and skew measurement means for measuring the skew of the multi-core fiber having the same number of turns on the front surface and the back surface A skew measurement system is provided.

According to the present invention, there is provided a fiber winding method for winding a multi-core fiber around a bobbin, wherein at least one cylindrical member having the same radius is used as the bobbin, and the bobbin is wound on a cylindrical surface of the cylindrical member. A fiber winding method is provided by providing a winding step of winding the front and back surfaces of a multi-core fiber each several times in opposition.

Here, in the winding step, the front surface and the back surface of the multi-core fiber may be wound alternately once each on the cylindrical surface of the cylindrical member.

In the winding step, the surface of the multi-core fiber is wound so as to be approximately half the entire length of the multi-core fiber, with the surface of the multi-core fiber facing the cylindrical surface of the cylindrical member. The back surface of the multi-core fiber may be opposed to a cylindrical surface, and the remaining length of the multi-core fiber may be wound by about half.

The multi-core fiber may be a tape-type optical fiber as a transmission medium for multi-channel parallel optical transmission.

[0026]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[First Example] A first embodiment of the present invention will be described with reference to FIGS. The same parts as those in the conventional example are denoted by the same reference numerals.

(Skew Measurement System) FIG. 1 shows a configuration of a skew measurement system according to the present invention.

Reference numeral 10 denotes a multi-core fiber wound in an eight-shape.

An optical component analyzer 20 measures the skew of the multicore fiber 10.

Both ends of the multi-core fiber 10 are connected to an optical connector conversion cord 31 via a multi-core connector 30. The optical connector conversion cord 31 is connected to the input / output terminal 21 of the optical component analyzer 20 via an optical connector (single core) 32 and an optical fiber cord 33.

(Configuration of Multi-core Fiber) Here, the configuration of the multi-core fiber 10 used for skew measurement will be described.

In the present embodiment, as the multi-core fiber 10, a tape-type optical fiber (hereinafter denoted by reference numeral 10) as a transmission medium for multi-channel parallel optical transmission is exemplified.

This tape-type optical fiber 10 has a plurality of optical fiber strands 2 arranged in a horizontal line, a secondary coating is applied thereto, and the tape-type optical fiber 10 is integrated in a tape shape, as in FIG. It is constituted by an optical fiber 1.

In this case, as a precondition, the optical fiber strands 2 arranged in a horizontal line are not completely aligned,
It is assumed that when viewed finely, it is irregular in the thickness direction.

The tape type optical fiber 1 comprising the optical fiber core 1 having the plurality of optical fiber strands 2
0 is at least one (here, two) bobbins 4
The optical fiber core wire 1 is wound under predetermined winding conditions with respect to a and 4b.

Here, the predetermined winding condition is defined as “the winding of the tape-type optical fiber 10 such that the front surface 10a and the rear surface 10b of the bobbin 4a, 4b have the same radius and are opposed to each other by the same number of times. "Do" is assembled as a winding condition. The bobbins 4a and 4b are made of cylindrical members having the same radius r.

(Winding method of multi-core fiber) There are various winding methods for winding the tape-type optical fiber 10 on a bobbin having the same radius under the above-mentioned predetermined winding conditions.

First, an example of winding the tape type optical fiber 10 used for skew measurement will be described with reference to FIGS.

FIG. 2 shows the winding direction in this embodiment, and is a top view schematically showing two bobbins 4a and 4b having the same radius which are placed adjacent to each other on a plane. is there.

In this case, the tape type optical fiber 10 is wound around the bobbins 4a and 4b one by one alternately in the opposite direction (A direction and B direction) of the figure eight shape. That is, the front surface 10a and the back surface 10b of the tape-type optical fiber 10 alternate with the side surfaces of the bobbins 4a and 4b by one.
Wrap it so that it is inverted every time.

FIGS. 3A to 3C show a specific winding method.

FIG. 3 (a) shows a state before winding in which bobbins 4a and 4b having the same radius r are arranged adjacently on a plane.

FIG. 3B shows a state in which the tape-type optical fiber 10 is being wound around the bobbins 4a and 4b.

In this case, first, the tape-type optical fiber 10 is wound around the side surface of the bobbin 4a with the surface 10a facing (ie, abutting or separating).

Subsequently, the back surface 10b of the tape-type optical fiber 10 is wound so as to face (ie, abut or separate from) the side surface of the bobbin 4b.

FIG. 3C shows a state after the tape-type optical fiber 10 has been wound only once around the bobbins 4a and 4b.

In this case, the front surface 10a and the back surface 1 of the tape type optical fiber 10 are
0b is wound in a state of being alternately inverted once each.

As described above, the bobbins 4a, 4b having the same radius
In contrast, the front and back surfaces of the tape-type optical fiber 10 are alternately reversed and wound by the same number of times, so that the respective directions (that is, the directions of the front surface 10a and the back surface 10b).
Skew can be offset.

As shown in FIG. 4, the bobbins 4a and 4b around which the tape type optical fiber 10 is wound may be installed vertically to prepare for skew measurement. As described above, the method of installing the bobbins 4a and 4b at the time of skew measurement is not particularly limited.

(Skew Measurement) Next, a method for measuring the skew of the tape type optical fiber 10 will be described.

The skew (ps) of the tape type optical fiber 10
/ M) are continuously distributed in the line direction and increase in proportion to the line length.

The skew is caused by each optical fiber 2 of the optical fiber 1 constituting the tape type optical fiber 10.
Is measured by measuring the light transit time difference of

In this case, the light propagation time difference can be measured by using the optical component analyzer 20 to convert the phase difference of the sine wave modulated light propagated through each optical fiber 2.

FIG. 5 shows the results of measuring the skew of the optical fiber core wire 1 of the four-fiber tape type optical fiber 10.

For the four-core tape type optical fiber 10, the same fiber and the same measurement conditions were used for comparison with the skew measurement results shown in FIGS.

Here, based on the skew measurement conditions,
The measurement result of this example in FIG. 5 is compared with the measurement result in the extended state of FIG. 11 described above and the measurement result in the winding state which is the conventional measurement method in FIG.

In the extended state of FIG. 11, a pattern in which the core number 3 is more varied than the other core numbers 1, 2, and 4 appears. Also, in the winding state of FIG.
However, a pattern that is extremely different from other core numbers 1 and 4 appears.

On the other hand, FIG. 5 of this example is significantly different from the variation pattern of FIG. 12, but it can be seen that the same variation pattern as in FIG. 11 appears.

By making a qualitative determination in this way, an accurate skew measurement result can be reproduced.

As described above, each bobbin 4 having the same radius r
The skew can be accurately measured by alternately winding the tape-type optical fiber 10 in the opposite directions (A direction and B direction) once and the same number of times for a and 4b. .

In this example, the criterion for evaluating the reproducibility of the skew measurement result is a qualitative judgment (that is, a judgment using a variation pattern formed by four cores).
However, the present invention is not limited to this, and similar results can be obtained based on quantitative determination. That is, similar results can be obtained by evaluating the reproducibility (for example, comparing FIG. 11 and FIG. 5) from the variation pattern of the individual cords.

[Second Example] A second embodiment of the present invention will be described with reference to FIGS. Note that the same reference numerals are used for the same parts as in the above-described example.

This example shows a modification of the method of winding the tape type optical fiber 10.

Hereinafter, a specific description will be given.

FIG. 6 shows an example of winding on two bobbins 4a and 4b.

First, the surface 10a of the tape type optical fiber 10 is made to face (ie, abut or separate from) the side surface of the bobbin 4a, and A
Wind in the direction.

Subsequently, the back surface 10b is opposed (ie, abuts or separates) from the side surface of the bobbin 4b by inverting the tape-type optical fiber 10 this time, and the length B of the remaining fiber is approximately half. Wind in the direction.

As described above, bobbins 4a and 4b having the same radius
In contrast, the front surface 10a and the back surface 10b of the tape-type optical fiber 10 are reversed and wound the same number of times, so that the respective directions (that is, the front surface 10a and the back surface 10b
Direction) on the skew can be offset.

Therefore, the influence on the skew can be canceled without extending the tape-type optical fiber 10, so that accurate skew measurement can be performed without taking up space.

Further, the trouble of handling the extended tape-type optical fiber 10 can be relieved. Further, since the tape-type optical fiber 10 is wound around the bobbins 4a and 4b, the tape-type optical fiber 10 is in a more stable state than the extended state.

FIG. 7 shows three bobbins 4a, 4 having the same radius.
An example of winding for b and 4c is shown.

First, the back surface 10b of the tape type optical fiber 10 is opposed to the bobbin 4a (that is, abuts or separates from the bobbin 4a), and the length of about half of the entire fiber is along the direction A, for example, 10 times. Roll up.

Subsequently, the surface 10a of the tape-type optical fiber 10 is opposed (ie, abutted or separated) to the bobbin 4b, and the remaining half of the fiber is wound five times in the opposite B direction. .

Further, the surface 10a of the tape-type optical fiber 10 is made to face (ie, abut or separate from) the bobbin 4c, and the remaining half of the tape-type optical fiber 10 faces the opposite B direction. Roll 5 times.

As a result, the tape type optical fiber 10
Since the coils are wound by the same number of times 10 times in each of the A direction and the B direction, the front surface 10 a and the back surface 1 a
The effect of 0b on the skew can be offset,
This enables accurate skew measurement as in the case of the extended state.

[Third Example] A third embodiment of the present invention will be described with reference to FIG. Note that the same reference numerals are used for the same parts as those in the above-described examples.

FIG. 8 shows an example of winding on one bobbin 4a.

First, the surface 10a of the tape type optical fiber 10 is made to face (ie, abut or separate from) the side surface of the bobbin 4a, and A
Wind in the direction.

Subsequently, with respect to the side surface of the same bobbin 4a,
By inverting the tape type optical fiber 10, the back surface 10b is opposed (that is, abuts or separates), and is wound in the same A direction by about half the length of the remaining fiber.

Thus, for one bobbin 4a,
Front surface 10a and back surface 10b of tape type optical fiber 10
Is reversed and wound the same number of times, the influence on the skew of each direction (that is, the direction of the front surface 10a and the back surface 10b) can be cancelled. Measurement can be performed.

The present invention is not limited to the above example. For example, the multi-core fiber is not limited to a tape-type optical fiber. It may be a book.

[0083]

As described above, according to the present invention,
The skew is measured using at least one bobbin of the same radius using a tape-type optical fiber whose front and back surfaces are wound the same number of times each, so that the total length of the optical fiber The effect on the skew can be offset by winding the half upside down, which allows the same accurate skew measurement as when measuring in the extended state, and saves space. , A compact skew measurement system can be manufactured.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of a skew measurement system according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a winding direction of the multi-core fiber according to the first embodiment of the present invention.

FIG. 3 shows a method of winding a multi-core fiber,
(A) is a perspective view showing the state before winding, (b) is a perspective view showing the middle of winding, and (c) is a perspective view showing the state after winding.

FIG. 4 is a perspective view showing a vertical state of the multi-core fiber.

FIG. 5 is a characteristic diagram showing a skew measurement result of the present invention.

FIG. 6 is a perspective view showing a method of winding a multi-core fiber around two bobbins according to a second embodiment of the present invention.

FIG. 7 is a perspective view showing a method of winding a multi-core fiber around three bobbins.

FIG. 8 is a perspective view showing a method of winding a multi-core fiber around one bobbin according to a third embodiment of the present invention.

FIG. 9 is a cross-sectional view showing the internal configuration of the tape-type optical fiber.

FIG. 10 is a perspective view showing a tape-type optical fiber wound by a conventional winding method.

FIG. 11 is a characteristic diagram illustrating a skew measurement result in a drawn state of the tape-type optical fiber.

FIG. 12 is a characteristic diagram showing a skew measurement result in a wound state of the tape-type optical fiber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical fiber core wire 2 Optical fiber strand 3 Bobbin 4a, 4b, 4c Bobbin 10 Tape type optical fiber 20 Optical component analyzer 30 Multi-core optical connector 31 Optical connector conversion code 32 Optical connector 33 Optical fiber code

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kosuke Katsura 3-19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Japan Telegraph and Telephone Corporation (72) Inventor Yasuhiro Ando 3-192-1, Nishishinjuku, Shinjuku-ku, Tokyo No. Nippon Telegraph and Telephone Corporation F term (reference) 2F065 AA11 BB13 BB22 CC23 DD02 FF32 LL03 PP11 PP22 2H038 AA02 CA35

Claims (12)

[Claims] 1. A measuring method for measuring a skew of a multi-core fiber wound on a bobbin, wherein at least one cylindrical member having the same radius is used as the bobbin, A winding step of winding the front and back surfaces of the multi-core fiber so as to face each other by the same number of times, and a skew measurement step of measuring the skew of the multi-core fiber having the same number of turns on the front and back surfaces A skew measurement method characterized by comprising: 2. The winding step, wherein the front surface and the back surface of the multi-core fiber are wound alternately once each on the cylindrical surface of the cylindrical member. Item 2. The skew measurement method according to item 1. 3. The winding step: winding the multi-core fiber by about half the total length of the multi-core fiber, with the surface of the multi-core fiber facing the cylindrical surface of the cylindrical member; 2. The skew measurement method according to claim 1, wherein the back surface of the multi-core fiber is opposed to the cylindrical surface of the cylindrical member, and the remaining length of the multi-core fiber is wound about half. 4. The skew measuring method according to claim 1, wherein said multi-core fiber is a tape-type optical fiber used as a transmission medium for multi-channel parallel optical transmission. 5. A measuring system for measuring a skew of a multi-core fiber wound on a bobbin, wherein at least one cylindrical member having the same radius used as the bobbin and a cylindrical surface of the cylindrical member are provided. A multi-core fiber whose front and back surfaces are wound the same number of times each, and a skew measuring means for measuring the skew of the multi-core fiber having the same number of turns on the front and back surfaces. A skew measurement system characterized by comprising: 6. The skew measurement according to claim 5, wherein the front surface and the back surface of the multi-core fiber are wound alternately once each facing the cylindrical surface of the cylindrical member. system. 7. The multi-core fiber is wound around the cylindrical surface of the cylindrical member so that the surface of the multi-core fiber is opposed to the cylindrical surface of the multi-core fiber by about half of the total length of the multi-core fiber. The skew measurement system according to claim 5, wherein the back surface of the multi-core fiber is opposed to the multi-core fiber, and the remaining half of the multi-core fiber is wound. 8. The skew measurement system according to claim 5, wherein the multi-core fiber is a tape-type optical fiber used as a transmission medium for multi-channel parallel optical transmission. 9. A fiber winding method for winding a multi-core fiber around a bobbin, wherein at least one cylindrical member having the same radius is used as the bobbin, and the multi-core fiber is wound on a cylindrical surface of the cylindrical member. A fiber winding method, comprising a winding step of winding the fiber so that the front surface and the back surface face each other the same number of times. 10. The winding step, wherein the front surface and the back surface of the multi-core fiber are wound alternately once each on the cylindrical surface of the cylindrical member. Item 10. The fiber winding method according to Item 9. 11. The winding step includes: winding the multi-core fiber by about half the total length of the multi-core fiber with the surface of the multi-core fiber facing the cylindrical surface of the cylindrical member; 10. The fiber winding method according to claim 9, wherein the back surface of the multi-core fiber is wound around a half length of the multi-core fiber with the back surface of the multi-core fiber facing the cylindrical surface of the cylindrical member. . 12. The fiber winding method according to claim 9, wherein the multi-core fiber is a tape-type optical fiber used as a transmission medium for multi-channel parallel optical transmission.