JP5392914B2 - Optical fiber measuring device - Google Patents

Description

  The present invention relates to a core wire contrast technique for specifying an optical fiber and an OTDR (Optical Time Domain Reflectometer) technique for evaluating an optical fiber.

  In recent years, with the increase in optical access services and the expansion of the optical service area, the amount of optical facilities has increased, and there has been an increase in obstruction relocation works that change cable routes associated with road construction and the like. In obstacle relocation work, after laying the cable at the relocation destination outdoors, identify the optical fiber as the relocation source, cut the core wire and switch the core wire to connect with the relocation target optical fiber, and test whether it is connected correctly (For example, refer nonpatent literature 1).

On the other hand, a core wire contrast technique for specifying an optical fiber has been proposed (for example, see Non-Patent Document 2). In Non-Patent Document 2 core control technology, as shown in FIG. 16, it is inserted from the communication facility building 91, the modulated light L _K modulated from the long wavelength side wavelength of communication light L _S to the optical fiber 100. Outdoor communications facilities building 91, bending the optical fiber 100 to the extent that the modulated light L _K leaks, determines the presence or absence of modulated light L _K from leaking light. Thus, without affecting the communication light L _S of the optical fiber 100, to identify the optical fiber 100 by inserting the modulated light L _K.

Masahito Ari, Yuji Higashi, Tomotaka Enomoto, Katsaki Suzuki, Noriyuki Araki, Shigenori Uruno, Tsuneichi Watanabe, “Optical Media Network Operation Technology to Support the Expanding Optical Access Network”, NTT Technology Journal, December 2006, pp . 58-61 Suzuki Katsuaki, Yamamoto Motoshi, Natsume Arata, “Optical Fiber Contrast Technology for R15 Core”, NTT Technical Journal, April 2007, pp. 54-55

  When carrying out optical cable switching work such as obstacle relocation work, identification of the optical fiber to be switched by core wire control, cutting of the target optical fiber, confirmation of disconnection by OTDR measurement, connection to the destination optical fiber, transfer by OTDR measurement The work procedure is to confirm the connection of the optical fiber.

  As shown in FIG. 17, an optical coupler 56 is installed in the communication facility building 91, an OLT (Optical Line Terminal) 51 is connected to the α port of the optical coupler 56, and a communication facility building is connected to the γ port. 91 is connected to an optical fiber 100 extending outside. The modulation light source 54 or the OTDR measurement device 53 is connected to the β port of the optical coupler 56. Incident light from the β port of the optical coupler 56 is not emitted to the α port, but is emitted only to the γ port. Incident light to the γ port is emitted to the α and β ports. Thereby, a core line contrast and OTDR measurement can be performed without cutting the communication line.

However, as shown in FIG. 17, the time of performing the wire control to connect the modulated light source 54 for generating the modulated light L _K in the optical fiber 100 to the β port, the optical fiber 100 to the β port when performing OTDR measurements It is necessary to connect the OTDR measurement device 53 to the OTDR.

  As described above, since the core wire control and the OTDR measurement use different devices, the worker in the communication facility building 91 communicates with the outdoor worker by telephone or the like, and the β of the optical coupler 56 according to the work situation. The device connected to the port was exchanged. For this reason, when carrying out the optical cable switching work such as the obstacle relocation work, it is necessary for the worker to always stand by in the communication equipment building 91.

Also, the trouble relocation work for working simultaneously 2 or more points P _X and the point P _Y outdoors, for example, the point P _X in OTDR measurements, you may wish to point P _Y in wire control. In such a case, since the OTDR measurement and the core line control cannot be performed at the same time, it is necessary to interrupt one of the operations. For this reason, the work time for trouble relocation work becomes longer, and there is a problem that the service interruption time associated with switching becomes longer.

  Therefore, an object of the present invention is to provide an optical fiber measuring device, an optical fiber measuring system, and an optical fiber measuring method capable of simultaneously performing OTDR measurement and core line contrast.

  In order to achieve the above object, an optical fiber measurement device, an optical fiber measurement system, and an optical fiber measurement method according to the present invention use a multiplexed light obtained by combining modulated light for core wire contrast and pulse light for OTDR measurement. It outputs to an optical fiber.

Specifically, in the optical fiber measurement device of the present invention, the optical output unit that generates the combined light in which the modulated light and the pulsed light are superimposed, and the pulsed light generated by the optical output unit is reflected by the optical fiber. A light receiving unit that receives the return light, and an arithmetic unit that measures the amount of return light received by the light receiving unit and the time from when the pulsed light is output to the optical fiber until the return light is received. The wavelength of the modulated light and the wavelength of the pulsed light are the same, and the light intensity of the modulated light is smaller than the light intensity of the pulsed light .

  Since the combined light includes the modulated light, the optical fiber core line can be compared. Since the combined light includes pulsed light, the light receiving unit receives the return light, and the arithmetic unit measures the time from when the pulsed light is output to the optical fiber until the return light is received, thereby performing OTDR measurement. be able to. Therefore, the optical fiber measurement device of the present invention can simultaneously perform OTDR measurement and core wire contrast.

Core wire control can be performed even at low modulated light wave height value. On the other hand, in order to perform OTDR measurement, pulse light having a high peak value is required. Therefore, noise in the OTDR measurement can be reduced by making the light intensity of the modulated light smaller than the light intensity of the pulsed light.

In the optical fiber measurement device of the present invention, the light output unit includes a modulated light generation unit that generates the modulated light, a pulsed light generation unit that generates the pulsed light, the modulated light from the modulated light generation unit, and And a multiplexing unit that multiplexes the pulsed light from the pulsed light generation unit.
According to the present invention, it is possible to generate combined light in which modulated light and pulsed light are superimposed.

In the optical fiber measurement device according to the present invention, the light output unit includes a continuous light generating unit that generates continuous light, and a modulation signal having a waveform in which the modulated light and the pulsed light are superimposed, from the continuous light generating unit. And a modulation unit that modulates the continuous light.
According to the present invention, it is possible to generate combined light in which modulated light and pulsed light are superimposed. Further, the combined light can be generated with one light source, and the combined portion can be omitted, so that the light output portion can be realized with a simple configuration.

In the optical fiber measurement device according to the present invention, the interval between the pulse lights of the combined light may be a time during which light propagates a distance that is at least four times the length of the optical fiber.
According to the present invention, return light behaves like pulsed light in an optical fiber and can be prevented from being superimposed on an OTDR waveform.

  Specifically, an optical fiber measurement system according to the present invention includes an optical fiber measurement device according to the present invention and the combined light from the optical fiber measurement device inserted into the optical fiber and reflected by the optical fiber. An optical multiplexer / demultiplexer for separating the return light into the optical fiber measuring device; and a modulated light receiver for receiving the modulated light leaking from the outer sheath of the optical fiber.

  Since the optical multiplexer / demultiplexer is provided, the combined light can be inserted into the optical fiber, and the return light from the optical fiber can be separated into the optical fiber measuring device. Since the combined light includes the modulated light, the optical fiber core line can be compared using the modulated light receiver. Since the multiplexed light includes pulsed light, the return light can be received and OTDR measurement can be performed. Therefore, the optical fiber measurement system of the present invention can simultaneously perform OTDR measurement and core line contrast.

  Specifically, in the optical fiber measurement method of the present invention, a combined light output procedure for continuously inputting the combined light in which the modulated light and the pulsed light are superposed on one end of the optical fiber, and an arbitrary optical fiber A modulated light detection procedure for receiving the modulated light combined with the combined light at a position; and the optical fiber that has received the modulated light in the modulated light detection procedure is cut in the middle of the optical fiber; The pulsed light out of the combined light output in the wave light output procedure is reflected by the optical fiber and receives the return light returned to the one end of the optical fiber, and determines whether or not the optical fiber is cut. An optical fiber cutting procedure and an optical fiber close to the one end of the optical fibers cut by the optical fiber cutting procedure are connected to another optical fiber, and the combined light output by the combined light output procedure The pulsed light is receiving the return light returned to said one end of said optical fiber is reflected by the optical fiber, having a fiber connection procedure determines whether the optical fiber is connected in this order.

  Since the combined light includes the modulated light, the optical fiber core line can be compared. Since the multiplexed light includes pulsed light, the return light can be received and OTDR measurement can be performed. Therefore, the optical fiber measurement method of the present invention can simultaneously perform OTDR measurement and core wire contrast.

In the optical fiber measurement method of the present invention, the intensity of the modulated light is smaller than the intensity of the pulsed light.
The core wire contrast can be performed even with modulated light having a low peak value. On the other hand, in order to perform OTDR measurement, pulse light having a high peak value is required. Therefore, noise in the OTDR measurement can be reduced by making the light intensity of the modulated light smaller than the light intensity of the pulsed light.

In the optical fiber measurement method of the present invention, in the combined light output procedure, the modulated light and the pulsed light may be generated, and the modulated light and the pulsed light may be combined.
According to the present invention, it is possible to generate combined light in which modulated light and pulsed light are superimposed.

In the optical fiber measurement method of the present invention, in the combined light output procedure, continuous light may be generated, and the continuous light may be modulated with a modulation signal having a waveform in which the modulated light and the pulsed light are superimposed.
According to the present invention, it is possible to generate combined light in which modulated light and pulsed light are superimposed. Further, since the combined light can be generated with one light source, the combined light can be generated with a simple configuration.

In the optical fiber measurement method of the present invention, the interval between the pulsed lights of the combined light may be a time during which light propagates a distance that is at least four times the length of the optical fiber.
According to the present invention, return light behaves like pulsed light in an optical fiber and can be prevented from being superimposed on an OTDR waveform.

  The above inventions can be combined as much as possible.

  According to the present invention, it is possible to provide an optical fiber measurement device, an optical fiber measurement system, and an optical fiber measurement method capable of simultaneously performing OTDR measurement and core line contrast.

An example of the structure of the optical fiber measurement system which concerns on this embodiment is shown. The 1st example of a light output part is shown. The 2nd example of a light output part is shown. Is an example of a light waveform generated optical output, (a) shows the waveform of the pulse light L _P, (b) shows the waveform of the modulated light L _K, (c) the waveform of the multiplexed light L _F Indicates. It shows another embodiment of the waveform of the multiplexed light L _F. It is a flowchart which shows an example of the optical fiber measuring method which concerns on this embodiment. The state of the optical fiber measurement system in combined light output procedure S101 is shown. An example of an OTDR measuring apparatus is shown. An example of the OTDR waveform in the combined light output procedure S101 is shown. It shows the state of the optical fiber measurement system when the optical fiber 100a is cut at the point P _Y. It shows an example of OTDR waveform when the optical fiber 100a is cut at the point _{P Y.} It shows the state of the optical fiber measurement system when the optical fiber 100a is cut at the point P _X. It shows an example of OTDR waveform when the optical fiber 100a is cut at the point _{P X.} The state of the optical fiber measurement system in optical fiber connection procedure S104 is shown. An example of the OTDR waveform in optical fiber connection procedure S104 is shown. It is explanatory drawing which shows an example of the conventional core wire contrast technique. An example of the structure of the conventional optical fiber measurement system is shown.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. In the present specification and drawings, the same reference numerals denote the same components.

  FIG. 1 shows an example of the configuration of an optical fiber measurement system according to this embodiment. The optical fiber measurement system according to this embodiment includes an optical fiber measurement device 11, an optical multiplexer / demultiplexer 12, a modulated light receiver 13, and a reflection filter 14.

Optical fiber measuring device 11 receives the modulated light _{L K} and the multiplexed light _{L F} of the pulsed light _{L P} are superposed and outputted to the optical fiber 100a, the pulse light _{L P} is reflected by the optical fiber 100a returning light _{L B} To do. Demultiplexer 12, is inserted the combined light L _F from the optical fiber measuring device 11 to the optical fiber 100a, separates the reflected by the optical fiber 100a returning light L _B in the optical fiber measuring device 11. Modulated light receiving unit 13 receives the modulated light _{L K} leaking from the outer skin of the optical fiber 100a. Reflection filter 14 is installed at the ends of the ONU (Optical Network Unit) side of the optical fiber 100a, and reflects the pulse light _{L P.} When the pulse light L _P reaches the reflective filter 14, reflected light of the reflection filter 14 becomes return light L _B by the Fresnel reflection.

Because it contains modulated light L _K in multiplexed light L _F, it is possible to perform the core control using modulated light photodetector 13. Since the multiplexed light L _F contains pulse light L _P, it is possible to perform OTDR measurements by receiving the return light L _B in the optical fiber measuring device 11. Therefore, the optical fiber measurement system according to the present embodiment can simultaneously perform OTDR measurement and core line contrast.

The optical fiber measurement device 11 includes a light output unit 21, a light receiving unit 22, and a calculation unit 23. The light output unit 21 generates a combined light _{L F} modulated light _{L K} and the pulse light _{L P} are superimposed. Here, the light intensity of the modulated light L _K is smaller than the light intensity of the pulsed light L _P. Wavelength of the modulated light _{L K} and the pulse light _{L P} is different from the communication light _{L S.} Wavelength of the pulse light L _P of the modulated light L _K may be the same or different.

Receiving unit 22, pulse light _{L P} generated by the optical output unit 21 receives the returning light _{L B} reflected by the optical fiber 100a. Receiving unit 22, similarly to the conventional OTDR measuring device, received in accordance with the output to the period of the pulsed light L _P. Calculation unit 23 measures the time until the light quantity and the pulse light L _P of the return light L _B for receiving the light-receiving unit 22 receives the returning light L _B from the output of the optical fiber 100a. Thereby, the optical fiber measuring device 11 performs OTDR measurement.

FIG. 2 shows a first example of the light output unit. The first example of the light output unit includes a modulated light generation unit 31, a pulsed light generation unit 32, and a multiplexing unit 33. Modulated light generating unit 31 generates the modulated light _{L K.} Pulsed light generation unit 32 generates a pulse light _{L P.} Multiplexing section 33 multiplexes the pulse light L _P from the modulated light L _K and the pulse light generating portion 32 from the modulated light generating unit 31. Thus, from the multiplexing unit 33, the multiplexed light _{L F} is output.

FIG. 3 shows a second example of the light output unit. The second example of the light output unit includes a continuous light generation unit 34, a modulation signal generation unit 36, and a modulation unit 35. Continuous light generating unit 34 generates a continuous light _{L C.} Modulation signal generator 36 generates a modulated signal S _K having a waveform modulated light L _K and the pulse light L _P are superimposed. Modulator 35 is a modulated signal S _K from the modulation signal generator 36, modulates the continuous light L _C from the continuous light generating unit 34. Thus, the modulation unit 35, the multiplexed light _{L F} is output. By adopting this configuration, it is possible to simultaneously emit the modulated light L _K and the pulse light L _P using the same continuous light generation unit 34. In this configuration, since the multiplexing unit is not necessary, the configuration can be simplified.

Figure 4 is an example of a light waveform generated optical output, (a) shows the waveform of the pulse light L _P, (b) shows the waveform of the modulated light L _K, (c) the combined light It shows the waveform of the L _F. 4A, 4B, and 4C, the vertical axis represents the output level and the horizontal axis represents time. By multiplexing unit 33 multiplexes the modulated light L _K and the pulse light L _P, and outputs the multiplexed light L _F having the waveform shown in FIG. 4 (c).

OTDR measurement to observe the Rayleigh scattering level generated in the optical fiber at the time of the incident pulse light L _P to the optical fiber 100a, it is necessary to generate a strong pulse light of power. For this reason, it is preferable that peak power is +10 dB or more. On the other hand, the peak power of the modulated light L _K for wire control may be about -5 dB. Therefore, it is preferable that a difference of more than 15dB from the optical power of the pulse light L _P and the optical power of the modulated light L _K.

In OTDR measurement, pulsed light L _P from the optical output unit 21 emits, by the Rayleigh scattering light generated in the optical fiber 100a observes and received by the light receiving unit 22, the loss or the connection with a optical fiber 100a interval Measure the point loss. Further, Fresnel reflection occurs from the refractive index difference at the connection point, and the amount of reflection at the connection point can be observed. Receiving unit 22, a return light L _B of the Rayleigh scattered light and Fresnel reflection light or the like generated in the optical fiber 100a is measured, the arithmetic unit 23 calculates the distance in time to the return light L _B returns . Therefore, so as not to overlap the return light L _B from different pulse light L _P, the period of outputting the pulse light L _P is twice the time pulse light L _P is transmitted through the optical fiber 100a (time to reciprocating) That's it.

On the other hand, when the core wire controls, bending the optical fiber 100a at the point P _X and the point P _Y is added, the core wire of the plan of the modulated light L _K leaked from the optical fiber 100a receives a modulated optical light receiver 13 is cut That is, the optical fiber 100a is specified.

Since the modulated light L _K in performing core control small incidence level to the optical fiber 100a than the OTDR measurement, the influence of Rayleigh scattering which occurs in the optical fiber 100a is small. Fresnel reflection occurs due modulated light L _K in the connection point with connectors or mechanical splices. However, the return loss of the common connector for of the order of 40 dB, if the peak power -5dB of the modulated light L _K, light incident on the light-receiving portion 22 is -55dB about be larger.

However, in the optical line section composed of the optical fiber 100a to be measured, there is a place where the connector is incompletely fitted in the half-inserted state, or there is a place where the optical fiber such as an optical splitter is branched. In this case, since the return loss is about 15 dB, reflected light close to −22 dB enters the light receiving unit 22. In this case, the reflected light becomes a noise of the modulated light _{L K,} overlap OTDR waveform, there is a possibility that the OTDR waveform disturbed.

Therefore, in the OTDR measurement, the light reception level can be increased by widening the pulse width, and the dynamic range is expanded. Further, the modulated light L _K is back reflected light is continuously generated, the time until the reflected light by the modulated light L _K is back is not always coincide with the length of the optical fiber 100a. Therefore, by performing addition averaging during OTDR measurement, it is possible to reduce the noise generated by light reflected modulated light L _K.

Although the modulated light _{L K} for core control a square wave mainly 270 Hz, pulse wave _{L P} used for OTDR measurements thin and 1000ns from 10 ns, the pulse emission period, the pulse light _{L P} is the optical fiber 100a because of twice the time to transmit at least three times, it receives the majority of the modulated light L _K, it is possible to perform the core wire control.

Figure 5 shows another embodiment of the waveform of the multiplexed light L _F. The interval T _P between the pulsed light L _P -1 and the pulsed light L _P -2 of the combined light L _F is a time for light to propagate a distance that is four times or more the length of the optical fiber 100a. Interval T _P is generally the spacing or 4 times the time pulse light L _P to transmit distance range, the time pulse light L _P is 2 reciprocating above the optical fiber 100a. As a result, the Fresnel reflection generated at the far end of the optical fiber 100a returns to the optical fiber measurement device 11 side, is reflected again by the connector of the optical output unit 21, and is not superimposed on the OTDR waveform like a ghost. Can do.

In addition, after outputting the modulated light L _K −1 and the pulsed light L _P −1, the modulated light L _K −2 starts to be output after the time twice as long as the distance range has passed, and the next pulsed light L _P −2 is output. Until the modulated light L _K -2 is output.

  FIG. 6 is a flowchart illustrating an example of an optical fiber measurement method according to the present embodiment. The optical fiber measurement method according to the present embodiment includes a multiplexed light output procedure S101, a modulated light detection procedure S102, an optical fiber cutting procedure S103, and an optical fiber connection procedure S104 in this order.

In the multiplexed light output procedure S101 shown in FIG. 6, the multiplexed light _{L F} modulated light _{L K} and the pulse light _{L P} are superimposed, is input to one end of the continuous optical fiber 100a. The output of the multiplexed light _{L F} is modulated light detection procedure S102, over the optical fiber cutting steps S103 and optical fiber connection procedure S104, continuously performed.

The output of the multiplexed light L _F is, for example, by using the first example of the light output section 21 shown in FIG. 2, it generates a pulse light L _P as well as generate a modulated light L _K, modulated light L _K and pulse light L _P is combined. Further, by using the second example of the light output section 21 shown in FIG. 3, it generates a continuous light L _C, continuous light L in modulated signal S _K having a waveform modulated light L _K and the pulse light L _P are superposed _C may be modulated.

FIG. 7 shows the state of the optical fiber measurement system in the combined light output procedure S101. In the optical fiber measurement system shown in FIG. 7, the optical output unit 21 includes an OTDR measurement device 53, a modulation light source 54, and an optical coupler 55. OTDR measurement device 53 outputs the pulse light _{L P} to the optical coupler 55, and by receiving the return light _{L B} from the optical coupler 55, performs OTDR measurement. Modulated light source 54 outputs a modulated light _{L K} to the optical coupler 55. The modulated light source 54 functions as the modulated light generator 31 shown in FIG. The optical coupler 55 functions as the multiplexing unit 33 shown in FIG.

FIG. 8 shows an example of an OTDR measurement device. OTDR measuring apparatus 53 shown in FIG. 8 includes a LD (Laser Diode) 61 for generating a pulse light _{L P,} and APD (Avalanche PhotoDiode) 62 for receiving the return light _{L B,} and the optical directional coupler 63, the . The LD 61 functions as the pulsed light generator 32 shown in FIG. The APD 62 functions as the light receiving unit 22 shown in FIG.

LD61 shown in FIG. 8 may output the multiplexed light _{L F} that shown in FIG. 4 (c) or FIG. In this case, the modulation light source 54 shown in FIG. 7 can be omitted by modulating the drive unit of the LD 61 with the modulation signal shown in FIG.

The optical coupler 55 includes three ports, the OTDR measuring device 53 is connected to the A port, the modulation light source 54 is connected to the B port, and the β port of the optical multiplexer / demultiplexer 12 is connected to the C port. Yes. The pulsed light L _P incident on the A port is emitted to the C port, the modulated light L _K incident on the B port is emitted to the C port, and the return light L _B incident on the C port is the A port and the B port. Is emitted.

The optical multiplexer / demultiplexer 12 includes three ports, the OLT 51 is connected to the α port, the optical fiber measuring device 11 is connected to the β port, and the optical fiber extending outside the communication facility building 91 is connected to the γ port. 100a is connected. The communication light L _S incident on the α port is emitted to the γ port, the combined light L _F incident on the β port is emitted to the γ port, and the communication light L _S and the return light L _B incident on the γ port are The light is emitted to the α port and the β port.

It outputs a pulse light _{L P} from the OTDR measurement device 53, and outputs the modulated light _{L K} from the modulation light source 54, pulsed light _{L P} and the modulated light _{L K} from OTDR measuring apparatus 53 multiplexes the optical coupler 55, the measurement The light is emitted to the target optical fiber 100a. Pulse light _L P is reflected at a point _{P R} of ONU 52, the reflected return light _{L B} is incident on the γ port of the optical demultiplexer 12. and the return light L _B incident on the γ port is emitted from β port, is incident on the C ports of the optical coupler 55 is emitted from the A port, and enters the OTDR measurement device 53. Then, OTDR measurement device 53 performs the OTDR measurement using the pulsed light _{L P} and the returning light _{L B.}

FIG. 9 shows an example of the OTDR waveform in the combined light output procedure S101. By OTDR measuring device 53 measures the intensity of the returning light L _B, it can be confirmed that the Fresnel reflection occurs at a distance of the point P _R.

In the modulated light detection procedure S102 shown in FIG. 6, for receiving the modulated light L _K which in any position of the optical fiber 100a is multiplexed into multiplexed light L _F. For example, in outdoor locations _{P X} and the point _{P Y,} by bending the optical fiber 100a for receiving the modulated light _{L K} from among the leakage light. Thereby, it is the optical fiber 100a for which the work is performed, or the core wire is compared.

In the optical fiber cutting procedure S103 shown in FIG. 6, to cut the optical fiber 100a which has received the modulated light _{L K} in the modulated light detection procedure S102 in the middle point _{P Y} of the optical fiber 100a. In this case, accidentally while confirming the modulated light L _K in wire control so as not to cut the other optical fiber, cutting the optical fiber 100a.

10 shows a state of the optical fiber measurement system when the optical fiber 100a is cut at the point P _Y. In this state, it receives returned to one end of the optical fiber 100a pulsed light L _P of the multiplexed light L _F output by the multiplexed light output procedure S101 is reflected by the optical fiber 100a return light L _B. Pulse light _{L P} is the Fresnel reflection occurs at the point _{P Y,} the reflected return light _{L B} is incident on the OTDR measurement device 53.

Figure 11 shows an example of OTDR waveform when the optical fiber 100a is cut at the point _{P Y.} When OTDR measurement device 53 measures the intensity of the returning light L _B, Fresnel reflection occurs at a distance of the point P _Y, appears broken waveform. By measuring the Fresnel reflection, it is possible to the optical fiber 100a to determine whether or not cut at a distance of the point P _Y.

In the optical fiber cutting procedure S103 shown in FIG. 6, further cutting the optical fiber 100a which has received the modulated light _{L K} in the modulated light detection procedure S102 in the middle of the point _{P X} of the optical fiber 100a. In this case, accidentally while confirming the modulated light L _K in wire control so as not to cut the other optical fiber, cutting the optical fiber 100a.

12 shows a state of the optical fiber measurement system when the optical fiber 100a is cut at the point P _X. In this state, it receives returned to one end of the optical fiber 100a pulsed light L _P of the multiplexed light L _F output by the multiplexed light output procedure S101 is reflected by the optical fiber 100a return light L _B. Pulse light _{L P} is the Fresnel reflection occurs at the point _{P X,} reflected return light _{L B} is incident on the OTDR measurement device 53.

Figure 13 shows an example of OTDR waveform when the optical fiber 100a is cut at the point _{P X.} When OTDR measurement device 53 measures the intensity of the returning light L _B, Fresnel reflection occurs at a distance of the point P _X, appears broken waveform. By measuring the Fresnel reflection, it is possible to the optical fiber 100a to determine whether or not cut at a distance of the point P _X.

In the optical fiber connection procedure S104 shown in FIG. 6, the optical fiber 100a near the one end on the optical multiplexer / demultiplexer 12 side of the optical fiber 100a cut in the optical fiber cutting procedure S103 is connected to the other optical fiber 100b. For example, to connect the optical fiber 100a to the optical fiber 100b in the optical fiber 100a points were cut _{P X} and the point _{P Y.}

FIG. 14 shows the state of the optical fiber measurement system in the optical fiber connection procedure S104. In this state, it receives returned to one end of the optical fiber 100a pulsed light L _P of the multiplexed light L _F output by the multiplexed light output procedure S101 is reflected by the optical fiber 100a return light L _B. Pulse light _{L P} is the Fresnel reflection occurs at the point _{P R,} the reflected return light _{L B} is incident on the OTDR measurement device 53.

FIG. 15 shows an example of an OTDR waveform in the optical fiber connection procedure S104. By OTDR measuring device 53 measures the intensity of the returning light _{L B,} determines the connection state of point _{P X} and the point _{P Y.} For example, it reads the connection loss of the point P _X and the point P _Y, if the connection loss was prescribed value or less for a predetermined, may be determined to be a normal connection state.

Further, when the OTDR measurement device 53 measures the intensity of the returning light L _B, Fresnel reflection occurs at a distance of a point P _R, it appears broken waveform. By measuring this Fresnel reflection, it can be determined whether or not the optical fiber 100a is connected to the optical fiber 100b.

  According to the present invention, in trouble relocation work, it is not necessary to communicate the work progress sequentially by telephone etc. between the worker in the communication equipment building and the outdoor worker, and it is not necessary to perform the work that matches the timing at multiple work points, Since it is possible to proceed with different tasks, it is possible to reduce the total work time.

In the present embodiment has described the configuration also output in the optical fiber connection procedure S104 modulated light L _K for core control, but is not limited thereto. For example, if it is not necessary to perform wire control after it is confirmed the completion of the cutting operation of the optical fiber 100a at the point P _X, it may stop the output of the modulated light L _K from the modulation light source 54. This eliminates the possible modulated light L _K is incident and reflected at the far end or the like of the connector connecting point and the optical fiber 100a of the optical fiber 100a to the OTDR measurement device 53, reducing the noise superimposed on the OTDR waveform Can do. Therefore, the measurement accuracy in OTDR measurement can be increased.

  The present invention can be used in the information communication industry.

11: Optical fiber measuring device 12: Optical multiplexer / demultiplexer 13: Modulated light receiver 14: Reflective filter 21: Light output unit 22: Light receiving unit 23: Calculation unit 31: Modulated light generating unit 32: Pulsed light generating unit 33: Combined Wave part 34: Continuous light generator 35: Modulator 36: Modulated signal generator 51: OLT
52: ONU
53: OTDR measuring device 54: modulated light source 55: optical coupler 56: optical coupler 57, 58: PD
59: Optical connector 61: LD
62: APD
63: Optical directional coupler 91: Communication equipment building 100, 100a, 100b: Optical fiber

Claims (5)

A light output unit for generating a combined light in which the modulated light and the pulsed light are superimposed;
A light receiving portion for receiving the return light reflected by the optical fiber, the pulsed light generated by the light output portion;
An arithmetic unit that measures the amount of return light received by the light receiving unit and the time from when the pulsed light is output to the optical fiber until the return light is received;
Equipped with a,
The wavelength of the modulated light and the wavelength of the pulsed light are the same,
The light intensity of the modulated light is smaller than the light intensity of the pulsed light
An optical fiber measuring device. The light output unit is
A modulated light generator for generating the modulated light;
A pulsed light generator for generating the pulsed light;
A multiplexing unit that combines the modulated light from the modulated light generation unit and the pulsed light from the pulsed light generation unit;
The optical fiber measuring device according to claim 1 , comprising: The light output unit is
A continuous light generator for generating continuous light;
A modulation unit that modulates the continuous light from the continuous light generation unit with a modulation signal having a waveform in which the modulated light and the pulsed light are superimposed;
The optical fiber measuring device according to claim 1 , comprising: The interval of the pulsed light of the combined light, the optical fiber measured according to any one of claims 1 to 3, characterized in that the distance of more than four times the length of the optical fiber light is time to propagate apparatus. An optical fiber measuring device according to any one of claims 1 to 4 ,
An optical multiplexer / demultiplexer for inserting the multiplexed light from the optical fiber measuring device into the optical fiber and separating the return light reflected by the optical fiber into the optical fiber measuring device;
A modulated light receiver for receiving the modulated light leaking from the outer sheath of the optical fiber;
An optical fiber measurement system comprising:

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