JP7262542B2 - Core matching method and cable gripper - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act Published on October 1, 2020 in NTT Technical Journal, 2. Release date October 29, 2020, October 30, 2020 At Tsukuba Forum 2020 ONLINE, 3. Date of issue January 1, 2021 Business Communication 4. Release date January 18 to January 22, 2021 at NTT East Solution Forum 2021 ONLINE, 5. Date of publication February 23, 2021 In Proceedings of Correspondence Lecture 2 of the 2021 General Conference of the Institute of Electronics, Information and Communication Engineers, 6. Publication date March 9th to March 12th, 2021 At the 2021 IEICE general meeting, "Method for comparing fiber cores and cable gripper" was published.

The present invention relates to a wire matching method and a cable gripper.

An optical fiber is laid between communication devices in a communication facility building. During maintenance and operation of optical fibers, it is necessary to specify the optical fiber core wire to be worked on. Specifically, a reference light source is connected to one end of the optical fiber core wire, and intensity-modulated reference light is incident on the optical fiber core wire. At the work site, the optical fiber core wire is grasped by the fiber detector and the presence or absence of reference light is detected to confirm that it is the optical fiber core wire to be worked on.

JP 2020-170949 A

The core detector creates a bend in the optical fiber core and detects control light leaking from the bend. A single-mode optical fiber can obtain leakage light by bending, but a graded index (GI) multimode optical fiber has a small leakage light intensity even if it is bent in the same way as a single-mode optical fiber. It was difficult to detect the leaked light with the core detector.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to enable alignment of GI multimode optical fibers.

A fiber aligning method of one aspect of the present invention is a fiber aligning method for a multimode optical fiber, comprising the step of: injecting intensity-modulated contrast light into the multimode optical fiber; The method includes a step of applying a plurality of continuous bends to a multimode optical fiber to generate higher-order modes in the reference light, and a step of detecting the presence or absence of the reference light with the core optical detector.

A cable gripping tool according to one aspect of the present invention is a cable gripping tool that continuously bends a multimode optical fiber when performing core alignment of the multimode optical fiber, wherein peaks and valleys are alternately arranged. and a second bent portion in which crests and troughs that mesh with the crests and troughs of the first bent portion are arranged alternately. By gripping the multimode optical fiber by engaging the first bent portion and the second bent portion from the side of the multimode optical fiber, a plurality of continuous bends are applied to the multimode optical fiber. A high-order mode is generated in the reference light incident on the optical fiber, and the peaks and valleys of the first bent portion and the second bent portion form the core-line contrast when the multimode optical fiber is held. The shape is such that the leakage light intensity of the reference light in the device is increased to 15 dB or more, and the loss of the communication light is suppressed to 1 dB or less .

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to align GI-type multimode optical fibers.

FIG. 1 is a diagram showing an example of how the cardiogram contrast method of this embodiment is carried out. FIG. 2 is a diagram showing an example of how a higher-order mode is generated in the reference light by giving a plurality of continuous bends to the optical fiber core wire. FIG. 3 is a diagram showing an example of a screw-type cable gripper. FIG. 4 is a diagram showing an example of use of a screw-type cable gripper. FIG. 5 is a diagram showing an example of a clip-type cable gripper. FIG. 6 is a diagram showing an example of a fixing member that fixes the cable gripper. FIG. 7 is a diagram showing a usage example of a clip-type cable gripper. FIG. 8 is a diagram showing an example of a tongue-type cable gripper. FIG. 9 is a diagram showing an example of a push-type cable gripper. FIG. 10 is a diagram showing an example of use of a push-type cable gripper.

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

FIG. 1 is a diagram showing an example of how the cardiogram contrast method of this embodiment is carried out. In the fiber contrast method shown in FIG. 1, a contrast light source 20 is connected to the connector of the optical fiber core 100 and contrast light is incident on the optical fiber core 100 . The contrast light source 20 outputs intensity-modulated contrast light at a predetermined frequency. The wavelength of the control light is 1310 nm, 1550 nm, or 1625 nm.

At the work site, the optical fiber core 100 to be checked is grasped by the fiber comparator 30 and the reference light is detected. The fiber collator 30 has a bending mechanism that bends the optical fiber core 100 . The core detector 30 measures and displays the intensity of the reference light leaking from the bent portion. If the intensity of the control light is greater than or equal to the threshold, it is determined to be detected, and if the intensity of the control light is less than the threshold, it is determined to be no signal. The optical fiber core wire for which the reference light can be detected by the fiber detector 30 is the core wire to be worked on.

When the optical fiber core wire 100 is a GI-type multimode optical fiber, even if the optical fiber core wire 100 is bent by the fiber collator 30 to the same degree as a single mode optical fiber, the leakage light intensity is small. In the optical fiber comparison method of the present embodiment, the cable gripper 10 grips the optical fiber 100 in front of the fiber comparison device 30 (on the comparison light source 20 side).

The cable gripper 10 has bends 11 and 12 in which crests and troughs are arranged alternately. By gripping the optical fiber 100 from the side of the optical fiber 100 by engaging the peaks and valleys of the bent portions 11 and 12, the optical fiber 100 is continuously bent.

As shown in the image on the left side of FIG. 2, the reference light output from the reference light source 20 is focused on the center of the core, so that even if the optical fiber core 100 is bent by the optical fiber comparator 30, the contrast light is concentrated. Light does not leak easily. By sandwiching and holding the optical fiber 100 with the cable gripper 10 and giving a plurality of continuous bends to the optical fiber 100, the contrast light becomes a higher-order mode as shown in the image on the right side of FIG. , and the contrast light leaking when the optical fiber core 100 is bent by the core detector 30 can be increased. As a result, the contrast light can be easily detected by the core contrast device 30 .

The cable gripping tool 10 is required to increase the leaked light intensity to a value that can be detected by the fiber detector 30 and not to affect communication when the current fiber is erroneously gripped. Furthermore, the cable gripper 10 is required to be usable in a narrow space. The number of bends (number of crests) and curvature are determined to meet these requirements.

Table 1 shows the results of measuring the amount of improvement in leakage light intensity and the loss value of communication light by changing the number of times of bending and curvature. The values in parentheses are loss values of communication light (850 nm). The wavelength of the reference light was 1550 nm.

As shown in Table 1, when the curvature is 5 mm, the leaked light intensity of the reference light increases to 15 dB or more, while the loss of the communication light increases to 1 dB or more. On the other hand, when the curvature is 20 mm, the loss of communication light can be suppressed, but sufficient leakage light intensity cannot be obtained. By setting the curvature to 10 mm and the number of bends to 4 to 8, the leakage light intensity of the reference light can be increased to 15 dB or more and the loss of the communication light can be suppressed to 1 dB or less.

Several forms of the cable gripper 10 will now be described.

3(a) is a front view of the bent portions 11 and 12 of the cable gripper 10 of the first embodiment, and FIG. 3(b) is a side view of the bent portions 11 and 12. FIG. FIG. 4 is a diagram showing an example of use in which the cable gripper 10 of the first embodiment grips the optical fiber core 100. As shown in FIG.

Each of the bends 11, 12 has crests 11A, 12A and valleys 11B, 12B arranged alternately. The cross-sectional shape of the peaks 11A and 12A may be rectangular, semicircular, or pointed. The shape of the bottom of the cross section of the valleys 11B and 12B may be straight or curved. The peaks 11A and 12A and the valleys 11B and 12B may have any shape as long as the optical fiber cable 100 can be bent with a desired curvature when the optical fiber cable 100 is sandwiched between the peaks 11A and 12A and the valleys 11B and 12B. Further, the peaks 11A and 12A may be provided with guide grooves for the optical fiber core wire 100. FIG. The same applies to cable grippers 10 of other forms described below.

The bend 11 has a screw hole 14 and the bend 12 has a screw 13 . When the screw 13 is passed through the screw hole 14, the peaks 11A, 12A and the valleys 11B, 12B are engaged with each other.

When the optical fiber core wire 100 is gripped by the cable gripper 10, the optical fiber core wire 100 is placed on the plurality of ridges 12A in front of or behind the screw 13 of the bending portion 12. As shown in FIG. When the peak 12A has a guide groove, the optical fiber core 100 is arranged along the guide groove. The screw 13 is passed through the screw hole 14 of the bent portion 11, and the peaks 11A, 12A and the valleys 11B, 12B are engaged with each other to grip the optical fiber 100. FIG. Then, a nut 15 is attached to the screw 13 to fix the bent portions 11 and 12 . Thereby, the optical fiber core wire 100 is given a plurality of continuous bends.

After gripping the optical fiber 100 with the cable gripper 10, the operator does not need to hold the cable gripper 10 and can operate the fiber comparer 30 with both hands to carry out the work.

FIG. 5(a) is a front view of the bent portions 11 and 12 of the cable gripper 10 of the second embodiment, and FIG. 5(b) is a side view of the bent portions 11 and 12. FIG. FIG. 6 is a diagram showing an example of a fixing member 16 for fixing the bent portions 11 and 12. As shown in FIG. FIG. 7 is a diagram showing an example of use in which the cable gripper 10 of the second embodiment grips the optical fiber cable 100. As shown in FIG.

Each of the bends 11, 12 has crests 11A, 12A and valleys 11B, 12B arranged alternately.

The bent portions 11, 12 have grooves 11C, 12C for mounting the fixing member 16 of FIG. The fixing member 16 has protrusions 16A and 16B that are fitted into the grooves 11C and 12C. The shape of the fixing member 16 does not matter as long as the bent portions 11 and 12 can be fixed while the optical fiber core 100 is held. For example, the bent portions 11 and 12 may be fixed with a belt.

When the optical fiber core wire 100 is gripped by the cable gripper 10, the optical fiber core wire 100 is sandwiched between the bent portions 11 and 12, and the peaks 11A and 12A and the valleys 11B and 12B are engaged to grip the optical fiber core wire 100. do. The fixing member 16 is attached to the bent portions 11 and 12 while the optical fiber core wire 100 is held, and the bent portions 11 and 12 are fixed.

After gripping the optical fiber 100 with the cable gripper 10, the operator does not need to hold the cable gripper 10 and can operate the fiber comparer 30 with both hands to carry out the work.

FIG. 8 is a diagram showing an example of the cable gripper 10 of the third embodiment. The cable gripper 10 of the third embodiment is a tongue-type cable gripper 10 having bent portions 11 and 12 at the ends of the tongues.

Peaks 11A and 12A and valleys 11B and 12B are alternately arranged in each of the bent portions 11 and 12 . The bent portions 11 and 12 are connected by an elastic member 17 so that the peaks 11A and 12A and the valleys 11B and 12B engage with each other when a force is applied to bring them closer together. The bends 11 , 12 are spaced apart without exerting any force on the cable gripper 10 .

When gripping the optical fiber core wire 100, the optical fiber core wire 100 is arranged between the bent portions 11 and 12 along the direction in which the peaks 11A and 12A and the valleys 11B and 12B are arranged, and the peaks 11A and 12A and the valleys are aligned. The optical fiber core wire 100 is gripped by applying force to the bent portions 11 and 12 so that the bent portions 11B and 12B are engaged with each other.

In the cable gripper 10 of FIG. 8, the ends in the direction in which the peaks 11A, 12A and the valleys 11B, 12B of the bent portions 11, 12 are arranged are connected by the elastic member 17, but the peaks 11A, 12A and the valleys 11B, 12B 8, that is, the front side or the back side in FIG.

FIG. 9(a) is a front view of the cable gripper 10 of the fourth embodiment, and FIG. 9(b) is a side view of the cable gripper 10. FIG. FIG. 10 is a diagram showing an example of use in which an optical fiber cable 100 is gripped by the cable gripper 10 of the fourth embodiment. In the cable gripper 10 of the fourth embodiment, the bent portions 11 and 12 are fixed with a predetermined spacing therebetween. It is a push-type cable gripper 10 that grips the .

The crests 11A, 12A and the valleys 11B, 12B of the bent portions 11, 12 are engaged with each other, and the cross-sectional ends of the crests 11A, 12A and the valleys 11B, 12B are connected by a connecting member 18 and fixed. In the fourth embodiment, unlike the third embodiment, even if force is applied, the distance between the bent portions 11 and 12 does not change significantly.

The peaks 11A and 12A are tapered, and gradually increase in height from the opening surface (the front side in FIG. 9A and the left side in FIG. 9B) toward the back. By pushing the optical fiber core wire 100 into the cable gripper 10 from the opening surface, the optical fiber core wire 100 can be given a plurality of continuous bends.

As described above, the optical fiber comparison method of the present embodiment is such that intensity-modulated reference light is incident on the optical fiber 100 from the reference light source 20, and a continuous plurality of is applied to generate a high-order mode in the reference light, and the presence or absence of the reference light leaking from the optical fiber core 100 is detected by the optical fiber comparator 30 . This enables alignment of the GI multimode optical fiber in the alignment device.

The cable gripper 10 of this embodiment includes a bending portion 11 in which peaks 11A and valleys 11B are alternately arranged, and a bending portion in which peaks 12A and valleys 12B that mesh with the peaks 11A and valleys 11B of the bending portion 11 are alternately arranged. 12. By gripping the optical fiber 100 by engaging the bending portions 11 and 12 from the sides of the optical fiber 100, the optical fiber 100 is continuously bent. As a result, a higher-order mode can be generated in the contrast light incident on the optical fiber core 100, and the core contrast of the GI-type multimode optical fiber can be performed by the core contraster.

REFERENCE SIGNS LIST 10 cable gripper 11, 12 bending portion 20 control light source 30 fiber contrast device

Claims (6)

A method for core alignment of a multimode optical fiber, comprising:
injecting intensity-modulated contrast light into the multimode optical fiber;
giving a plurality of successive bends to the multimode optical fiber in the preceding stage of the optical fiber comparator to generate higher-order modes in the reference light;
A fiber contrast method, comprising the step of detecting the presence or absence of the contrast light in the fiber contrast device. A cable gripper that provides continuous bending to the multimode optical fiber when performing fiber alignment of the multimode optical fiber,
a first bend having alternating peaks and valleys;
A second bending portion in which peaks and valleys that mesh with the peaks and valleys of the first bending portion are arranged alternately,
The multimode optical fiber is gripped by engaging the first bent portion and the second bent portion from the side of the multimode optical fiber at the front stage of the optical fiber matcher, thereby holding the multimode optical fiber. giving a plurality of successive bends to generate higher-order modes in the reference light incident on the multimode optical fiber ;
The crests and troughs of the first bent portion and the second bent portion increase the leakage light intensity of the reference light in the optical fiber optical fiber to 15 dB or more when the multimode optical fiber is gripped, thereby enabling communication. It is a shape that suppresses the loss of light to 1 dB or less.
cable gripper. A cable gripper according to claim 2,
the first bent portion comprises a screw hole;
the second bend comprises a screw;
A cable gripping tool that fixes the first bent portion and the second bent portion by inserting the screw into the screw hole when gripping the multimode optical fiber. A cable gripper according to claim 2,
A cable gripping tool comprising a fixing member that grips the first bent portion and the second bent portion while the multimode optical fiber is gripped by the first bent portion and the second bent portion. . A cable gripper according to claim 2,
A cable gripper in which the first bent portion and the second bent portion are connected by an elastic member. A cable gripper according to claim 2,
The first bent portion and the second bent portion are fixed to each other with a predetermined gap, and the peaks and valleys are engaged with each other,
A cable gripping tool for gripping the multimode optical fiber by pressing the multimode optical fiber from the side surfaces where the peaks and valleys of the first bending portion and the second bending portion are exposed.

Images