JP2011145217A - Hot-line detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot-line detector in which the effect on an optical signal is suppressed. <P>SOLUTION: A hot-line detector has an optical connection part 1 which contains: a first optical waveguide 11 connecting two optical lines formed from an optical fiber 5; and a second optical waveguide 12 having a core diameter smaller than the first optical waveguide 11, and formed to cross the first optical waveguide 11, for taking out a part of the signal light transmitted through the first optical waveguide 11. It also has a photodetecting part 2 which detects the signal light taken out by the second optical waveguide 12. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a live line detection device that detects whether or not an optical line formed by an optical fiber is in a live line state (a state in which light is normally transmitted through the optical line).

  2. Description of the Related Art Conventionally, there has been provided a live line detector that detects whether or not an optical line formed by an optical fiber is in a live line state (see, for example, Patent Document 1). This hot-line detector includes a modulation mechanism that modulates an optical signal by applying bending deformation to an optical fiber, and first and second detection mechanisms that are each provided with a light receiving element and are arranged on both sides of the modulation mechanism. When the optical fiber is bent and deformed by the modulation mechanism, a part of the optical signal propagating in the optical fiber leaks outside from the bent portion, so that the light receiving element receives this leaked light. Thus, the presence or absence of an optical signal can be detected. Then, when the leak light can be received by the light receiving element, it is determined that the optical line is in a live line state, and when it is not received, it is determined that the light line is not in a live line state.

Japanese Patent Laid-Open No. 10-246818 (paragraph [0016] and FIG. 1)

  In the live line detector shown in the above-mentioned Patent Document 1, it is determined whether or not the optical line is in the live line state based on the optical signal leaking from the bent portion of the optical fiber. When bent, the amount of light leaking from the bent portion increases, which may increase the effect on the optical signal.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a hot-wire detection apparatus that suppresses the influence on an optical signal.

  The invention of claim 1 is a hot-wire detection device that detects whether or not an optical line formed by an optical fiber is in a live-line state, and has a first optical waveguide that connects two optical lines. A second optical waveguide having a core diameter smaller than that of the first optical waveguide and intersecting the first optical waveguide, and extracting a part of the signal light transmitted through the first optical waveguide. And an optical detection unit that detects the signal light extracted by the second optical waveguide.

  According to a second aspect of the present invention, in the first aspect of the invention, the optical fiber has a core made of quartz glass, and the first and second optical waveguides are formed by irradiating the ultraviolet curable resin with ultraviolet rays. It is an optical waveguide.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the light detection unit includes a light receiving element that receives the signal light extracted by the second optical waveguide, and the light receiving element and the second optical waveguide. And an optical fiber disposed between them to guide the signal light to the light receiving element.

  According to the first aspect of the present invention, the second optical waveguide is formed so that the core diameter is smaller than that of the first optical waveguide and intersects the first optical waveguide. The mode signal light is extracted to the second optical waveguide side, and as a result, the effect on the optical signal can be suppressed. In addition, since light leakage is transmitted through the second optical waveguide, there is an effect that the loss of light leakage detected by the light detection unit can be suppressed.

  According to the second aspect of the present invention, since the core of the optical fiber is formed of quartz glass, an optical fiber excellent in ultraviolet transmission can be realized, and the first and second optical fibers can be simply irradiated with ultraviolet rays. The optical waveguide can be easily formed.

  According to the invention of claim 3, the optical fiber is arranged between the second optical waveguide and the light receiving element, and the arrangement of the light receiving element can be arbitrarily set by adjusting the length of the optical fiber. There is an effect that can be done.

It is a schematic block diagram of the hot-wire detection apparatus of this embodiment. It is a schematic block diagram which shows the other example same as the above.

  An embodiment of a hot-wire detection apparatus according to the present invention will be described with reference to the drawings. The hot-wire detection apparatus according to the present invention is used to detect whether or not an optical line formed by an optical fiber is in a hot-wire state (a state where light is normally transmitted through the optical line).

  FIG. 1 is a schematic configuration diagram of a live line detection apparatus according to the present embodiment. The live line detection apparatus includes an optical connection unit 1 and a photo detection unit 2 as main components.

  As shown in FIG. 1, the optical connection unit 1 includes a first optical waveguide 11 that connects two optical lines formed by the optical fiber 5, and signal light transmitted through the first optical waveguide 11. A second optical waveguide 12 for extracting a part (leakage light P3 in FIG. 1). The second optical waveguide 12 has a core diameter smaller than that of the first optical waveguide 11 and the first optical waveguide. It is provided so as to be orthogonal to the waveguide 11. Here, the first and second optical waveguides 11 and 12 are self-forming optical waveguides (waveguide structures formed spontaneously by irradiating light in a photosensitive medium). The first and second optical waveguides 11 and 12 are formed by irradiating the ultraviolet curable resin with ultraviolet rays.

  Note that the core diameter of the first optical waveguide 11 is set to be approximately the same as the core diameter of the core 51 of the optical fiber 5 forming the optical line, and the core diameter of the second optical waveguide 12 is the optical diameter described later. The diameter is set to be approximately the same as the core diameter of the core 31 of the optical fiber 3 constituting the detection unit 2. The ratio of the core diameters of the first optical waveguide 11 and the second optical waveguide 12 is appropriately set based on, for example, characteristics of signal light transmitted through the optical line, sensitivity of the light receiving element 4 described later, and the like.

  As shown in FIG. 1, the light detection unit 2 includes a light receiving element 4 (for example, a photodiode) that receives signal light (leakage light P3 in FIG. 1) extracted by the second optical waveguide 12, and the light receiving element. 4 and an optical fiber 3 that guides the signal light to the light receiving element 4 and is arranged between the second optical waveguide 12 and the second optical waveguide 12. In this embodiment, the second optical waveguide 12 is formed in the vertical direction. Photodetectors 2 are provided at both ends, respectively. The light receiving element 4 is configured to output a signal corresponding to the amount of received light.

  Further, the hot-line detection device of the present embodiment includes a determination circuit (not shown) using a comparator. In this determination circuit, when the signal input from the light receiving element 4 exceeds a predetermined reference value. A predetermined drive signal is output. Then, a light emitting diode (not shown) is turned on by this drive signal to indicate that the optical line is in a live line state.

  Here, the optical fibers 3 and 5 of this embodiment take into consideration environment resistance such as propagation loss, transmission bandwidth and mechanical strength, and that the light used for forming the self-forming optical waveguide is ultraviolet light. Considering, cores 31 and 51 made of quartz glass are used.

  Next, a method for forming the optical connecting portion 1 will be described. First, optical fibers 3 and 3 for detecting light leakage are arranged on both sides in the vertical direction of a mold (not shown) containing an ultraviolet curable resin, and optical fibers 5 are formed on both sides in the horizontal direction of the mold. 5 is arranged. And after irradiating an ultraviolet-ray from the opening end side of the four optical fibers 3 and 5 and forming the 1st and 2nd optical waveguides 11 and 12, the uncured ultraviolet curable resin is removed from a shaping | molding die. . Finally, when the mold 13 is filled with the resin 13 and cured, the optical connecting portion 1 shown in FIG. 1 can be molded. The resin 13 covering the first and second optical waveguides 11 and 12 needs to be selected so as to have a refractive index smaller than that of the ultraviolet curable resin so as to reduce the propagation loss.

  Next, the operation of the live line detection device will be described. The signal light P1 to be transmitted through the left optical line (optical fiber 5) in FIG. 1 and the higher-order mode component P2 of the signal light P1 pass through the first optical waveguide 11, and the right optical line (in FIG. At this time, a part of the higher-order mode component P2 of the signal light P1 passing through the first optical waveguide 11 is extracted to the second optical waveguide 12 side as leakage light P3. It is. The leaked light P3 taken out to the second optical waveguide 12 enters the light receiving element 4 through the optical fiber 3, and the light receiving element 4 outputs a signal corresponding to the amount of the leaked light P3. When this signal is input to the discrimination circuit, the discrimination circuit outputs a predetermined drive signal because this signal exceeds the reference value, and the light emitting diode is turned on by this drive signal, and the optical line is in a live line state. It is displayed.

  On the other hand, when the signal output from the light receiving element 4 is below the reference value, the discriminating circuit does not output the drive signal, so the light emitting diode is not lit and the optical line is not in a live state. It is.

  Thus, according to the present embodiment, the second optical waveguide 12 is formed so that the core diameter is smaller than that of the first optical waveguide 11 and intersects the first optical waveguide 11. High-order mode signal light (leakage light P3) that is not used for the light is extracted to the second optical waveguide 12 side, and as a result, the influence on the optical signal can be suppressed. Further, since the leakage light P3 is transmitted through the second optical waveguide 12, the loss of the leakage light P3 detected by the light detection unit 2 can be suppressed.

  Furthermore, since the cores 31 and 51 of the optical fibers 3 and 5 are made of quartz glass, the optical fibers 3 and 5 excellent in ultraviolet transmission can be realized, and the first and The second optical waveguides 11 and 12 can be easily formed. Further, the optical fiber 3 is arranged between the second optical waveguide 12 and the light receiving element 4, and the arrangement of the light receiving element 4 can be arbitrarily set by adjusting the length of the optical fiber 3.

  In this embodiment, the case where the light detection units (the optical fiber 3 and the light receiving element 4) 2 are provided at both ends of the second optical waveguide 12 has been described as an example, but the light detection unit 2 is configured as shown in FIG. What is necessary is just to be provided in the end of the 2nd optical waveguide 12, and what is necessary is just to arrange | position the reflective mirror 6 which reflects the light leakage P3 to the photon detection part 2 side at the other end. In the present embodiment, the optical detection unit 2 is configured by the optical fiber 3 and the light receiving element 4, but the optical detection unit 2 may be configured by only the light receiving element 4. What is necessary is just to connect to the optical waveguide 12 directly.

DESCRIPTION OF SYMBOLS 1 Optical connection part 2 Optical detection part 5 Optical fiber 11 1st optical waveguide 12 2nd optical waveguide

Claims (3)

  A hot-line detection device that detects whether or not an optical line formed by an optical fiber is in a live-line state, having a first optical waveguide connecting between two optical lines, and having a first core diameter An optical connection portion having a second optical waveguide that is smaller than the optical waveguide and intersects the first optical waveguide and takes out part of the signal light transmitted through the first optical waveguide; And a light detector for detecting signal light extracted by the two optical waveguides.   2. The optical fiber has a core made of quartz glass, and the first and second optical waveguides are self-forming optical waveguides formed by irradiating ultraviolet curable resin with ultraviolet rays. The hot-wire detection apparatus as described.   The light detection unit is disposed between a light receiving element that receives the signal light extracted by the second optical waveguide, and the light receiving element and the second optical waveguide, and the signal light is transmitted to the light receiving element. The hot-wire detection apparatus according to claim 1, further comprising a guiding optical fiber.

Images