JP2009014681A - Optical fiber hot-line detector and optical termination box - Google Patents

Abstract

A hot-wire detection device and an optical termination box capable of easily and safely detecting a hot-wire state of an optical fiber are provided.
A clad portion is formed such that a surface opposite to a silicon substrate is relatively thin. As a result, a thickness (minimum thickness) d0 of a portion between a core portion and a silicon substrate is reduced. In contrast, the thickness (minimum thickness) d1 of the portion of the core portion 20 opposite to the silicon substrate 22 is relatively small. The light detecting element 3 is bonded and fixed to a portion where the thickness of the clad portion 21 is the minimum thickness d1. Therefore, the optical signal leaking from the thin portion provided in the clad portion 21 of the optical waveguide 2 is detected by the light detecting element 3, so that the optical fiber is detected by bending the optical fiber one by one. The live line state can be detected easily and safely.
[Selection] Figure 1

Description

  The present invention relates to a live line detection device that detects whether or not an optical fiber is in a live line state, and an optical termination box equipped with the live line detection device.

  In recent years, optical fibers have been rapidly spreading as communication lines, and optical fiber cables drawn into optical communication stations of optical communication companies and general office buildings can be used for many optical fiber cords for optical wiring in a station or building. An optical termination box (also referred to as an optical termination tray) is used to connect to the cable. In addition, this type of optical termination box is equipped with a hot-wire detection device that detects whether or not each core wire (optical fiber core wire) of the optical fiber cord is in a live state (a state in which an optical signal is transmitted). (See, for example, Patent Document 1).

A conventional hot-wire detection device described in Patent Document 1 includes a convex portion having a curved surface that bends an optical fiber core, a concave portion that can be fitted to the convex portion with a space therebetween, and an optical fiber. Detected by a light leaking portion having an elastic body inserted into the space together with the core wire, a light detection portion for detecting light leaking from a bent portion of the optical fiber core wire through an opening provided in the concave portion, and a light detection portion It is comprised with the photon detection terminal which has a display part which displays detection information (information of whether it is a live line state). Then, the tip of the detection part of the light detection terminal is inserted into the opening of the light leaking part and fitted, and the recessed part is formed by applying pressure vertically downward to the optical fiber core wire in the fitted state. If the optical fiber core wire is moved to the convex side and bent between the convex portion and the concave portion, and an optical signal is transmitted to the optical fiber core wire, the optical signal is transmitted from the bent portion of the optical fiber core wire. Therefore, it is possible to detect whether or not it is a live line state by detecting the leaked optical signal with the light detection unit.
JP 2007-85934 A

  However, in the above-described conventional example described in Patent Document 1, it is necessary to detect the live state of the optical fiber core one by one using a photodetection terminal, and a great amount of time and labor are required for the detection work. There is a problem that the optical fiber core wire may be damaged or broken by mechanical bending.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a hot-wire detection device and an optical termination box capable of easily and safely detecting a hot-wire state of an optical fiber. .

  In order to achieve the above object, the invention of claim 1 is a hot-wire detection device that detects whether or not an optical fiber is in a hot-wire state, and is provided between an incident-side optical fiber and an outgoing-side optical fiber. An optical waveguide having a core part inserted into the optical fiber core and connected to the core of each optical fiber, a clad part including the core part, wherein a part of the clad part is relatively thin relative to other parts, And a photodetecting element that detects an optical signal leaking from the portion of the clad portion of the optical signal transmitted to the waveguide.

  According to the first aspect of the present invention, since the optical signal leaking from the thin portion provided in the cladding portion of the optical waveguide is detected by the photodetecting element, the optical signal is bent one by one and detected in comparison with the conventional example. Thus, the live state of the optical fiber can be detected easily and safely.

  According to a second aspect of the present invention, in the first aspect of the present invention, the core portion of the optical waveguide is formed such that the shape of the portion facing the photodetecting element across the portion is different from the other portions. And

  According to the invention of claim 2, the detection sensitivity is improved by increasing the amount of the optical signal leaking from the core part to the clad part.

  According to a third aspect of the present invention, in the invention of the second aspect, the core portion of the optical waveguide is formed such that a portion facing the photodetecting element across the portion is formed wider than the other portions. .

  According to a fourth aspect of the present invention, in the invention of the second aspect, the core portion of the optical waveguide is formed such that a portion facing the photodetecting element across the portion is formed narrower than the other portions. To do.

  According to a fifth aspect of the present invention, in the second aspect of the present invention, the core portion of the optical waveguide is formed in a shape in which a portion of the portion facing the photodetecting element across the portion is cut out. And

  The invention of claim 6 is characterized in that, in the invention of claim 1, the core portion of the optical waveguide is divided at a portion facing the photodetecting element across the portion.

  According to the third to sixth aspects of the invention, the detection sensitivity is further improved by increasing the amount of the optical signal leaking from the core part to the clad part.

  In order to achieve the above object, the invention of claim 7 is a hot-wire detection device for detecting whether or not the optical fiber is in a hot-wire state, and is provided with one or more V-grooves for holding the optical fiber. The optical fiber clad of the optical fiber held in the V-groove of the substrate is provided in a portion that is relatively thinner than the other portions, and the thin wall in the clad among the optical signals transmitted to the optical fiber is provided. And a light detection element for detecting an optical signal leaking from the portion.

  According to the seventh aspect of the present invention, since the optical signal leaking from the thin portion provided in the clad of the optical fiber is detected by the light detecting element, compared with the conventional example in which the optical fiber is bent and detected one by one. The live line state of the optical fiber can be easily detected.

  In order to achieve the above object, the invention according to claim 8 includes the hot-wire detection device according to any one of claims 1 to 7 and the hot-wire detection device inside, and an optical fiber on the incident side is introduced. And a box body from which the optical fiber on the emission side is led out, and a notification means that is exposed on the box body and notifies the detection result of the hot-wire detection device.

  According to the invention of claim 8, it is possible to easily detect the hot-wire state of the optical fiber as compared with the conventional example in which the optical fiber is bent and detected one by one, and the detection result by the hot-wire detection device It is possible to constantly monitor whether or not the optical fiber is in a live line state by informing the information by the informing means.

  According to the present invention, there is provided an optical fiber hot-line detecting device and a termination box that can easily detect a hot-wire state of an optical fiber as compared with a conventional example in which optical fibers are bent and detected one by one. it can.

  Embodiments of an optical fiber hot-wire detection device and an optical termination box according to the present invention will be described below in detail with reference to the drawings.

(Embodiment 1)
As shown in FIG. 1, the hot-wire detection device 1 according to the present embodiment includes an optical waveguide 2 inserted between an optical fiber cord 100 on the incident side and an optical fiber cord 101 on the outgoing side, and an optical signal leaking from the optical waveguide 2. And a plurality of light detecting elements 3 (only one is shown in FIG. 1).

  Each of the optical fiber cords 100 and 101 on the incident side and the output side is formed by covering four optical fiber core wires 110 with a sheath, and optical fiber arrays FA1 and FA2 for connecting to the optical waveguide 2 are arranged at the tip thereof. Has been. The optical fiber arrays FA1 and FA2 are arranged between a V-groove substrate having a plurality of (four in this embodiment) V-grooves (not shown) for holding the optical fiber core wire 110 formed on the surface, and the V-groove substrate. It is comprised with the cover which pinches | interposes the optical fiber core wire 110 hold | maintained at the V groove. However, since this type of optical fiber array FA1, FA2 is well known in the art, illustration and description of the detailed structure are omitted. Further, instead of the optical fiber arrays FA1 and FA2, a multi-fiber ferrule having a holding hole for inserting and holding a plurality of optical fiber core wires 110 may be used.

  The optical waveguide 2 includes four core parts 20 (only one is shown in FIG. 1A) connected to the cores of the optical fiber cores 110 as shown in FIG. The clad part 21 to be included is formed on the silicon substrate 22. However, a glass substrate may be used instead of the silicon substrate 22. The core part 20 and the clad part 21 are formed so that the refractive index is set to have the same or similar optical confinement effect as that of the core and clad of the optical fiber core wire 110, respectively. Further, the clad portion 21 is formed so that the surface opposite to the silicon substrate 22 is relatively thin, and as a result, the core is smaller than the thickness (minimum thickness) d0 of the portion between the core portion 20 and the silicon substrate 22. The thickness (minimum thickness) d1 of the portion 20 on the side opposite to the silicon substrate 22 (the upper side in FIG. 1B) is relatively small. Then, an adhesive 6 made of a material having a higher refractive index than that of the cladding part 21 is applied to a part facing the core part 20 on the upper surface of the cladding part 21, that is, a part where the thickness of the cladding part 21 is the minimum thickness d1. The light detection element 3 is bonded and fixed. The light detection element 3 is formed of a photodiode, and is fixed to the optical waveguide 2 with an adhesive 6 in a direction in which the light receiving surface faces the clad portion 21.

  Here, as an example, the thickness d0 = 20 [μm] of the clad part 21 and the thickness (minimum thickness) d1 [μm] of the clad part 21 when the thickness (minimum thickness) of the adhesive 6 is 10 [μm], FIG. 2 shows a result obtained by simulation of the relationship between the loss [dB] of the optical signal due to the light leaking from the core part 20 through the clad part 21 to the outside. However, the thickness of the core part 20 is 6 [μm], the refractive index of the core part 20 is 1.525, the refractive index of the cladding part 21 is 1.52, the refractive index of the adhesive 6 is 1.55, and the light detecting element 3 Was assumed to have a refractive index of 3. As is apparent from FIG. 2, the loss can be regarded as almost zero if the thickness d1 of the cladding portion 21 is 8 [μm] or more, and the loss increases exponentially when the thickness d1 is less than about 8 [μm]. . Accordingly, if the minimum thickness d1 above the core portion 20 (opposite side of the silicon substrate 22) in the cladding portion 21 is set to 3 [μm], for example, light (optical signal) leaking through the cladding portion 21 is about 1 dB. It can be generated and can be detected by the light detecting element 3.

  Of course, the amount of light that leaks is added to the overall loss, so it is desirable that it be as small as possible. Accordingly, the amount of light leaking by adjusting the refractive index of the core / cladding, the thickness and refractive index of the adhesive 6, and the thickness d1 of the cladding part 21 above the core part 20 in accordance with the sensitivity of the light detecting element 3. By increasing / decreasing, the light detection element 3 can detect light leaking in a state where the overall loss is suppressed. As an extreme example, even if the refractive index of the adhesive 6 is the same as or lower than the refractive index of the cladding part 21, leakage light is generated by reducing the thickness of the adhesive 6 and the thickness d1 of the cladding part 21. Can be made.

  FIG. 3A shows a plan view of the optical termination box 7 of the present embodiment. The optical termination box 7 includes a live line detection device 1, a box body 70 in which the live line detection device 1 is housed, and an optical fiber cord 100 on the incident side is introduced. Informing means for informing the detection result by the line detection device 1 is provided.

  The box body 70 is formed in a flat rectangular box shape whose upper cover can be freely opened and closed, and is provided with an introduction port 70a for introducing the optical fiber cord 100 on the incident side on one end face facing in the longitudinal direction. A plurality (four in the illustrated example) of optical connectors 71 are attached to the other end face facing each other. The incident-side optical fiber cord 100 introduced from the introduction port 70a is accommodated in the box 70 with the extra length curved in an arc shape, and is relayed by the multi-fiber optical connector 102 attached to the tip thereof. The optical fiber cord 103 is connected. The other end of the relay optical fiber cord 103 is connected to the optical waveguide 2 via the incident-side optical fiber array FA1. Further, an optical fiber cord (so-called fan-out cord) 104 for multi-core single core conversion is connected to the output side of the optical waveguide 2 via an optical fiber array FA2, and a plurality of optical fiber core wires 104a of the optical fiber cord 104 are connected. Are respectively connected to the optical connector 71.

  The notification means includes a converter 4 that converts a current signal output from each of the light detection elements 3 of the hot-wire detection device 1 into a voltage signal, and the optical fiber cord 100 on the incident side using the voltage signal converted by the converter 4. It comprises a display unit 5 for notifying (displaying) a live line state. The converter 4 and the display unit 5 operate by receiving power supply from a power supply device 300 described later. The display unit 5 displays a plurality of display elements 50 such as light emitting diodes (four in the illustrated example) and a plurality of display elements 50 according to a voltage signal (detection signal of the live line detection device 1) received from the converter 4. A drive circuit (not shown) that is driven individually, and a housing 51 that houses the drive circuit and has four display elements 50 exposed on the side surfaces, are provided along the longitudinal direction of the box 70. A housing 51 is fixed to the side surface of the housing. However, the converter 4 may be housed in the housing 51 of the display unit 5. In the display unit 5, when the detection signal of the live line detection device 1 exceeds a predetermined threshold value or when it is determined that the detection signal is in the live line state from the voltage distribution state of the detection signal, the drive circuit detects the detection signal. Since the display element 50 corresponding to is driven, the display element 50 driven by the drive circuit emits light, thereby displaying that each optical fiber core of the optical fiber cord 100 on the incident side is in a live state. it can.

  The optical termination box 7 of this embodiment is stored in a rack 200 as shown in FIG. The rack 200 has a vertically long rectangular parallelepiped shape, and a bottom plate portion is fixed to the floor by a plurality of anchors 201. In the rack 200, the plurality of optical termination boxes 7 are supported by the support portion 202 so as to overlap in the thickness direction. The optical fiber cable FC is drawn into the rack 200 through the top plate, and a plurality of optical fiber cords 100 accommodated in the optical fiber cable FC are respectively introduced into the box body 70 of the optical termination box 7 from the introduction port 70a. ing. The optical fiber core wire 210 connected to the optical connector 71 of each optical termination box 7 is drawn from the rack 200 through the top plate. Furthermore, a power supply device 300 that is connected to an external commercial power source via a power cable 301 and creates a DC power source from the commercial AC power source is fixed to the bottom plate of the rack 200. Note that power is supplied from the power supply device 300 to the hot-wire detection device 1 accommodated in the optical termination box 7 via a power supply cable 302 connected to the power supply device 300. However, the optical termination box 7 may be stored in a box attached to the wall, or the power supply device 300 may be installed outside the rack 200 or the box.

  Thus, in this embodiment, an optical signal transmitted through the optical fiber core 110 on the incident side is detected by the live line detection device 1, and the detection signal is converted by the converter 4 and displayed on the display unit 5. Therefore, it is possible to always monitor whether or not the optical fiber core wire 110 is in the live state by displaying on the display unit 5. In addition, according to the present embodiment, the optical signal leaking from the thin portion (the portion having the minimum thickness d1) provided in the clad portion 21 of the optical waveguide 2 is detected by the light detecting element 3, so that the optical fiber 1 There is an advantage that the live state of the optical fiber can be detected easily and safely (without bending the optical fiber) as compared with the conventional example in which the detection is performed by bending one by one. Instead of arranging the display elements 50 on the side surfaces of the box body 70, for example, as shown in FIG. 3C, the corresponding display elements 50 are arranged in the vicinity of the optical connector 71 on the upper surface of the optical termination box 7. This makes it easy to determine the correspondence between the optical connector 71 and the display of the live line state by the display element 50.

  By the way, in order to improve the detection sensitivity of the hot-wire detection device 1, in the core portion 20 of the optical waveguide 2, a portion (hereinafter referred to as “opposing”) that opposes the light detection element 3 across a portion that becomes the minimum thickness d1 of the cladding portion 21. Called “parts.”) The shape of X may be different from other parts. Specifically, as shown in FIG. 4 (a), the facing portion X is tapered with respect to the other portions, or the facing portion X is changed to other portions as shown in FIG. 4 (b). On the other hand, it may be formed in a shape that is tapered and narrowed, that is, a shape in which a part of the facing portion X is cut out as shown in FIG. If the facing portion X is formed in such a shape, the reflection angle at the interface between the core portion 20 and the cladding portion 21 changes at the facing portion X, and light is not totally reflected at the interface, but is incident on the cladding portion 21. As a result, the amount of light detected by the light detection element 3 increases and the detection sensitivity can be improved. Note that arrows in FIGS. 4A and 4B indicate optical paths of optical signals transmitted (propagated) through the core unit 20. However, when the opposing portion X has a wide or narrow shape, it is not always necessary to have a target shape as shown in FIGS. 4A and 4B. As shown, the shape may be asymmetric. Alternatively, even when the core portion 20 is divided at the facing portion X as shown in FIG.

(Embodiment 2)
As shown in FIG. 5, the hot-wire detection device 10 of the present embodiment connects the optical fiber core wire 100a of the optical fiber cord 100 on the incident side and the optical fiber core wire 101a of the optical fiber cord 101 on the output side. Optical fiber arrays 11 and 11 and a light detection element 12 are provided.

  The optical fiber array 11 includes a V-groove substrate 11a having a plurality of V-grooves 11c provided on the upper surface, and a cover 11b placed on the upper surface of the V-groove substrate 11a so as to partially cover the V-groove 11c. The The depth of the V groove 11c is set to be smaller than the diameter (cladding diameter) of the optical fiber core wire 100a and larger than the radius thereof. Then, the clad 100c of the optical fiber core wire 100a held in the V groove 11c is shaved until it is substantially flush with the upper surface of the V groove substrate 11a as shown in FIG. A part is thin. The light detection element 12 is formed of a photodiode, and is bonded and fixed to the thin portion of the optical fiber core wire 100a by the adhesive 13 with the light receiving surface facing the core 100b. The output of the light detection element 12 is converted from a current signal to a voltage signal by the converter 4 in the same manner as in the first embodiment, and the display unit 5 displays the live line state of the optical fiber core wire 100a according to the voltage signal. It is supposed to be.

  Thus, in the live line detection device 10 of the present embodiment, the cladding 100c of the optical fiber core wire 100a connected to the optical fiber arrays 11 and 11 is partially thinned, and the light detection element 12 is provided in the thinned portion. Since the optical signal leaking to the outside is detected through the thin-walled portion, it is not necessary to provide the optical waveguide 2 unlike the hot-wire detection device 1 of the first embodiment, so that the size and cost can be reduced by reducing the number of components. There is an advantage that down can be achieved. As in the first embodiment, the optical termination box 7 can be configured by housing the hot-wire detection device 10 of the present embodiment in the box 70.

1 shows Embodiment 1 of the present invention, in which (a) is a schematic configuration diagram of a hot-wire detection device, and (b) is a partial cross-sectional view. It is explanatory drawing same as the above. (A) is a top view of the optical termination box same as the above, (b) is a sectional view of a rack in which the optical termination box is housed, and (c) is a perspective view in which a part of the optical termination box is omitted. (A)-(f) is sectional drawing which shows the core part of the optical waveguide in the same as the above. Embodiment 2 of this invention is shown, (a) is a schematic block diagram of a hot-wire detection apparatus, (b) is a fragmentary sectional view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hot-line detection apparatus 2 Optical waveguide 3 Photodetection element 20 Core part 21 Clad part

Claims (8)

A hot-wire detection device that detects whether an optical fiber is in a hot-wire state,
A core part inserted between the optical fiber on the incident side and the optical fiber on the output side and connected to the core of each optical fiber, and a clad part containing the core part, and a part of the clad part with respect to the other part An optical fiber comprising: an optical waveguide that is relatively thin; and a light detection element that detects an optical signal leaking from the portion of the cladding portion of the optical signal transmitted to the optical waveguide. Live line detector.   2. The optical fiber hot-wire detection device according to claim 1, wherein the core portion of the optical waveguide is formed such that the shape of the portion facing the light detection element across the portion is different from that of the other portion. .   3. The optical fiber hot-wire detection device according to claim 2, wherein the core portion of the optical waveguide is formed such that a portion facing the light detection element across the portion is wider than other portions.   3. The optical fiber hot-wire detection device according to claim 2, wherein the core portion of the optical waveguide is formed such that a portion facing the light detection element across the portion is narrower than other portions.   3. The optical fiber hot-wire detection device according to claim 2, wherein the core portion of the optical waveguide is formed in a shape in which a portion of the portion facing the photodetecting element is cut out with the portion interposed therebetween. .   2. The optical fiber hot-wire detection device according to claim 1, wherein the core portion of the optical waveguide is divided at a portion facing the light detection element with the portion interposed therebetween. A hot-wire detection device that detects whether an optical fiber is in a hot-wire state,
A substrate provided with one or a plurality of V-grooves for holding an optical fiber, and a portion of the optical fiber clad held in the V-groove of the substrate that is relatively thinner than other portions, An optical fiber hot-line detecting device comprising: a light detecting element for detecting an optical signal leaking from the thin portion of the clad among the optical signals transmitted to the optical fiber.   A live line detection device according to any one of claims 1 to 7, a box body in which the live line detection device is housed and an optical fiber on the incident side is introduced and an optical fiber on the output side is led out, An optical termination box comprising an informing unit that is exposed in the box and notifies a detection result of the hot-wire detection device.

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