JP6200800B2 - Optical fiber side input / output device and jig structure - Google Patents

Description

  The present invention relates to a technique for bending out an optical fiber and extracting light to the outside.

  In order to identify one optical fiber from a plurality of optical fibers in a non-destructive manner, optical fiber core contrast is performed. The optical fiber core wire comparison is completed by receiving the reference light incident on the optical fiber with a light receiving device. For example, in the outside line, the operation of receiving the reference light incident on the optical fiber from the optical line housing building (switching office) at the connection point of the outside line is performed. In order to simplify the work, a light receiving device using an optical fiber side input / output technology is provided.

  FIG. 10 is a diagram for explaining an optical fiber side input / output technique. As shown in FIG. 10A, when the optical fiber is bent, leakage light is emitted from the bent portion (bent portion). As shown in FIG. 10B, the optical system of the light receiving device is formed by pressing the optical fiber against a cylinder or the like to form a bent portion and abutting the probe fiber on the position where leaked light is received.

  A light receiving device using this type of technique physically bends an optical fiber with a jig or the like, and detects leaked light with a photodiode or the like through a probe fiber. According to this technology, work such as cutting an existing optical fiber or fusing another optical fiber becomes unnecessary, so that the communication network can be efficiently maintained and operated.

  By the way, an optical fiber ribbon (or a single filament) is often covered with a tube for protection or the like. The ease of detection of leaked light varies greatly depending on the presence or absence of a tube. It is relatively easy to detect leakage light from an optical fiber from which a tube has been removed, such as a connection point of an external line.

  On the other hand, it is not easy to detect light leaked from an optical fiber covered with a tube (hereinafter referred to as a tubed optical fiber). This is because leakage light is weakened by passing through the gap between the tube and the optical fiber core wire. For example, such a case occurs in a section downstream of an optical splitter (star coupler) having a PDS (Passive Double Star) type optical line configuration.

Nado, "Optical fiber side-in / out method", Optical fiber application technology technical report, IEICE technical report, vol. 111, no. 69, OFT2011-3, pp. 11-14

As described above, there is a situation in which leakage light from an optical fiber covered with a tube must be detected. This will be described below with reference to the drawings.
FIG. 11 is a diagram illustrating an example of a relationship between an optical line terminal (OLT) and an optical network unit (ONU). The OLT 101 installed in the switching center 100 is connected to a closure 400 near the subscriber's home 300 via an IDM (optical switch) 102 and an optical cable 200. The closure 400 includes an eight-branch type optical splitter 401, for example. The ONU 301 in the subscriber house 300 is connected to one of the downstream terminals of the optical splitter 401 via an optical fiber.

  As shown in FIG. 12, a section between the optical splitter 401 and the switching center 100 is referred to as an upstream side, and a section between the optical splitter 401 and the subscriber's home 300 is referred to as an upstream side. The optical fiber on the downstream side of the optical splitter 401 is an optical fiber with a tube and is covered with a tube for protecting the fiber glass.

  FIG. 13 is a diagram for explaining the work of confirming the communication status between the ONU and the OLT. For example, in access line construction, it is necessary to confirm the communication status between the OLT and the ONU prior to the start of construction. Therefore, if the optical fiber core wire on the downstream side of the optical splitter 401 inside the closure 400 is bent to leak uplink communication light (wavelength 1.31 μm), and if this leaked light can be received, communication between the ONU 301 and the OLT is possible. You can check the situation.

  However, in the wiring point closure (400) of the PDS type optical line configuration as shown in FIG. 13, the extra length section on the downstream side of the optical splitter 401 until it is connected to the optical drop cable is a protective tube. It has a covered structure. In many optical fibers with a tube, since the inner diameter of the tube is larger than the outer diameter of the core wire, there is a gap (air layer) between the core wire and the tube.

  As shown in FIG. 14, when the optical cable 200 covered with the tube 201 is bent, the rigidity of the tube 201 and the fiber core wire 202 is different, so that the tube 201 and the fiber core 202 are not bent uniformly. It may occur or the originally existing void may become large. Since the leaked light from the bent portion enters the probe fiber 203 through the gap, the intensity of the leaked light reaching the outside of the tube is significantly reduced for optical reasons. Therefore, even if the tube 201 is formed of a material having a good translucency (transparent member), there is a possibility that the amount of light reaching the probe fiber 203 is drastically reduced due to the gap and it is impossible to confirm the presence or absence of communication light.

  The present invention has been made in view of the above circumstances. An object of the present invention is to provide an optical fiber side input / output device and its jig structure that can reliably receive leaked light from a bent portion of an optical fiber covered with a tube. It is to provide.

An embodiment of the present invention for achieving the above object will be described below.
(1) An optical fiber side input / output device according to the present invention is an optical fiber side input / output device applicable to an optical fiber with a tube including a core wire and a tube covering the core wire with a gap interposed therebetween. A first jig having a curved concave portion and a convex portion having a shape corresponding to the concave portion, and bending the optical fiber with a tube between the concave portion and the convex portion to bend into the core wire. A second jig that forms a portion, a pressure contact portion that presses the tube against the core wire on a path of leakage light that deforms the tube and leaks from the bent portion together with the formation of the bent portion, and the bent portion A probe fiber that is abutted from the outside of the tube and into which the leakage light is incident.

  That is, according to the aspect of (1), by inserting the optical fiber with a tube between the concave portion of the first jig and the convex portion of the second jig, a bent portion is formed in the core wire and the tube is deformed. The tube is pressed against the core wire along the path of the leaked light leaking from the bent portion. As a result, there is no gap, and the intensity of leaked light incident on the probe fiber can be increased.

  (2) In the optical fiber side input / output device according to the present invention, in (1), the pressure contact portion is formed in the first jig and has a guide groove that guides the optical fiber with a tube along the concave portion. And D ≦ d + t × 2, where D is the depth of the guide groove, d is the outer diameter of the core wire, and t is the thickness of the tube.

  That is, according to the aspect of (2), the tube is pressed against the core wire on the path of the leaked light leaking from the bent portion while being pressed against the guide groove. As a result, there is no gap, and the intensity of leaked light incident on the probe fiber can be increased.

  (3) The optical fiber side input / output device according to the present invention is the optical fiber side input / output device according to (1), wherein the pressure contact portion is a guide groove formed in the first jig and guiding the tube-equipped optical fiber along the recess. The guide groove includes a first groove that overlaps the path of the leaked light, and a second groove that is formed continuously with the first groove and is deeper and narrower than the first groove. Where D is the outer diameter of the core wire, d is the thickness of the tube, t is the thickness of the second groove, and B ≦ d + t × 2. It is.

  That is, according to the aspect (3), the tube is pressed against the core wire on the path of the leaked light leaking from the bending portion while being pressed against the guide groove, and the alignment accuracy of the core wire to the probe fiber is improved. Can be made.

  That is, according to the present invention, it is possible to provide an optical fiber side input / output device and its jig structure that can reliably receive leaked light from a bent portion of an optical fiber covered with a tube.

FIG. 1 is a diagram illustrating an optical fiber side input / output device according to a first embodiment. FIG. 2 is a cross-sectional view of the fiber core wire 202 with a tube. FIG. 3 is a cross-sectional view taken along the line AA ′ of the structure shown in FIG. FIG. 4 is a diagram showing a fiber core wire 202 with a tube deformed by pressing the convex jig 20 against the concave jig 10. FIG. 5 is a schematic diagram showing that light propagating through the core 21 leaks in the state shown in FIG. FIG. 6 is a diagram illustrating an optical fiber side input / output device according to the second embodiment. 7 is a cross-sectional view taken along the line BB ′ of the structure shown in FIG. FIG. 8 is a schematic diagram showing that light propagating through the core 21 leaks in the state shown in FIG. 7B. 9 is a cross-sectional view taken along the line CC ′ of the structure shown in FIG. FIG. 10 is a diagram for explaining an optical fiber side input / output technique. FIG. 11 is a diagram illustrating an example of the relationship between the OLT and the ONU. FIG. 12 is a diagram illustrating the upstream side and the downstream side with respect to the optical splitter 401. FIG. 13 is a diagram for explaining the work of confirming the communication status between the ONU and the OLT. FIG. 14 is a diagram for explaining that a void is generated by bending.

  Embodiments of the present invention will be described with reference to the drawings. Embodiment described below is an example and this invention is not limited to these forms.

[First Embodiment]
FIG. 1 is a diagram illustrating an optical fiber side input / output device according to a first embodiment. This optical fiber side input / output device can be suitably applied to form a bent portion in a fiber cored wire 202 with a tube as an optical fiber with a tube. Hereinafter, the fiber core wire 202 with the tube is referred to as a fiber core wire 202 for simplicity.

  The optical fiber side input / output device shown in FIG. 1 includes a concave jig 10 and a convex jig 20. The concave jig 10 includes a curved concave portion. The convex jig 20 includes a convex portion having a shape corresponding to the concave portion of the concave jig 10. The concave portion and the convex portion are formed of metal, resin, or the like according to the shape of the bent portion 204 to be formed in the fiber core wire 202.

  The convex jig 20 is pressed so as to approach the convex jig 20 in a state where the fiber core wire 202 is sandwiched between the convex jig 20. As a result, the structure including the fiber core wire and the tube is bent as a whole, and a bent portion 204 that emits leaked light is formed in the fiber core wire 202.

  The probe fiber 203 is abutted against the bent portion 204 via the matching agent 30 that is a transparent gel-like member, for example. As a result, leaked light emitted from the bent portion 204 is incident on the photodiode 205 via the probe fiber 203.

  FIG. 2 is a cross-sectional view of the fiber core wire 202. FIG. 2A is a cross-sectional view obtained by cutting the fiber core wire 202 along a plane perpendicular to the longitudinal direction thereof. FIG. 2B is a cross-sectional view obtained by cutting the fiber core wire 202 along a plane parallel to the longitudinal direction thereof.

  The fiber core wire includes a fiber glass composed of a core 21 and a clad 22 of an outer layer thereof, and a fiber coating 23 covering the fiber glass. Further, the fiber core wire is covered with the tube 25 through the gap 24. In the embodiment, the outer diameter of the tube 25 is 0.9 mm, the inner diameter is 0.5 mm, and the thickness (thickness: t) is 0.2 mm.

  The outer diameter (d) of the fiber core wire is smaller than the inner diameter of the tube 25, for example, 0.25 mm. This creates a gap between the inner wall of the tube 25 and the fiber core. Under the above sizes, the distance between the inner wall of the tube 25 and the fiber core wire, that is, the size of the air gap is 0.125 mm.

FIG. 3 is a cross-sectional view taken along the line AA ′ of the structure shown in FIG. As can be seen from the dotted line in FIG. 1, FIG. 3 shows a cross section at the apex of the bent portion 204. As illustrated, the concave jig 10 includes a guide groove 40 dug into a substantially U shape along the concave portion of the concave jig 10. The guide groove 40 is provided to guide the fiber core wire 202 along the concave portion of the concave jig 10. That is, the bending portion 204 can be easily formed by placing the fiber core wire 202 along the guide groove 40 and pressing the convex jig 20 in this state.
The size of the guide groove 40 is characterized by the groove width W and the depth D. The groove width W is the distance between two vertices in the opening of the guide groove 40. The depth D is the distance between the line connecting the two vertices and the bottom side of the guide groove 40. The bottom side corresponds to the emission position of the leaked light in FIG.

  In the embodiment, by setting the guide groove 40 to an appropriate size according to the size of the fiber core wire 202 to be used, at least a gap on a path where leakage light leaking from the bent portion 204 reaches the probe fiber is eliminated. Like that. That is, the guide groove 40 is formed with such a width and depth that the tube 25 is pressed against (contacted with) the fiber core wire at that portion, and the gap is crushed in a state where the convex jig 20 is pressed until it stays in the concave jig 10. To.

  Specifically, first, the groove width W of the guide groove 40 is made smaller than the outer diameter of the tube 25. Accordingly, when the fiber core wire 202 is pushed into the concave jig 10 by the convex jig 20, the tube 25 is fitted into the guide groove 40 while being deformed, and the gap is crushed and disappears in the process. In the embodiment, the groove width W is set to W = 0.65 mm. When the fiber core wire 202 is pushed into the groove of this size, a tube having a thickness of 0.2 mm is closely attached to the optical fiber having an outer diameter of 0.25 mm from both the left and right sides (0.25 + 0.2 × 2 = 0.65).

Further, the depth D of the guide groove 40 is D = 0.45 mm. Generally, the guide groove 40 is formed so that a relationship of D ≦ d + t × 2 is established among the depth D of the guide groove 40, the outer diameter d of the fiber core wire, and the thickness t of the tube 25. . As described above, since t = 0.2 mm and d = 0.25 mm, D = d + t × 2.
The guide groove 40 thus formed with an appropriate size deforms the tube 25 together with the formation of the bent portion 204, and press-contacts the tube 25 with the fiber core wire on the path of leakage light leaking from the bent portion 204. Acts as

  FIG. 4 is a diagram showing a fiber core wire 202 that is deformed by pressing the convex jig 20 against the concave jig 10. When the tube 25 having a thickness t = 0.2 mm and an outer diameter = 0.9 mm is pushed into the guide groove 40 having a depth D = 0.45 mm and a groove width W = 0.65 mm, the tube 25 is formed along the shape of the guide groove 40. Deforms and adheres closely to a fiber core having an outer diameter d = 0.25 mm. That is, there is no air gap around 360 degrees surrounding the fiber coating 23.

  FIG. 5 is a schematic diagram showing that light propagating through the core 21 leaks in the state shown in FIG. The leaked light reaches the probe fiber 203 without passing through the gap and is guided to the photodiode 205. Since the inner wall of the tube 25 and the fiber core wire (fiber coating 23) are in contact with each other without a gap, the intensity of the leaked light from the bent portion 204 hardly decreases until it enters the probe fiber 203. Therefore, a sufficient signal intensity can be obtained in the photodiode 205, and the presence or absence of an optical signal flowing through the optical fiber covered with the tube can be reliably determined.

  As described above, in the first embodiment, the size and shape of the guide groove 40 for mounting the fiber core wire with tube 202 on the concave jig 10 are devised, and the tube 25 is deformed together with the formation of the bent portion 204. The fiber coating 23 was brought into close contact. That is, the cross-sectional depth D of the guide groove 40 at the emission point of the leaked light is set to D ≦ the outer diameter d of the optical fiber core wire + the thickness t × 2 of the tube 25.

With such a configuration, when the convex jig 20 is pushed into the concave jig 10, the geometric requirement for eliminating the air layer in the path until the leaked light reaches the probe fiber 203 is satisfied. Therefore, it becomes possible to receive leaked light without loss. As a result, the communication state of the upstream signal (wavelength: 1.31 μm) from the ONU 301 can be easily confirmed in the core line control test in the situation as shown in FIG. 13, and the construction can be carried out smoothly.
Accordingly, it is possible to provide an optical fiber side input / output device and its jig structure that can reliably receive the leaked light from the bent portion of the optical fiber covered with the tube.

[Second Embodiment]
In the first embodiment, as shown in FIG. 4, the air gap is eliminated so as to surround the fiber coating 23. Instead, in the second embodiment, the air gap is eliminated at least in the path of the leaked light.

  FIG. 6 is a diagram illustrating an optical fiber side input / output device according to the second embodiment. 6, parts common to FIG. 1 are denoted by the same reference numerals, and only different parts will be described here. 6 shows substantially the same state as FIG. 1, but the shape of the guide groove 40 is different from FIG. In the second embodiment, the size of the guide groove 40 will be described with reference to the BB ′ cross section.

  7 is a cross-sectional view taken along the line BB ′ of the structure shown in FIG. In the second embodiment, as shown in FIG. 7A, the width W of the guide groove (shown with reference numeral 41 for distinction) is W = 1.15 mm, and the depth D is D = 0. .65 mm. Since the width W (1.15 mm) of the guide groove 41 is wider than the outer diameter (0.9 mm) of the tube 25, it is shown in FIG. 7A in a state where no pressing force is applied to the convex jig 20. As a result, a gap is generated. This gap is for escaping the lateral expansion of the tube 25 and is referred to as a relief portion 50.

  When a pressing force is applied and the convex jig 20 and the concave jig 10 are brought into close contact with each other, the tube 25 is crushed in the vertical direction, that is, in the direction in which the pressing force is applied, as shown in FIG. As a result, the tube 25 spreads in the horizontal direction and comes into close contact with the fiber coating 23 from the vertical direction, eliminating the gap on the path of leaked light. The spread of the tube 25 in the lateral direction is absorbed by the escape portion 50.

  In the second embodiment, the width W of the guide groove 41 is W = 1.15 mm. This is a value (0.9 + 0.125 + 0.125) obtained by adding a gap of 0.25 mm on the left and right to the tube outer diameter of 0.9 mm. Moreover, the depth D of the external groove 41 was D = 0.65 mm. This is a value obtained by subtracting 0.25 mm from 0.9 mm (0.9-0.125-0.125), assuming that a tube having an outer diameter of 0.9 mm is crushed by a gap of 0.25 mm above and below. is there.

  Supplementary explanation will be made with reference to FIG. That is, when the fiber core wire 202 is inserted into a groove shallower than the tube outer diameter of 0.9 mm, a step as shown in FIG. By making this level difference the same as the width of the upper and lower gaps, the state of FIG. 7B is realized. When light propagates to the core 21 in the state of FIG. 7B, the light leaks from the bent portion as shown in FIG. 8B. This leaked light reaches the probe fiber 203 without passing through the gap and is guided to the photodiode 205. Since the inner wall of the tube 25 and the fiber core wire (fiber coating 23) are in contact with each other with no gap, the intensity of the leaked light from the bent portion hardly decreases until it enters the probe fiber 203. Therefore, a sufficient signal intensity can be obtained in the photodiode 205, and the presence or absence of an optical signal flowing through the optical fiber covered with the tube can be reliably determined.

  In the second embodiment, a fiber core wire 202 with a tube having the size shown in FIG. 2A is guided to a guide groove 41 having a width W = 1.15 mm and a depth D = 0.65 mm, and a convex mold is cured. The tool 20 and the concave jig 10 are pressed. Thus, the fiber coating 23 is brought into close contact with the tube 25 from the direction in which the pressing force is applied. Therefore, in the second embodiment, the same effect as that of the first embodiment can be obtained, and the optical fiber side-in can be received reliably from the leaked light from the bent portion of the optical fiber covered with the tube. It becomes possible to provide an output device and its jig structure.

[Third Embodiment]
9 is a cross-sectional view taken along the line CC ′ of the structure shown in FIG. In the third embodiment, the size of the guide groove formed in the concave jig 10 is made different between the portion overlapping the leakage light path and the other portion. That is, when the groove formed in the vicinity of the section BB 'in FIG. 6 is the guide groove 41, for example, the width of the section (referred to as guide groove 42) corresponding to the section CC' in FIG. The depth was made narrower and deeper than the guide groove 41. The guide groove 42 is formed continuously with the guide groove 41.

  As shown in FIG. 9A, the width of the guide groove 42 is narrower than that of the tube 25. When the convex jig 20 is pressed from this state, the fiber core wire 202 is pushed into the groove as shown in FIG. 9B, and pressure is generated from the inner wall of the guide groove 42 toward the fiber core 21. By such an action, the center line of the guide groove 42 and the fiber core 21 are naturally positioned on a straight line.

  As described above, in the third embodiment, in the vicinity of the bent portion 204, D ≦ d + t between the depth D of the guide groove 41, the outer diameter d of the fiber core wire (fiber coating 23), and the thickness t of the tube 25. X2 is satisfied. In a portion other than the vicinity of the bent portion 204, the width B of the guide groove 42 is set to B ≦ d + t × 2.

  In the shape shown in FIG. 7 (second embodiment), the fiber coating 23 and the inner wall of the tube 25 are easily brought into contact with each other, but there is a possibility that the optical fiber moves laterally because no lateral force acts. . That is, there is a possibility that the fiber core 21 may be detached from the position of the probe fiber 203.

  Therefore, in the third embodiment, the width of the guide groove 42 is narrowed at a portion other than the vicinity of the bent portion 204 to improve the alignment accuracy. Further, since the guide groove is left in the shape shown in FIG. 7 (second embodiment) in the portion overlapping the leakage light path, the effect of maintaining the leakage light intensity remains the same. By doing in this way, it becomes possible to aim at coexistence with the ease of aligning the fiber core 21 and obtaining the leakage light of strong light intensity.

The present invention is not limited to the above embodiment. For example, in the third embodiment, the guide groove where the leaked light is emitted is wide and shallow, and the other part is narrow and deep. Instead, almost all of the guide groove may have a wide and shallow shape (the shape of the guide groove 41), and only a part of the guide groove may be narrow and a deep groove (the shape of the guide groove 42) may be formed. In this way, the purpose of improving the alignment accuracy can be easily achieved.
In addition, the shape and material of the concave block and the convex block, the type of the cured resin, and the like can be variously modified without departing from the gist of the present invention.

  In short, the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in each embodiment. Furthermore, you may combine suitably the component covering different embodiment.

  DESCRIPTION OF SYMBOLS 10 ... Concave jig | tool, 20 ... Convex jig | tool, 21 ... Core, 22 ... Cladding, 23 ... Fiber coating, 24 ... Air gap, 25 ... Tube, 30 ... Matching agent, 40, 41, 42 ... Guide groove, 50 ... Relief part, 100 ... exchange, 200 ... optical cable, 201 ... tube, 202 ... fiber core with tube, 203 ... probe fiber, 204 ... bent part, 205 ... photodiode, 300 ... subscriber's house, 400 ... closure, 401 ... optical splitter, 101 ... OLT, 301 ... ONU

Claims (4)

An optical fiber side input / output device applicable to an optical fiber with a tube comprising a core wire and a tube covering the core wire with a gap interposed therebetween,
A first jig having a concave recess;
A second jig that has a convex portion having a shape corresponding to the concave portion, and forms a bent portion in the core wire by sandwiching the optical fiber with a tube between the concave portion and the convex portion;
A pressure contact part that presses the tube against the core wire on a path of leakage light that deforms the tube and leaks from the bending part together with the formation of the bending part;
A probe fiber that is abutted on the bent part from the outside of the tube and enters the leaked light ;
The pressure contact portion includes a guide groove that is formed in the first jig and guides the optical fiber with a tube along the recess.
The guide groove includes a first groove that overlaps the leakage light path, and a second groove that is formed continuously with the first groove and is deeper and narrower than the first groove. Fiber side input / output device. When the depth of the first groove is D, the outer diameter of the core wire is d, the thickness of the tube is t, and the width of the second groove is B, D ≦ d + t × 2, and The optical fiber side input / output device according to claim 1, wherein B ≦ d + t × 2 . A jig structure for bending an optical fiber with a tube comprising a core wire and a tube covering the core wire with a gap interposed therebetween,
A first jig having a concave recess;
A second jig that has a convex portion having a shape corresponding to the concave portion, and forms a bent portion in the core wire by sandwiching the optical fiber with a tube between the concave portion and the convex portion;
A pressure-contact portion that deforms the tube together with the formation of the bent portion and presses the tube against the core wire on a path of leakage light leaking from the bent portion;
The pressure contact portion includes a guide groove that is formed in the first jig and guides the optical fiber with a tube along the recess.
The guide groove includes a first groove that overlaps the leakage light path, and a second groove that is formed continuously with the first groove and is deeper and narrower than the first groove. Ingredient structure. When the depth of the first groove is D, the outer diameter of the core wire is d, the thickness of the tube is t, and the width of the second groove is B, D ≦ d + t × 2, and The jig structure according to claim 3, wherein B ≦ d + t × 2.

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