JP2533429B2 - Optical fiber cable light guide inspection method and apparatus - 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 cable having a relatively short distance, which is employed in a management system of a factory or a building, buried or laid, and then the optical fiber of the optical fiber cable is broken. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide inspection method and apparatus for inspecting whether there is any.

[0002]

2. Description of the Related Art In a place that is easily affected by electromagnetic interference in the management of factories and buildings, an optical fiber cable is buried (or laid) in the soil in order to reliably transmit various information necessary for the management. ) May be.

The optical fiber cable buried in the soil may be crushed by the passage of a bulltozer or the like at the time of construction and part of the cable may be broken. Therefore, it is necessary to inspect whether or not all the optical fiber core wires of the optical fiber cable are disconnected after being buried. Then, the position of the disconnection is specified, the defective portion is cut, and a new optical fiber cable is connected.

Here, the optical fiber cable is a cable housing a large number of optical fiber core wires, and an example thereof will be described with reference to FIG. In FIG. 3, the tension member 22 is located at the center of the optical fiber cable 21 and bears most of the installation tension. A large number of optical fiber core wires 23 are arranged around the tension member 22 via an interposition 24 so as to have a circular cross section. The outer circumference of the optical fiber core wire 23 is covered with a sheath 25. In addition, when embedding in the soil, it is common to provide a corrugated steel pipe exterior on the outer periphery of the sheath 25. Further, there are various forms of the arrangement of the optical fiber core wires 23, and the number of the optical fiber core wires 23 to be accommodated is also one or more.

As shown in FIG. 4, the optical fiber core wire 2
Reference numeral 3 denotes an optical fiber element wire 28 composed of a core 26 and a clad 27, on the outer periphery of which a buffer layer 29 of silicon resin or the like and a secondary coating 30 of nylon or the like are applied. It is the portion of the core 26 that actually transmits light, and the GI type has a diameter of 50 μm. The entire optical fiber element wire 28 has a diameter of 125 μm, which is extremely thin.

A special device is used for the light guide inspection of the optical fiber cable having such a structure. A conventional light guide inspection device will be described with reference to FIG. The pulse light source 31 and the connector 32 holding the optical fiber strand 28 are connected to each other by a directional coupler 33.
Connect through. The photodetector 34 and the synchroscope 35 are connected to the directional coupler 33. A light pulse from a laser is incident on the optical fiber strand 28, the presence or absence of disconnection is detected by the pulse reflected from the disconnection point 28a, and the distance to the disconnection point 28a is obtained from the propagation time difference between the reflected pulse and the incident pulse. is there.

[0007]

When measuring with the above-described light guide inspection device, the sheath of the optical fiber cable is removed by a certain length to separate the optical fiber core wires, and the so-called secondary coating of the optical fiber core wires is also removed. It is necessary to carry out a light guide inspection after stripping to make the optical fiber strands and attaching the connector 32 for each optical fiber strand. As described above, the optical fiber has a diameter of 125 μm, which is extremely thin, and there is a problem in that the peeling work and the connector attaching work require skill and time. Further, the above-described light guide inspection device is made on the assumption of an optical fiber communication network having a considerable distance, and the unit is several hundreds to several kilometers as in a factory management system or a building management system. There is also a problem that the specifications are excessive when the disconnection point can be estimated from the history.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to break an optical fiber cable of a relatively short distance.
An object of the present invention is to provide a light guide inspection method and an apparatus therefor that can easily and quickly perform measurement without peeling.

[0009]

In order to achieve the above-mentioned object, the light guide inspection method of the present invention has a structure in which one end of the optical fiber cable having one or more optical fiber cores is visible at one end. optical fiber to check whether the emitters are opposed to through the visible light across the optical fiber, the optical fiber does not emit light by visually section of the other end for emitting the light beam
In the cable light guide inspection method, the light emitter is a light source.
And the bundle fiber and the end face of the bundle fiber as the light source
It is formed with a box body that is fixed facing each other.
There is a divergent conical hole starting from it at one end of the iva
Connector, and attach one end of the optical fiber cable.
By inserting the straight section into the large diameter side of the connector,
The visible light is made to face the end face of the bundle fiber.
From the light source through the bundle fiber and the connector
And collectively enter the optical fiber core wire.
Is the method.

A light guide inspection apparatus therefor is provided for both optical fiber cables having one or more optical fiber cores.
Of the end cross section, the light emitter that emits visible light is opposed to the one end cross section through the connector, the visible light is passed through the entire optical fiber core, and the other end cross section Light guide inspection of optical fiber cable
In the inspection device, the light emitter is a bundle fiber,
A light source provided at the other end of the bundle fiber and the bundle
A box body that fixes the other end of the fiber by facing the light source
And the connector has one end of the bundle fiber.
It has a conical hole with a diverging end that starts from the
The vertical cross section of the optical fiber cable is designed to be insertable.
The device is characterized in that

[0011]

[Function] By passing visible light through the optical fiber cable,
This enables visual inspection by humans, which is impossible with ordinary laser light. The presence or absence of disconnection is inspected by the advanced identification function of human eyes, and the disconnection location is specified by construction history or the like. Visible light comes from the light source, bundle fiber and connector
Are collectively injected into the optical fiber cable via
However, the bundle fiber is a straight line of uncoated optical fiber.
High efficiency of optical coupling with the light source because it is closely focused
And has good flexibility.

As a device for transmitting visible light through the entire optical fiber cable, a light emitter and a connector are used to improve the efficiency and workability of optical coupling. In particular, bundle fiber and optical fiber
The Iva cable starts at one end of the bundle fiber.
On the large diameter side of the connector that has a conical hole
The optical fiber is connected by simply inserting the IVA cable.
It can be applied even if the fiber cable diameter is slightly different.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of the method and apparatus of the present invention. First, the apparatus of the present invention will be described with reference to FIG. 1, and then the method of the present invention will be described.

In FIG. 1, the light guide inspection device comprises a bundle fiber 2, a light source 4 at the other end of the bundle fiber 2,
It is composed of a light emitter 1 whose main part is a box 5 for fixing the other end of the bundle fiber 2 and a light source 4 to face each other, and a connector 3 at one end of the bundle fiber 2. In addition, 2
Reference numeral 1 is an optical fiber cable to be inspected.

As shown in FIG. 2, the bundle fiber 2 is a bundle of a large number of multi-component glass optical fiber wires 15. Each optical fiber element wire 15 is not coated, and is directly focused to increase the density, and the outer periphery of the focused optical fiber element wire 15 is collectively covered and protected. It is preferable to use a skin layer clad 15b in which the diameter D2 of the clad 15b is smaller than the diameter D1 of the core 15a and to increase the ratio of the core 15a to the total cross-sectional area. The part of the core 15a is distributed throughout,
Light can be easily coupled, and visible light can be sent from the lamp. With a single optical fiber strand, light is emitted to the core around 50 μm at an angle smaller than the light receiving angle.
Although it is necessary to use a high-intensity laser beam and a complicated optical lens, the bundle fiber 2 eliminates such a restriction. The bundle fiber 2 is flexible and easy to handle.

One end of the bundle fiber 2 has a vertical cross section 2a.
And is fixed in the connector 3 as a connector. The connector 3 has a divergent conical hole 3a starting from the vertical cross section 2a, and a vertical cross section 21b at one end of the optical fiber cable 21 is inserted into this conical hole 3a so that both end faces thereof face each other. Even if the diameter of the optical fiber cable 21 is different, only the distance L is changed, and it is not necessary to replace the metal fitting each time, and the workability is improved. However, a certain distance L is ensured for the incidence of light from the bundle fiber 2 to the optical fiber cable 21. If the specific output angle from the bundle fiber 2 and the incident angle to the optical fiber cable 21 are matched, the coupling efficiency becomes higher.

The other end of the bundle fiber 2 also has a vertical cross section 2b.
And is fixed to the box body 5. A light source 4 such as a halogen lamp or a xenon lamp is arranged in the box body 5 so as to face the vertical cross section 2b, and the bundle fiber 2 emits visible light with a heat ray removed through a filter 6. Reference numeral 7 is a reflecting mirror of the light source 4. The light source 4 has only to emit light to the entire vertical cross section 2b of the bundle fiber 2 and is a simple light source device. Further, a storage battery is built in as a power source of the light source 4 or can be connected to a nearby 100-volt power source.

Next, a light guide inspection method using the above-described light guide inspection apparatus will be described below. Optical fiber cable 21
It is assumed that the burial in 16 of the soil has been completed and the inspection is ready. One inspector 8 holds the light emitter 1 with the connector 3 and the transceiver 9 and heads to the exposed position of the vertical cross section 21b at one end of the optical fiber cable 21. Then, one end of the bundle fiber 2 is inserted into the connector 3 to face the vertical cross section 2a at one end of the bundle fiber 2. On the other hand, another inspector 10 holds the transceiver 9 and heads to the exposed location of the vertical cross section 21c at the other end of the optical fiber cable 21. Then, the two inspectors 8 and 10 communicate with each other, and when one inspector turns on the light emitter 1 and passes visible light through the optical fiber cable 21, the other inspector examines the vertical cross section 21c of the optical fiber cable 21. If all eyes of the optical fiber are shining, the light guide is confirmed. Then, both inspectors 8 and 10 communicate with each other and move to the next inspection target. If there is even one optical fiber core wire that does not shine in the vertical cross section 21c of the optical fiber cable 21, it is determined that a wire break has occurred. In this case, the construction history of the buried route of the optical fiber cable is confirmed, for example, the place where the bulltozer runs is dug back, the collapsed portion of the optical fiber cable is found, that portion is cut, and a new optical fiber cable is connected.

In the above-described light guide inspection device, the light source using a light source such as a halogen lamp or a xenon lamp has been described. However, since these light sources require a stable and high voltage power source, The whole is large and not suitable for carrying. Therefore, a device using a visible light semiconductor laser as a light emitting device which is small and easy to handle will be described with reference to FIG.

In FIG. 5, 50 is a light emitter and 51 is a connector. The light emitter 50 includes a cylindrical body 52, an AA alkaline battery 53, a visible light semiconductor laser 54, and an aspherical lens 55.
It is a pocket size as a whole. A switch 56 is provided in the middle of the tubular body 52, and the male screw 57 at the tip of the tubular body 52 is connected to the connector 51.
Is screwed so that it can be replaced. In general, a semiconductor laser is one in which the laser medium is made of a semiconductor, and it is high in brightness despite its small size and small driving power. The visible light semiconductor laser 54, which has been developed especially for outdoor use, can be used because emission wavelengths ranging from visible to infrared can be obtained by a selected combination of semiconductor materials used. Visible light from the visible light semiconductor laser 54 is converted into substantially parallel light by the aspherical lens 55 and emitted from the tip of the cylindrical body 52. Since the light from the laser 54 is visible light, the core wire 2 of the optical fiber cable 21
The light emitted from the other vertical section 21c after being incident on the vertical section 21b including 3 can be directly confirmed by human eyes.

The vertical cross section 21b of the optical fiber cable 21 can be directly opposed to the tip of the light emitter 51, but the connector 51 is used to make visible light efficiently enter the core wire 23 of the optical fiber cable 21. . The connector 51 has a communication hole 58 having a female thread at the end and a large diameter hole 60. One end of the optical fiber cable 21 is inserted into the large diameter hole 60, and the vertical cross section 21 including the core wire 23.
b is inserted into the communication hole 58. When the diameter of the optical fiber cable 21 is different, the connector corresponding to the size of the optical fiber cable 21 is replaced. In addition, the vertical cross section 21b is formed as the entire cable 21 without projecting the portion of the core wire 23 of the optical fiber cable 21,
It can also be inserted into the large diameter hole 60.

The light emitter 50 using the visible light semiconductor laser 54 described above is small and easy to handle. Therefore,
An optical fiber cable 21 having a relatively small number of optical fiber cores, the installation of which is outdoors in the soil or the like, where the power cord is not nearby, the work environment is poor, and it is susceptible to weather such as rainfall. The light guide inspection device is suitable for the light guide inspection.

[0023]

According to the light guide inspection method of the present invention, the optical fiber core is arranged such that one end of a cross section of an optical fiber cable having one or more optical fiber cores is opposed to a light emitter that emits visible light. It is a method of passing visible light through the entire line and visually checking the cross section of the other end to check for the presence or absence of an optical fiber core wire that does not emit light.By allowing visible light to pass through the optical fiber cable, visual inspection by humans is possible, The troublesome work such as peeling work and connector attaching work is omitted, and quick inspection is possible. In addition, the bundle fiber is an optical fiber
Since it is directly focused without coating, it does not couple with the light source.
Easy to handle because of high efficiency and flexibility
It This inspection method is suitable for a relatively short distance optical fiber cable whose construction history is clear.

[0024] Then, <br/> in the light guide inspection apparatus therefor, and an optical fiber cable having a bundle fiber and one or more optical fibers, one end of the bundle fiber
Diameter of a connector with a conical hole diverging from the start
Optically coupled by simply inserting an optical fiber cable on the side
Therefore, it is applicable even if the optical fiber cable diameter is slightly different.
Come, the efficiency of optical coupling is improved, the structure is simple, and easy to handle.

[Brief description of drawings]

FIG. 1 is a schematic view showing the method of the present invention and the apparatus of the present invention.

FIG. 2 is a sectional view of a bundle fiber.

FIG. 3 is a cross-sectional view of an optical fiber cable.

FIG. 4 is a cross-sectional view of an optical fiber core wire.

FIG. 5 is a schematic view showing another device of the present invention.

FIG. 6 is a device block diagram showing a conventional light guide inspection device.

[Explanation of symbols]

 1,50 Light emitter 3,51 Connector

Claims (2)

(57) [Claims] 1. An optical fiber cable having one or more optical fiber core wires, of which cross-sections at both ends are opposed to light emitters that emit visible light, and visible light is passed through the entire optical fiber core wire. Guide the optical fiber cable by checking the cross section of the other end and checking for the presence of optical fiber cores that do not emit light.
In the inspection method, the light emitter comprises a light source and a bundle filter.
Fix the end faces of the fiber and bundle fiber by facing the light source
It is formed with a box that
Install a connector with a conical hole that expands from this point.
The vertical cross section of one end of the optical fiber cable
By inserting it into the large diameter side of the connector,
The visible light from the light source in front of the end face of the rib.
The optical fiber via the bundle fiber and the connector.
A method for inspecting a light guide of an optical fiber cable, which is characterized in that the light is collectively incident on the core wire . 2. The optical fiber cable having one or more optical fiber core wires is provided with an optical fiber cable having a cross section at one end facing a light emitter for emitting visible light through a connector.
Pass visible light through the entire core wire and visually check the cross section at the other end.
Optical fiber that checks for the presence of optical fiber
In a light guide inspection device for a cable, the light emitter is
Bundled fiber and light provided at the other end of the bundle fiber
Source and the other end of the fiber bundle facing the light source.
And a box for fixing the connector.
A divergent conical hole starting from one end of the dollar fiber
The vertical cross section of the optical fiber cable on the large diameter side.
A light guide inspection device for an optical fiber cable, which is formed so as to be insertable therein .