JP4728132B2 - Optical cord - Google Patents

Description

  The present invention relates to an optical cord that enables a core wire contrast in a communication system using an optical fiber.

  When constructing and maintaining an optical fiber communication network, it is necessary to identify the optical fibers of the manhole closures and the premises cabinets at the work site. That is, when constructing and maintaining an optical fiber communication network, it is necessary to select and specify one optical fiber to be operated from a plurality of optical fibers. This operation is called core control.

  FIG. 12 is a schematic diagram illustrating an example of the work of core wire contrast. An example in which an OLT (Optical Line Terminal) 211 and an ONU (Optical Network Unit) 216 installed in a subscriber's house 222 are connected by an optical fiber 214 and the optical fiber 214 is specified at an intermediate point 221 will be described. . On the lower side of the optical fiber 214, while bending the optical fiber 214 using the bending portion 215, the reference light is radiated from the side surface of the optical fiber 214, and this is detected by the light receiver 223. The bent portion 215 includes a convex member 215a and concave portions 215b and 215c. The control light is light that is incident on the optical fiber 214 via the optical coupler 213 from the light source 212 disposed in the base station 220.

  When this method is applied to a service core, the communication quality must be compared without degrading the communication quality. Therefore, using the feature that light on the longer wavelength side is more likely to leak, a communication wavelength of 1.31 μm / 1 is currently available. For 1.6 .mu.m, a 1.6 .mu.m band on the longer wavelength side is used as control light (for example, see Patent Document 1).

The intermediate point 221 is, for example, a closure in a manhole or a cabinet on the premises. The optical fiber 214 is usually covered with a resin layer, and this resin layer deteriorates when irradiated with ultraviolet rays. For this reason, the optical fiber 214 from the base station 220 to the intermediate point 221 and the optical fiber 214 from the intermediate point 221 to the ONU 216 installed in the subscriber's house 222 are made of resin with a skin that can prevent ultraviolet rays. The perimeter of the layer is covered. That is, except for the optical fiber 214 disposed in the bent portion 215, an outer skin containing a substance capable of preventing ultraviolet rays such as carbon covers the periphery of the resin layer (see, for example, Patent Document 2). However, since the optical fiber 214 installed in the closure or cabinet is used as the bent portion 215, it has not been covered with a light-shielding outer sheath.
JP-A-6-221958 Japanese Patent Laid-Open No. 11-60286

  Optical cords housed in closures and cabinets are not covered with a light-shielding outer cover, but conventionally there were few opportunities to open the closures or cabinets. Deterioration could be prevented.

  However, with the diversification of services of communication systems using optical fibers, opportunities for opening closures and cabinets are increasing. Open the closures and cabinets while working on the core. For this reason, since almost all of the optical cords accommodated in the closure or cabinet are irradiated with ultraviolet rays, the speed at which the optical cord is deteriorated is increased.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical cord that can control a core wire and can prevent deterioration of a resin layer due to ultraviolet irradiation from the outside.

  The optical cord according to the present invention is characterized in that a leakage window for leaking the reference light is provided in at least a part of the ultraviolet prevention layer covering the periphery of the resin layer, and the reference light is received therefrom.

  Here, the optical cord includes an optical fiber core wire in which the periphery of the clad is covered with resin. Further, an optical fiber cord in which the periphery of the clad is covered with a resin and a sheath is included. Further, an optical fiber tape core wire having a plurality of clads covered with resin is included. Further, an optical fiber tape cord having a plurality of optical fiber cords in which the periphery of the clad is covered with a resin and a sheath is included.

Light code according to the present invention covers an optical fiber for propagating light, covers the side surface of the optical fiber, and a resin layer that transmits light of a specific wavelength propagating through the optical fiber, the outer periphery of the resin layer, Leakage that leaks light of the specific wavelength to the outside of the UV prevention layer by removing a part of the UV prevention layer and the UV prevention layer that prevents the resin layer from being irradiated with UV rays from the outside. A window and a light-shielding cover that covers the leakage window, prevents external ultraviolet irradiation to the leakage window, and can expose the leakage window by moving . By providing the light shielding cover, it is possible to prevent the resin layer from being irradiated with ultraviolet rays from the leakage window when the core wire comparison is not performed.

  In the optical cord according to the present invention, the light shielding cover is a cylindrical body that surrounds the outer periphery of the ultraviolet ray preventing layer, and the leakage window is exposed by the cylindrical body moving in the longitudinal direction of the optical fiber. It is preferable. Since the light shielding cover can be displaced from the portion where the leakage window is disposed, the leakage window can be easily bent. Further, since the light shielding cover is a cylindrical body, the light shielding cover is not dropped from the optical cord, and the light shielding cover can be prevented from being lost.

  In the optical cord according to the present invention, the light shielding cover is a semi-cylindrical body that covers a part of the outer circumferential direction of the ultraviolet ray preventing layer, and the semi-cylindrical body moves in the longitudinal direction of the optical fiber. Thus, it is preferable that the leakage window is exposed. When the leakage window covers a part of the outer periphery of the resin layer in the circumferential direction, the leakage window can be covered with a semi-cylindrical light shielding cover. Since the light shielding cover is a semi-cylindrical body, it is easy to attach the ultraviolet protection layer to the outer periphery. In addition, since the light shielding cover is a semi-cylindrical body, even when a plurality of optical fibers are arranged inside one ultraviolet ray prevention layer, the leakage window can be exposed for each optical fiber.

  In the optical cord according to the present invention, the light-shielding cover is a semi-cylindrical body that covers a part of a circumferential direction of the outer periphery of the ultraviolet ray prevention layer, and the semi-cylindrical body has the longitudinal direction of the optical fiber as a central axis. It is preferable that the leakage window is exposed by rotating. When the leakage window covers a part of the outer periphery of the resin layer in the circumferential direction, the leakage window can be covered with a semi-cylindrical light shielding cover. Since it is not necessary to move the light shielding cover in the longitudinal direction of the optical fiber, the leakage window and the light shielding cover can be integrated. Therefore, it is easy to produce an optical cord. Further, since the outer diameter of the optical cord can be made uniform, handling such as accommodation of the optical cord becomes easy.

  The optical cord according to the present invention further includes a connection portion that connects one end of the light shielding cover to the ultraviolet ray prevention layer, and the other end of the light shielding cover rotates around the connection portion as a fulcrum so that the leakage window It is preferable to expose. Since the connection portion is integrated with the ultraviolet ray prevention layer, it is easy to attach or replace the light shielding cover. Further, since one end of the light shielding cover is connected to the ultraviolet ray preventing layer, the light shielding cover does not fall off from the optical cord, and the loss of the light shielding cover can be prevented.

  Since the optical cord according to the present invention is covered with the ultraviolet ray prevention layer except for the leakage window, it is possible to prevent the resin layer covering the optical fiber accommodated in the closure or cabinet from being irradiated with ultraviolet rays. Since the leakage window leaks light of a specific wavelength, core line contrast can be performed. Here, by providing the leakage window, the area of the resin layer irradiated with ultraviolet rays from the outside can be reduced. Further, it is possible to easily prevent the resin layer from being irradiated with ultraviolet rays from the leakage window using a tool for preventing ultraviolet rays.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiment described below is an example of the configuration of the present invention, and the present invention is not limited to the following embodiment.

(Embodiment 1)
FIG. 1 is a schematic diagram showing a first form of the optical cord according to the present embodiment. An optical cord 91 shown in FIG. 1 shows a side surface in the longitudinal direction of the optical cord 91 and a longitudinal section of a part thereof. The optical cord 91 covers the optical fiber 11 that propagates light, the side surface of the optical fiber 11, the resin layer 12 that transmits light of a specific wavelength that propagates through the optical fiber 11, and the outer periphery of the resin layer 12. An ultraviolet ray prevention layer 13 for preventing the ultraviolet ray from being irradiated from the outside, and a leakage window 14 provided at least in part of the ultraviolet ray prevention layer 13 for leaking light of the specific wavelength to the outside of the ultraviolet ray prevention layer 13; Is provided.

  2A and 2B are cross-sectional views of the optical cord, where FIG. 2A shows an A-A ′ cross section and FIG. 2B shows a B-B ′ cross section. The resin layer 12 covers the outer periphery of the side surface in the longitudinal direction of the optical fiber 11, and the ultraviolet protection layer 13 covers the outer periphery of the resin layer 12. The ultraviolet prevention layer 13 is disposed on the outer peripheral surface of the optical cord 91. As shown in FIG. 2 (b), the leakage window 14 is arranged in place of the ultraviolet ray prevention layer 13. No layer is provided between the leakage window 14 and the resin layer 12, and light leaking from the optical fiber 11 is directly transmitted to the leakage window 14 through the resin layer 12. In addition, when providing the layer different from the resin layer 12 between the leak window 14 and the resin layer 12, it is preferable that the layer permeate | transmits the light of a specific wavelength. In this embodiment, the term “transmission” means that the transmittance is not 0%, for example, preferably 10% or more and 100% or less. The same applies to the following.

  FIG. 3 is a cross-sectional view showing a specific example of the optical cord. In the optical cord 200 shown in FIG. 3, the outer periphery of the core 51 is covered with a clad 52, a buffer layer 53, a coating 54, a reinforcing material 55, and a sheath 56 in this order. The core 51 and the clad 52 are, for example, glass, and light is propagated in the core 51. The optical fiber (reference numeral 11 in FIG. 1) is, for example, a core 51 through which light is propagated, and may include a clad 52 that propagates light in the core 51. The buffer layer 53 is, for example, an ultraviolet curable resin, and the resin layer (reference numeral 12 in FIG. 1) corresponds to this.

  The coating 54 is, for example, a resin having flexibility. Examples of the resin having flexibility include nylon resin, polyester non-halogen resin, and polyamide resin. The reinforcing material 55 has a predetermined tensile elastic modulus and bending rigidity. For example, glass fiber such as alkali glass roping or glass roping, carbon fiber such as carbon fiber, and aramid fiber such as Kevlar (registered trademark). Or there is a complex of these. The sheath 56 is, for example, a thermoplastic resin such as polyvinyl chloride, polyester elastomer, or polyaramid.

  The coating 54, the reinforcing material 55, the sheath 56, or two or more layers thereof serve as an ultraviolet ray prevention layer (reference numeral 13 in FIG. 1). For example, if the sheath 56 contains a component that prevents ultraviolet rays, the sheath 56 becomes the ultraviolet ray preventing layer (reference numeral 13 in FIG. 1). Further, when the reinforcing material 55 contains carbon fiber and thereby prevents ultraviolet rays, the reinforcing material 55 becomes an ultraviolet ray preventing layer (reference numeral 13 in FIG. 1). In addition, when the buffer layer 53 is covered as an outer skin in which two or more of the coating 54, the reinforcing material 55, and the sheath 56 are integrally formed, and the outer skin includes a function that prevents ultraviolet rays, the outer skin is included. Becomes an ultraviolet ray preventing layer (reference numeral 13 in FIG. 1).

  The optical cord according to the present embodiment includes an optical fiber core wire in which the periphery of the clad 52 is covered with a buffer layer 53. The optical cord according to the present embodiment includes an optical fiber cord in which the periphery of the clad 52 is covered with a buffer layer 53 and a sheath 56. Further, the optical cord according to the present embodiment includes an optical fiber tape core wire having a plurality of clad 52 covered with a buffer layer 53. The optical cord according to the present embodiment includes an optical fiber tape cord having a plurality of optical fiber cords in which the periphery of the clad 52 is covered with the buffer layer 53 and the sheath 56.

  The optical fiber 11 shown in FIG. 1 propagates light. For example, it is transparent to propagating light, and is, for example, oxide glass such as quartz glass, resin, or ceramics. Examples of the resin include a fluorine resin and an acrylic resin. The optical fiber 11 further propagates control light. The reference light is light having a longer wavelength than the communication wavelength band, and is, for example, the 1.6 μm band when the communication wavelength band is 1.55 μm.

  A resin layer 12 shown in FIG. 1 is a layer formed of a resin that transmits light of a specific wavelength propagating through the optical fiber 11. Light of a specific wavelength is control light. The resin is, for example, an ultraviolet curable resin. Examples of the ultraviolet curable resin include a silicon resin and an epoxy resin. Moreover, resin which has a photocationic polymerization initiator or an inorganic fine particle size filler as a main component may be used.

  The ultraviolet ray prevention layer 13 shown in FIG. 1 prevents the resin layer 12 from being irradiated with ultraviolet rays from the outside. For example, by containing a component that absorbs or reflects ultraviolet rays, the transmission of ultraviolet rays can be prevented. The component that absorbs ultraviolet rays includes, for example, a black substance, and examples thereof include black organic compounds such as carbon black, synthetic rubber, and Teflon (registered trademark). The component that reflects ultraviolet rays is, for example, a white substance such as titanium oxide or zinc oxide. The ultraviolet ray preventing layer 13 is preferably a layer on the outer peripheral surface of the optical cord 91, whereby deterioration of the layers other than the resin layer 12 due to ultraviolet rays can be prevented.

The leakage window 14 shown in FIG. 1 leaks the light having the specific wavelength to the outside of the ultraviolet prevention layer 13. The leakage window 14 is, for example, an exposed portion of the resin layer 12 that is not covered with the ultraviolet prevention layer 13. The leakage window 14 may be an outer skin that does not contain a component that prevents ultraviolet rays and can transmit light of a specific wavelength. The leakage window 14 may be provided with an optical member that transmits light of a specific wavelength. The optical member is, for example, a member that transmits infrared rays. Examples of such an optical member include Si, quartz glass, Ge, ZnSe, ZnS, MgF _2, and a resin that transmits infrared rays. Examples of the resin that transmits infrared rays include methacrylic resin. The leakage window 14 is preferably not transparent with respect to wavelengths other than the specific wavelength, and for example, a wavelength filter is preferably provided. It is preferable that the leak window 14 is not easily damaged, and it is preferable that hard carbon (DLC: Diamond Like Carbon) is included on the surface. Moreover, it is preferable that the core wire is as flexible as possible.

  The leakage window 14 shown in FIG. 1 is provided in at least a part of the ultraviolet ray prevention layer 13. For example, it may be provided at one place in the longitudinal direction of the optical cord 91 or may be provided at a plurality of places. The leakage windows 14 may be provided at regular intervals in the longitudinal direction of the optical cord 91. The area of the leakage window 14 is preferably small.

  An example of an optical cord manufacturing method in the present embodiment will be described. First, the optical fiber 11 is produced by drawing from the optical fiber preform. Next, the optical fiber 11 is passed through a die filled with a liquid ultraviolet curable resin, and the resin layer 12 is formed by curing the ultraviolet curable resin. Next, the one formed with the resin layer 12 is passed through a die filled with a liquid resin as a raw material for the ultraviolet prevention layer 13, and the one after passing through the die is heated to cure the ultraviolet prevention layer 13. Next, the resin layer 12 is passed through a die filled with the raw material for the liquid ultraviolet ray prevention layer 13, and the ultraviolet ray prevention layer 13 is formed around the resin layer 12. The portion of the ultraviolet protection layer 13 where the leakage window 14 is provided is peeled off to expose the resin layer 12, thereby forming the leakage window 14.

  An example of use of the optical cord in the present embodiment will be described with reference to FIG. FIG. 4 is a schematic diagram illustrating an example of a core wire contrast. The optical cord 91 is bent at the portion where the leakage window 14 is provided, and the reference light 101 leaked from the leakage window 14 is received by the light receiving element 102. At this time, by setting the core wire contrast device so that the transparent portion provided with the leakage window 14 is positioned at the light receiving element 102, the light receiving element 102 can receive the leaked light leaked from the reference light 101. it can.

  Since the optical cord 91 shown in FIG. 1 is covered with the ultraviolet ray preventing layer 13 except for the leakage window 14, the resin layer 12 can be protected from ultraviolet rays except for the leakage window 14. Thereby, even if it is the optical code 91 in which a core wire contrast is possible, degradation by irradiation of the ultraviolet rays of the resin layer 12 can be prevented. Further, by providing the leakage window 14, the area of the resin layer 12 irradiated with external ultraviolet rays can be reduced. Since the portion deteriorated by the ultraviolet rays can be reduced, it can be easily accommodated in a light-shielding tray, and the transparent portion with the leakage window 14 is accommodated in the tray except when performing core wire contrast, so that the resin layer of the optical cord 91 12 can be prevented from being irradiated with ultraviolet rays. Further, since the area of the leakage window 14 is small, it is possible to easily prevent the resin layer 12 from being irradiated with ultraviolet rays, for example, by blocking the leakage window 14 using a light shielding tape.

  5A and 5B show a second form of the optical cord, where FIG. 5A is a schematic diagram, and FIG. 5B is a C-C ′ sectional view. In the optical cord 92 shown in FIG. 5A, the leakage window 14 is provided in a part of the outer periphery of the ultraviolet ray preventing layer 13 in the circumferential direction. The leakage window 14 is provided not to cover all directions around the resin layer 12 but to cover a part of the outer periphery of the resin layer 12 in the circumferential direction. As shown in FIG. 5B, the leakage window 14 is formed by surrounding the resin layer 12 with a layer formed by the ultraviolet prevention layer 13 and the leakage window 14. As shown in FIG. 5B, the leakage window 14 is preferably provided so as to cover half or less of the outer periphery of the resin layer 12. The leakage window 14 may be provided with optical components such as a lens and a light guide for guiding the leaked reference light. By providing the optical component, the reference light can be guided to the outside of the optical cord 92 even when the area of the leakage window 14 is small.

  By setting the core wire contrast device so that the transparent portion where the leakage window 14 is provided is positioned at the light receiving element (reference numeral 102 in FIG. 4), the leakage light that the reference light leaks to the outside of the optical cord 92 is reduced. Light can be received by a light receiving element (reference numeral 102 in FIG. 4). When the core wire comparison is not performed, the resin layer 12 of the optical cord 92 can be protected from ultraviolet rays by accommodating the leakage window 14 in a light-shielding tray provided in a closure or cabinet.

  Since the area of the leakage window 14 is smaller than that of the first embodiment of the optical cord, the area of the resin layer 12 exposed to ultraviolet rays irradiated from the outside can be reduced. In addition, the portion to be protected from ultraviolet rays can be easily accommodated in the tray. In addition, it is preferable that the thickness of the ultraviolet-ray prevention layer 13 and the leakage window 14 is uniform, and thereby, the surface of the optical cord can be smoothed, and handling when performing the core wire comparison can be facilitated.

(Embodiment 2)
In the optical cord 91 shown in FIG. 1 and the optical cord 92 shown in FIG. 5A, the leakage window 14 is covered, the ultraviolet irradiation from the outside to the leakage window 14 is prevented, and the leakage window 14 is moved by moving. It is preferable to further include a light-shielding cover (not shown) that can be exposed. The light shielding cover prevents or transmits ultraviolet light by absorbing or reflecting ultraviolet light. Those which absorb or reflect ultraviolet rays are those described in the ultraviolet ray preventing layer 13. The light shielding cover covers the leakage window 14 and is preferably arranged in a wider range than the leakage window 14. That is, it is preferable to cover the leakage window 14 and the ultraviolet ray prevention layer 13 around the leakage window 14. For this reason, the light shielding cover is preferably formed of a flexible member in order to ensure the flexibility of the optical cord. As the flexible member, for example, a member similar to the member used for covering the optical cord (reference numeral 54 in FIG. 3) or the sheath (reference numeral 56 in FIG. 3) can be used. By providing the light shielding cover, it is possible to prevent the resin layer 12 from being irradiated with ultraviolet rays from the leakage window 14. The light shielding cover is preferably openable and closable. The light shielding cover is opened to expose the leakage window 14, and the light shielding cover is closed to protect the leakage window 14 from ultraviolet rays. Here, the exposure means a state in which light having a specific wavelength propagating through the optical fiber can be leaked to the outside of the ultraviolet ray prevention layer 13. A specific example of the light shielding cover will be described below.

  FIG. 6 is a schematic diagram showing a third form of the optical cord. The optical cord 93 shown in FIG. 6 further includes the light shielding cover 15 that is the first form of the light shielding cover in addition to the optical cord 91 shown in FIG. The light shielding cover 15 is a cylindrical body that surrounds the entire circumferential direction of a part of the outer circumference of the ultraviolet ray preventing layer 13 in the longitudinal direction. When the light shielding cover 15 moves in the direction H, the light shielding cover 15 is disposed at the position of the light shielding cover 15 ′ and covers the leakage window 14. The direction H is the longitudinal direction of the optical cord 93, that is, the longitudinal direction of the optical fiber. Then, the light shielding cover 15 is moved in the longitudinal direction H of the optical fiber so that the light shielding cover 15 is disposed at the position of the light shielding cover 15 to expose the leakage window 14. Since the light shielding cover 15 can be shifted from the portion where the leakage window 14 is disposed, the leakage window 14 can be easily bent. Moreover, since the light shielding cover 15 is a cylindrical body, the light shielding cover 15 is not dropped from the optical cord 93, and the light shielding cover can be prevented from being lost.

  When performing the core line contrast, the light shielding cover 15 having light shielding properties is slid and opened in the direction H, and the core line contrast is set so that the transparent leakage window 14 is located at the position of the light receiving element. Leaked light leaking outside the cord can be received by the light receiving element. When the core line contrast is not performed, the light shielding cover 15 having a light shielding property is slid in the direction H to the position of the light shielding cover 15 ′, and the light shielding cover 15 is closed to shield the ultraviolet rays, and the resin layer ( The reference numeral 12) in FIG. 1 can be protected from ultraviolet rays.

  The inner diameter of the light shielding cover 15 is preferably larger than the outer diameter of the ultraviolet protection layer 13 so that the light shielding cover 15 can be easily moved in the direction H. Further, it is preferable that the light shielding cover 15 is an elastic body in which a returning force acts in a direction in which the inner diameter decreases so that the light shielding cover 15 can be fixed to the ultraviolet ray prevention layer 13. For example, the cylindrical body is preferably a curved plate that forms a cylinder. By forming the cylindrical body with a curved plate, the light shielding cover 15 can be easily attached to and detached from the ultraviolet ray prevention layer 13. Further, it is preferable to provide a fixing means with the ultraviolet ray preventing layer 13 that prevents the movement of the light shielding cover 15 in the direction H.

  7A and 7B show a fourth form of the optical cord, where FIG. 7A is a schematic diagram, and FIG. 7B is a cross-sectional view along D-D ′. The optical code 94 shown in FIG. 7A further includes a light shielding cover 15 in which the optical code 92 shown in FIG. 5A is the first form of the light shielding cover. In this case, the light shielding cover 15 is preferably a semi-cylindrical body that covers a part of the outer periphery of the ultraviolet protection layer 13 in the circumferential direction, like a light shielding cover 15 ′ shown in FIG. For example, like the light shielding cover 15 ′ shown in FIG. 7B, a slit 32 along the direction H is provided, and becomes a part of a cylindrical body surrounding a part of the periphery of the ultraviolet ray prevention layer 13. Preferably it is. Here, the direction H is the longitudinal direction of the optical cord 94. Further, the semi-cylindrical body is, for example, half of the circumferential direction of the cylindrical body. As shown in FIG. 7B, the semi-cylindrical body is preferably half or more in the circumferential direction of the cylindrical body, and can be fixed to the optical cord by the shape of the light shielding cover 15, for example. The semi-cylindrical body is preferably half or more in the circumferential direction of the cylindrical body, and thereby, a plurality of the semi-cylindrical bodies are disposed inside one ultraviolet ray prevention layer 13 such as an optical fiber tape core wire or an optical fiber tape cord. Even when an optical fiber (reference numeral 11 in FIG. 1) is disposed, the leakage window 14 can be exposed for each optical fiber.

  The light shielding cover 15 is formed of an elastic body, and the shape of the cross section in the direction H is preferably C-shaped. Since the light shielding cover 15 is provided with the slit 32, the light cord 92 shown in FIG. 5A is inserted into the light shielding cover 15 from the slit 32 so as to cover the outer periphery of the ultraviolet protection layer 13. 15 can be attached, so that the optical cord 94 can be easily manufactured.

  FIG. 8 shows a fifth form of the optical cord, where (a) is a schematic view and (b) is an E-E ′ cross-sectional view. The optical code 95 shown in FIG. 8A further includes a light shielding cover 16 in which the optical code 92 shown in FIG. 5A is the second form of the light shielding cover. The light shielding cover 16 is a semi-cylindrical body that covers a part of the outer circumference of the ultraviolet ray preventing layer 13 in the circumferential direction. The optical cord 95 includes a transmission window 31 that transmits a specific wavelength in a part of the cylindrical body 21 in the circumferential direction, and the light shielding cover 16 and the transmission window 31 constitute the cylindrical body 21. The transmission window 31 is formed of a member that is transparent to light having a specific wavelength, for example. The same optical member as the leakage window 14 can be used for the transmission window 31. The transmissive window 31 may be a space where nothing is arranged.

  In the optical cord 95, it is preferable that the leakage window 14 is exposed when the cylindrical body 21 rotates in the direction I. The direction I is a rotation direction with the longitudinal direction of the optical cord 95, that is, the longitudinal direction of the optical fiber (not shown) as the central axis. Since the light shielding cover 16 is opened and closed by the rotational movement of the cylindrical body 21, it is not necessary to move the cylindrical body 21 in the direction H. Here, the direction H is the longitudinal direction of the optical cord 95, that is, the longitudinal direction of the optical fiber. For this reason, it is easy to integrate and attach the leakage window 14 and the light shielding cover 16, so that the optical cord 95 can be easily manufactured. Further, since the outer diameter of the optical cord 95 can be made uniform, handling such as accommodation of the optical cord becomes easy.

  In the optical cord 95, it is preferable that the leaking window 14 is exposed by moving the cylindrical body 21 in the direction H. The direction H is the longitudinal direction of the optical cord 95, that is, the longitudinal direction of the optical fiber. The operation of the optical cord 95 is the same as the operation of the optical cord 93 shown in FIG.

  The cylindrical body 21 preferably has an inner diameter larger than the outer diameter of the ultraviolet protection layer 13 so that the surface friction with the ultraviolet protection layer 13 is small. Moreover, it is preferable that the cylindrical body 21 is an elastic body in which a returning force works in a direction in which the inner diameter decreases so that the cylindrical body 21 can be fixed to the ultraviolet ray prevention layer 13. For example, the cylindrical body is preferably a curved plate that forms a cylindrical shape. By forming the cylindrical body 21 with a curved plate, the cylindrical body 21 can be easily attached to and detached from the ultraviolet protection layer 13. Moreover, it is preferable to provide a fixing means for the ultraviolet prevention layer 13 on the cylindrical body 21.

  FIG. 9 is a schematic diagram showing a sixth form of the optical cord. The optical code 96 shown in FIG. 9 further includes the light shielding cover 17a and the light shielding cover 17b, which are the third form of the light shielding cover, in the optical code 91 shown in FIG. The optical cord 96 further includes a connection portion 22 that connects one end of the light shielding cover 17 a and the light shielding cover 17 b to the ultraviolet ray prevention layer 13. One end of the light shielding cover 17a and the light shielding cover 17b is, for example, one end in the longitudinal direction of the optical cord 96 shown in FIG. When the light shielding cover 17 a and the light shielding cover 17 b are disposed at the positions of the light shielding cover 17 a ′ and the light shielding cover 17 b ′, the light shielding cover 17 a and the light shielding cover 17 b cover the leakage window 14. Then, each of the other ends of the light shielding cover 17a and the light shielding cover 17b not connected to the connection portion 22 rotates in the direction J with the connection portion 22 as a fulcrum, so that the leakage window 14 is Exposed. In the direction J, the other end of each of the light shielding cover 17a and the light shielding cover 17b with the connection portion 22 as the rotation center is a surface perpendicular to the longitudinal direction of the optical cord 96 passing through the connection portion 22 from the surface of the ultraviolet protection layer 13. It is the direction toward. In the third embodiment of the light shielding cover, the number of light shielding covers may be one or more, and the leakage window 14 may be covered with one light shielding cover. Further, the leakage window 14 may be covered with three or more light shielding covers.

  The connection part 22 is a part where the light shielding cover 17 a and the light shielding cover 17 b are connected to the ultraviolet ray prevention layer 13. The connection is, for example, by welding or adhesion. There is also a fixing tool. Examples of the fixing tool include mechanical fixing such as a screw, fixing by a spring in which a return force acts in a direction in which the inner diameter decreases, and fixing by an adhesive tape.

  When the light shielding cover 17a and the light shielding cover 17b cover the leakage window 14, the leakage window 14 is preferably difficult to be exposed. For example, the light shielding cover 17a and the light shielding cover 17b are preferably formed of a flexible member, and the light shielding cover 17a and the light shielding cover 17b are preferably attached to the ultraviolet ray prevention layer 13. Moreover, it is preferable that at least a part of the light shielding cover 17a and the light shielding cover 17b overlap each other. Further, it is preferable that the light shielding cover 17a and the light shielding cover 17b can be fixed to each other. Further, it is preferable that the light shielding cover 17 a and the light shielding cover 17 b form a cylindrical shape and cover the outer periphery of the ultraviolet protection layer 13.

  When the core line contrast is not performed, the light shielding cover 17a and the light shielding cover 17b are disposed at the positions of the light shielding cover 17a 'and the light shielding cover 17b'. When performing the core line contrast, the light shielding cover 17a and the light shielding cover 17b having light shielding properties are opened by tearing, and the transparent portion where the leakage window 14 is provided is the position of the light receiving element (reference numeral 102 in FIG. 4). By setting the core wire contrast device in this way, the leaked light in which the control light leaks to the outside of the optical cord can be received by the light receiving element. When the core line contrast is not performed, the light shielding cover 17a and the light shielding cover 17b are rotated and moved in the direction J to the positions of the light shielding cover 17a ′ and the light shielding cover 17b ′, and the light shielding cover 17a and the light shielding cover 17b are closed to thereby prevent ultraviolet rays. The resin layer (reference numeral 12 in FIG. 1) in the optical cord 96 can be protected from ultraviolet rays by shielding light.

  FIG. 10 is a schematic diagram showing a seventh form of the optical cord. The optical code 97 shown in FIG. 10 further includes a light shielding cover 17a and a light shielding cover 17b, which are the third form of the light shielding cover, in which the optical code 92 shown in FIG. The optical cord 97 is the same as the optical cord 96 shown in FIG. 9 except for the leakage window 14.

  FIG. 11 shows an eighth form of the optical cord, where (a) is a schematic view and (b) is an F-F ′ sectional view. In the optical cord 98 shown in FIG. 11A, the light shielding cover 17 a shown in FIG. 10 covers the leakage window 14. The leakage window 14 is provided so as to cover a part of the circumferential direction rather than the entire circumferential direction around the resin layer 12. For this reason, the light shielding cover 17a can cover the leakage window 14 without surrounding the entire circumferential direction of the portion where the leakage window 14 is disposed. The light shielding cover 17a is easy to manufacture because it is not necessary to circulate the outer periphery of the ultraviolet ray prevention layer 13 as in the sixth embodiment of the optical cord. Further, since the portion where the light shielding cover 17a is provided is a part of the outer periphery of the portion where the leakage window 14 is arranged, one sheath (symbol 56 in FIG. 3) like a tape cord. When a plurality of optical fibers (reference numeral 11 in FIG. 1) are arranged in the optical fiber, a leakage window 14 can be provided for each optical fiber. Thereby, even if it is a case where multiple optical fibers are arrange | positioned inside the ultraviolet-ray prevention layer 13, irradiation of the ultraviolet-ray to the resin layer of the outer periphery of optical fibers other than the optical fiber which performs a core line contrast can be prevented.

  In the first form of the optical code to the eighth form of the optical code, the optical code is a plurality of optical fibers (reference numeral 11 in FIG. 1) in one sheath (reference numeral 56 in FIG. 3) like a tape cord. May be arranged. In this case, it is preferable to provide the leakage window 14 for each optical fiber arranged in one sheath (reference numeral 56 in FIG. 3). A common light shielding cover may be used for the plurality of leakage windows 14, or a light shielding cover may be provided for each leakage window 14. If a light-shielding cover is provided for each leakage window 14, even when a plurality of optical fibers are arranged inside the ultraviolet ray prevention layer 13, the resin layer on the outer periphery of the optical fiber other than the optical fiber that performs the core wire comparison (FIG. 1). 12) can be prevented from being irradiated with ultraviolet rays.

  Since the present invention can be protected from ultraviolet rays, it can also be placed in a place where it may be exposed to ultraviolet rays. Therefore, it can be applied to the indoor wiring of the optical cord.

It is a schematic diagram which shows the 1st form of the optical cord which concerns on this embodiment. It is a cross-sectional view of an optical cord, (a) shows an A-A 'cross section, (b) shows a B-B' cross section. It is a cross-sectional view showing a specific example of an optical cord. It is a schematic diagram which shows an example of a core wire contrast. It is a 2nd form of an optical cord, (a) is a schematic diagram, (b) is C-C 'sectional drawing. It is a schematic diagram which shows the 3rd form of an optical cord. It is a 4th form of an optical code, (a) is a schematic diagram, (b) is D-D 'sectional drawing. It is a 5th form of an optical cord, (a) is a mimetic diagram, (b) is an E-E 'sectional view. It is a schematic diagram which shows the 6th form of an optical cord. It is a schematic diagram which shows the 7th form of an optical cord. It is an 8th form of an optical code, (a) is a schematic diagram, (b) is F-F 'sectional drawing. It is the schematic diagram which showed an example of the operation | work of core wire contrast.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Optical fiber 12 Resin layer 13 Ultraviolet ray prevention layer 14 Leakage window 15, 16, 17 Light-shielding cover 21 Cylindrical body 22 Connection part 31 Transmission window 32 Slit 51 Core 52 Cladding 53 Buffer layer 54 Covering 55 Reinforcement material 56 Sheaths 91, 92, 93, 94, 95, 96, 97, 98, 200 Optical code H, I, J Movement direction of light shielding cover 101 Control light 102 Light receiving element 211 OLT
212 Light source 213 Optical coupler 214 Optical fiber 215 Bending part 216 ONU
220 Base station 221 Intermediate point 222 Subscriber's house 223 Receiver

Claims (6)

An optical fiber that propagates light;
A resin layer covering a side surface of the optical fiber and transmitting light of a specific wavelength propagating through the optical fiber;
An ultraviolet ray prevention layer that covers the outer periphery of the resin layer and prevents the resin layer from being irradiated with ultraviolet rays from the outside;
A leakage window that leaks the light of the specific wavelength to the outside of the ultraviolet prevention layer by removing a part of the ultraviolet prevention layer,
A light-shielding cover that covers the leakage window, prevents external ultraviolet irradiation to the leakage window, and can expose the leakage window by moving;
An optical cord comprising: The light shielding cover is a cylindrical body that surrounds the outer periphery of the ultraviolet protection layer,
By the tubular body moves in the longitudinal direction of the optical fiber, optical cord according to claim 1, wherein the leakage windows are exposed. The light-shielding cover is a semi-cylindrical body that covers a part of the circumferential direction of the outer periphery of the ultraviolet protection layer,
Wherein by semicylindrical body moves in the longitudinal direction of the optical fiber, optical cord according to claim 1, wherein the leakage windows are exposed. The light-shielding cover is a semi-cylindrical body that covers a part of the circumferential direction of the outer periphery of the ultraviolet protection layer,
Wherein by semicylindrical body rotationally moves around axis in the longitudinal direction of the optical fiber, optical cord according to claim 1, wherein the leakage windows are exposed. A connection part for connecting one end of the light-shielding cover to the ultraviolet ray prevention layer;
Said that the other end of the light-shielding cover is rotationally moved, the optical cord according to claim 1, wherein the leakage windows exposing the connecting portion as a fulcrum. The optical cord according to any one of claims 1 to 5 , wherein the leakage window is provided so as to cover a part of a circumferential direction of the outer periphery of the resin layer.

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