JP3461707B2 - Optical fiber identification method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber discriminating method for discriminating the type of optical fiber.

[0002]

2. Description of the Related Art For example, a so-called DSM type optical fiber (Dispersion shifted single fiber) is used.
Mode optical fiber) or so-called DSF type optical fiber (Dispersion Shifted Fiber) and SM type optical fiber can be distinguished by (1) OTDR (Optical Time Dom)
The optical fiber connected to the ain Reflectometer is connected to the optical fiber to be discriminated, and the connection loss between both optical fibers is observed by the OTDR. (2) Profile measurement by optical fiber side surface transmission image has been conventionally performed. It was Since the determination method of (2) above requires precise measurement using an expensive optical measurement system, it takes time and labor. Therefore, the determination method of (1) above is general. In the discrimination method of (1), the SM type optical fiber and the DSM type optical fiber have different connection losses when they are connected to different optical fibers, and the type is determined by measuring the connection loss. . That is, when the optical line is observed by OTDR, the connection point between the optical fibers can be confirmed by the abrupt change of the backscattered light of the test light incident on the optical line.
The type optical fiber and the DSM type optical fiber differ in the amount of backscattered light that appears at the connection point with another optical fiber, and thus the type can be determined.

[0003]

[Problems to be Solved by the Invention] However, (1)
In the determination method of (1), since it is necessary to improve the measurement accuracy of the backscattered light in the OTDR, high accuracy is required for the connection between the optical fiber on the OTDR side and the optical fiber to be determined. For this reason, the time and labor involved in aligning the optical fibers are increased, and there is a large demerit in discriminating a large number of optical fibers. Further, in order to improve the accuracy of discriminating the type of optical fiber, a high-precision optical measurement system is required, which causes a problem of high cost. Such a problem is not limited to the above-mentioned discrimination between the SM optical fiber and the DSM optical fiber, and occurs also in the discrimination of other optical fibers.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical fiber discriminating method capable of discriminating the type of an optical fiber simply and quickly.

[0005]

In order to achieve the above object, in the optical fiber discriminating method according to the present invention, a movable fiber is used.
Adjust the alignment block while it is supported by the
A first measurement step of measuring a connection loss by detachably connecting a sample optical fiber to be discriminated which is positioned by a core mechanism to a master optical fiber and sending light into the master optical fiber ;
Curved with a curved upper surface that can approach and separate
A plate and a curved lower surface corresponding to the curved plate
Providing curved plates and bringing these curved plates close to each other
By sandwiching the fiber, met connected near the distal end to the master optical fiber of the sample optical fiber
Then, by bending the light at a position deviated from the tip and sending light, the connection loss measured in the first measuring step and the bending loss due to the bending are added to the sample optical fiber. Splice loss with the master optical fiber
And a second measuring step of measuring as, determine the type of the sample optical fiber from the difference between the connection loss was measured at the first measuring step, a connection loss was measured by the second measuring step It is characterized by doing.

In this optical fiber discriminating method, the difference between the splice loss measured in the first measuring step and the splice loss measured in the second measuring step (hereinafter referred to as "bending loss") is calculated. calculate. This bending loss corresponds to an increase in optical transmission loss due to bending of the sample optical fiber. Since the bending of the sample optical fiber is near the connection point with the master optical fiber, if an optical pulse tester is used, the optical transmission loss due to the bending of the sample optical fiber is almost the same as the connection loss at the connection point. To be measured. Depending on the type of optical fiber,
For example, since the SM type optical fiber and the DSM type optical fiber have greatly different bending losses, the type of the sample optical fiber can be easily discriminated by the bending loss measured in the first and second measurement steps. . That is, DSM
The type optical fiber has a smaller core diameter than the SM type optical fiber and has a small dispersion at a specific wavelength, for example, 1.55 μm. Since the number of fibers is smaller than that of fibers, it is possible to distinguish this from the SM type optical fiber by utilizing this fact. Specifically, the bending loss of the SM optical fiber is 3.0 to 7.0 dB, while the bending loss of the DSM optical fiber is 0.2 to 0.8 dB. Therefore, it is possible to easily discriminate between the SM type and the DSM type of the sample optical fiber.

In this optical fiber discriminating method, the connection loss between the connected sample optical fiber and master optical fiber can be measured by the so-called optical power monitor method. That is, a light source is connected to one of the connected sample optical fiber and master optical fiber, an optical power meter is connected to the other, and the incident light from the light source is received by the optical power meter to measure the received light intensity. The bending loss can be calculated by measuring the splice loss with and without bending near the connection point between the sample optical fiber and the master optical fiber. The type can be determined. In this optical fiber discriminating method, the type of optical fiber can be discriminated by the equipment used for the ordinary optical line test, and there is no need to apply an especially expensive optical measuring system.

In the optical fiber discriminating method according to claim 2,
Select from a pallet that stores multiple movable fiber holders
Position the movable fiber holder of with respect to the rail,
Move the target movable fiber holder through the rail section.
Move it near the connection with the master optical fiber.
The state of being supported by the movable fiber holder for the above purpose.
Attach the sample optical fiber to the aligning mechanism of the aligning block.
After further positioning, the first measurement step and the first measurement step
The measurement step 2 is performed, and then the movable file for the above purpose is
The ball holder is returned to the pallet .

In each of the optical fiber discriminating methods of claims 1 and 2, the type of optical fiber is discriminated by utilizing the difference in optical transmission loss due to bending of the optical fiber.
The present invention is not limited to the distinction between the SM type optical fiber and the DSM type optical fiber, and can be used for determining the type of various optical fibers. In the optical fiber discriminating method according to claim 1,
By adopting a mechanism that allows the sample optical fiber to be easily attached to and detached from the master optical fiber previously connected to the optical pulse tester, connection workability can be improved, and moreover, the sample optical fiber can be connected to the master optical fiber. Since the sample optical fiber can be tested by the optical pulse tester simply by connecting the above, it is possible to efficiently discriminate a large number of optical fibers.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG.
The description will be made with reference to FIG. FIG. 1 shows an example of an optical fiber discriminating apparatus applied to this optical fiber discriminating method. In FIG. 1, the optical fiber discriminating apparatus 1 includes a master side fiber holder 2, a connecting portion 3, a rail portion 4, a bending mechanism 5, a pallet 6 and a movable fiber holder 7.

The master-side fiber holder 2 clamps the tip of the master optical fiber 9 connected to the optical pulse tester 8 (OTDR in FIG. 1) by the openable and closable lids 2a and 2b to support it at a fixed position. In the master-side fiber holder 2, the master optical fiber 9 is linearly positioned by a positioning means (not shown) such as a positioning groove. The connecting portion 3 includes two aligning blocks 3a and 3b. These alignment blocks 3a and 3b are arranged on an extension of the positioning straight line of the master optical fiber 9 by the master side fiber holder 2 and are separated from each other. In the master optical fiber 9 supported by the master-side fiber holder 2, the bare fiber 9a exposed by removing the coating at the tip is the master-side fiber holder 2
The alignment block 10a (see FIG. 2) for the alignment block 3a is positioned and aligned. The tip of the bare fiber 9a is positioned between the centering blocks 3a and 3b.

FIG. 2 is a perspective view showing the connecting portion 3. In FIG. 2, the aligning mechanism 10a of the aligning block 3a near the master-side fiber holder 2 is composed of a plurality of V-grooves 10b arranged in parallel on the upper surface of the aligning block 3a. Each of the bare fibers 9a exposed at the tip is precisely positioned by the V groove 10b. The tip of the bare fiber 9a is positioned substantially in the middle between the two aligning blocks 3a and 3b, and is butt-connected to the plurality of bare fibers 11a exposed at the tip of the sample optical fiber 11 (optical fiber ribbon). It The bare fiber 11a on the side of the sample optical fiber 11 is precisely positioned by the plurality of V-grooves 10d forming the aligning mechanism 10c of the aligning block 3b, and is on the same straight line as the bare fiber 9a. The distance between the alignment blocks 3a and 3b is very small, and the decrease in alignment accuracy due to bending of the bare fibers 9a and 11a between the alignment blocks 3a and 3b does not affect the connection loss. Is. The aligning mechanisms 10a and 10c are not limited to V-grooves, but aligning grooves such as U-grooves and square grooves, microcapillaries, and 3
It is also possible to constitute from the mechanism etc. which carry an optical fiber (bare fiber) between the above precision balls. The sample optical fiber 11 corresponds to the sample optical fiber described in claim 1 and the optical fiber described in claim 2.

The connecting section of the optical fiber discriminating apparatus is not limited to the connecting section shown in FIG. 2, but any optical fiber can be detachably connected to each other. Various configurations such as a configuration in which fibers are connected to each other can be adopted. Further, the number of cores of the optical fibers connected at the connecting portion is not limited to the four cores shown in FIG. 2, and may be any other number. In this case, it goes without saying that the number of corresponding centers of the aligning mechanism is set to be larger than the number of cores of the optical fiber. Further, the change of the number of cores of the optical fiber or the number of corresponding cores of the aligning mechanism includes a single core.

Returning to FIG. 1, the description will be continued. The rail part 4 is
It extends on the positioning straight line of the master optical fiber 9 in the master-side fiber holder 2, and extends in a direction facing the master-side fiber holder 2 via the connecting portion 3. The bending mechanism 5 is arranged in a cutout portion 4a formed in the middle of the rail portion 4. The bending mechanism 5 includes a lower clamp member 5a which is driven up and down in the cutout portion 4a.
And the lower clamp member 5 is moved horizontally.
and an upper clamp member 5b that is moved forward and backward on a. A curved plate 5c having a curved upper surface is attached to the lower clamp member 5a, and a curved plate 5 having a curved lower surface corresponding to the curved plate 5c is attached to the upper clamp member 5b.
When the upper and lower clamp members 5a and 5b are brought close to each other, the sample optical fiber 1 is placed between the curved plates 5c and 5d.
1 is sandwiched, and is bent with a bending radius of not less than the specified value (R6 or more). However, the bending loss of the sample optical fiber 11 differs depending on the bending radius. Here, the number of curved peaks is preferably three. Further, the bending mechanism 5 can release the clamp of the sample optical fiber 11 by separating the upper and lower clamp members 5a and 5b from each other. As the bending mechanism, if the configuration is such that the sample optical fiber 11 is clamped to be bent with a bending radius larger than the specified radius and the sample optical fiber 11 can be taken out when the clamp is released, the present embodiment The configuration is not limited, and various configurations can be adopted.

The pallet 6 is arranged apart from the master side fiber holder 2 and the connecting portion 3 and is connected to the end portion of the rail portion 4 opposite to the connecting portion 3 side. The pallet 6 includes a sample optical fiber 1 to be discriminated.
A plurality of movable fiber holders 7 for supporting the tip of No. 1 are accommodated in parallel.

The movable fiber holders 7 housed in the pallets 6 can be pulled out in the rail portion 4 direction. Therefore, when the pallet 6 is slid in the direction of arrow A in FIG. 1 with respect to the rail portion 4 and the target movable fiber holder 7 is positioned with respect to the rail portion 4, the target movable fiber holder pulled out from this pallet 6 is moved. 7
Can be moved to the vicinity of the connecting portion 3 via the rail portion 4. The movable fiber holder 7 is moved by the knob 12
Is engaged with the movable fiber holder.

When the movable fiber holder 7 is pulled out to the vicinity of the connecting portion 3, the sample optical fiber 11 supported by the movable fiber holder 7 is pulled out from the optical fiber array plate 6a of the pallet 6. The sample optical fiber 11 pulled out so as to be pulled by the movable fiber holder 7 moving on the rail portion 4 extends on the rail 4 and is linearly tensioned by the tension given by the tension of the movable fiber holder 7. Therefore, when the bending mechanism 5 is driven, it can be clamped and fixed, and is bent by the bending plates 5c and 5d of the bending mechanism 5. At this time, bending of the sample optical fiber 11 in a direction other than the bending by the bending plates 5c and 5d is restricted by the tension, so that the target bending radius can be reliably obtained. However, when moving the movable fiber holder 7 from the pallet 6 to the vicinity of the connecting portion 3, the bending mechanism 5 separates the clamp members 5a and 5b on the upper and lower sides so that the movable fiber holder 7 moves toward the connecting portion 3. Let it pass. Moreover, at this time, the auxiliary rails 5e and 5e formed on the lower clamp member 5a are positioned on the rail portion 4 so that the rail portion 4 is continuous so that the movable fiber holder 7 can pass freely.

The movable fiber holder 7 clamps and supports the sample optical fiber 11 by means of openable and closable magnet fixed lids 7a and 7b. Therefore, the lid 7
By opening and closing a and 7b, the sample optical fiber 11 that is clamp-supported can be easily replaced. In this movable fiber holder 7, the sample optical fiber 11 is clamped and supported so that its tip projects toward the connecting portion 3 side. Then, when the movable fiber holder 7 is moved to the vicinity of the connecting portion 3 via the rail portion 4, the plurality of bare fibers 11a exposed at the tip of the sample optical fiber 11 are aligned with each other. The centering mechanism 1 is inserted into the centering mechanism 10c of the block 3b and precisely positioned, and the centering mechanism 1
The bare fiber 9 of the master optical fiber 9 is penetrated through 0c.
butt-connected with a. Conversely, when the movable fiber holder 7 is returned to the pallet 6 direction, the bare fiber 11a is pulled out from the aligning mechanism 10c, and the connection state of the master optical fiber 9 with the bare fiber 9a is released. A refractive index matching agent is preferably applied to the tip of the bare fiber 9a of the master optical fiber 9 and the tip of the bare fiber 11a of the sample optical fiber 11 in order to improve measurement accuracy and reduce Fresnel reflection.

In this optical fiber discriminating apparatus 1, when the connection state between the sample optical fiber 11 and the master optical fiber 9 is maintained and the test light is sent from the optical pulse tester 8, the connection between the optical fibers 11 and 9 is made. The loss can be measured.
Further, the bending mechanism 5 is driven to drive the upper and lower clamp members 5a,
When the sample optical fiber 11 is sandwiched between 5b and the bending is applied and the test light is sent from the optical pulse tester 8, both the optical fibers 11 including the optical transmission loss due to the bending of the sample optical fiber 11 are included. , 9 can be measured.

When the movable fiber holder 7 is returned to the pallet 6 and another movable fiber holder 7 is pulled out and moved to the vicinity of the connecting portion 3, the bare fiber 11a of the sample optical fiber 11 supported by the movable fiber holder 7 is aligned. 10
It is inserted into c, positioned, and connected to the bare fiber 9a on the master optical fiber 9 side. In this way, the movable fiber holder 7 is sequentially pulled out, and the master optical fiber 9
When the sample optical fiber 11 to be connected to is exchanged, the connection loss between the sample optical fiber 11 and the master optical fiber 9 is increased for a large number of sample optical fibers 11 when the sample optical fiber 11 is not bent and when it is bent. For both cases,
It is possible to measure sequentially and efficiently.

The connection loss is measured by the optical pulse tester 8 for each optical line formed by connecting the bare fibers 9a and 11a (the bare fiber 11 for the sample optical fiber 11).
a)), it is possible to measure the connection loss for a plurality of bare fibers 11a by a single connection work by connecting the multi-core optical fibers 9 and 11 to each other.
It reduces the number of connections. Further, by connecting a plurality of single-core optical fibers to the multi-core master optical fiber 9, it is possible to efficiently measure the connection loss for the plurality of single-core optical fibers.

Next, an embodiment in which the optical fiber discriminating method of the present invention is applied to the optical fiber discriminating apparatus 1 will be described.
Sample optical fiber 11 using the optical fiber discriminating apparatus 1
In order to determine the type of the sample optical fiber 11, first, the movable fiber holder 7 is moved to the vicinity of the connecting portion 3 and the connection loss between the master optical fiber 9 and the sample optical fiber 11 to be discriminated, which are connected to each other, is calculated. The measurement is performed by the optical pulse tester 8 when no bending is applied to (1st measurement step). Next, the bending mechanism 5 is driven to bend the sample optical fiber 11 in the vicinity of the tip connected to the master optical fiber 9 to reduce the connection loss between the sample optical fiber 11 and the master optical fiber 9. Measure (second measuring step). Next, the difference between the splice loss (measurement value A) measured in the first measurement step and the splice loss (measurement value B) measured in the second measurement step, that is, the bending loss is obtained. The bending loss is calculated by the following equation. Bending loss = measured value B-measured value A

In this optical fiber discriminating method, the type of the sample optical fiber 11 can be easily discriminated based on the calculated bending loss value. For example, when the bending loss is 3.0 to 7.0 dB with pulsed light having a wavelength of 1.55 μm, the SM
A type optical fiber and a bending loss of 0.2 to 0.8 dB are said to be a DSM type optical fiber, so that the type of optical fiber can be clearly discriminated by comparing the values of bending loss.

The measurement of the connection loss carried out by the optical fiber discriminating method of the present invention is not limited to the one using the optical pulse tester 8 and can also be carried out by the optical power monitor method. In this case, one of the light source and the optical power meter is connected to the master optical fiber 9 and the other is connected to the sample optical fiber 11. If the detachability of the sample optical fiber 11 with respect to the light source or the optical power meter can be secured,
It is possible to secure the work efficiency of measuring the connection loss and the workability of the optical fiber discrimination. In addition, this optical fiber discrimination method,
It can also be used for determination of various types of core wires other than the SM type optical fiber and the DSM type optical fiber.

[0025]

According to the optical fiber discriminating method of the present invention, the connection loss between the master optical fiber and the sample optical fiber to be discriminated is determined when the sample optical fiber is not bent, and Near the tip of the sample optical fiber connected to the master optical fiber, and shifted from the tip
Since the measurement was performed when the position was bent, and the type of the sample optical fiber was discriminated from the difference (bending loss) in the measured splice loss, (a) the splice loss between the master optical fiber and The type of sample optical fiber can be discriminated more easily and easily than the conventional discriminating method for discriminating the type of sample optical fiber from the size. (B) Optical pulse tester or light used for optical pulse test The type of sample optical fiber can be discriminated by measuring the splice loss using a power meter, etc., and no special high-precision measuring device is required, so the discrimination workability can be improved and the discrimination cost can be reduced. It has an excellent effect.

[0026]

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention and is a perspective view showing an optical fiber discriminating apparatus.

FIG. 2 is an enlarged perspective view showing the vicinity of a connecting portion of the optical fiber discriminating apparatus of FIG.

[Explanation of symbols]

9 ... Master optical fiber, 11 ... Sample optical fiber.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Horikoshi 1440 Rokuzaki, Sakura-shi, Chiba Fujikura Co., Ltd. Sakura factory (72) Inventor Sanchiro Oi 1-840 Mitsuhashi, Omiya-shi, Saitama Fujikura Rubber Industrial Co., Ltd. Omiya Factory (72) Inventor Shigeru Emori 1440 Rokuzaki, Sakura City, Chiba Fujikura Co., Ltd.Sakura Factory (72) Inventor Koji Saito 1440 Rokuzaki, Sakura City, Chiba Fujikura Co., Ltd. (72) Invention Person Koji Mori 1440 Rokuzaki, Sakura City, Chiba Prefecture Fujikura Ltd. Sakura Factory (56) References JP-A-54-78157 (JP, A) JP-A-2002-365161 (JP, A) (58) Fields investigated (58) Int.Cl. ⁷ , DB name) G01M 11/00-11/08 H04B 9/00 H04B 17/00-17/02

Claims (2)

(57) [Claims] 1. Supported by a movable fiber holder (7).
The alignment block (3b), the alignment mechanism (10
First, a splicing loss is measured by detachably connecting a sample optical fiber (11) to be discriminated to be positioned by c) to a master optical fiber (9) so as to send light.
Plate with a curved upper surface that can be approached and separated from the measurement process of
(5c), and the curved lower surface corresponding to the curved plate,
A curved plate (5d) that has
By sandwiching the sample optical fiber by, a said master light connected near the distal end to the fiber of the sample optical fiber, by fed light by adding bending at a position shifted a tip, wherein Measured by the first measurement process
If the bending loss due to the bending is added to the specified connection loss ,
And a second measurement step of measuring as a connection loss between the sample optical fiber and the master optical fiber, the connection loss measured in the first measurement step, and the second
The optical fiber discriminating method, wherein the type of the sample optical fiber is discriminated from the difference with the connection loss measured in the measuring step. 2. A pallet for accommodating a plurality of movable fiber holders.
Put the target movable fiber holder on the rail (6).
Positioning with respect to (4), the movable fiber ho
Route the master optical fiber through the rail section.
Move it to the vicinity of the connection with the
Align the sample optical fiber supported by the holder with the
After positioning by the aligning mechanism of the block,
1 measurement step and the second measurement step are performed, and
Then, return the target movable fiber holder to the pallet.
Optical fiber determination method according to claim 1, characterized in that to.