JP4902213B2 - Optical line monitoring apparatus and method - Google Patents

Description

  The present invention relates to an optical line monitoring apparatus and method for monitoring a failure occurring in an optical branch line such as a PON (Passive Optical Network) transmission line connecting between a test apparatus, a splitter, and a termination apparatus.

2. Description of the Related Art Conventionally, as a method for monitoring a branch line using a splitter and a terminating device, a method for confirming an abnormality in an optical line by confirming a change in reflected light intensity of the terminating device is known (Patent Document 1). . In this method, when the measurement is performed with a wide pulse width, the reflected light may overlap when the interval between the reflected lights of the termination device is short. In this case, even if there is a fluctuation in one reflected light intensity, the fluctuation in the reflected light intensity cannot be confirmed due to the reflected light from the other terminal device. Therefore, a short value of about 20 ns or less is used for the pulse width so that the reflected lights do not overlap as much as possible.
In addition to confirming at which end device the abnormality has occurred, it may be desirable to confirm at what distance the abnormality has occurred between the splitter and the termination device. As a general method for detecting an optical line abnormality, there is known a method for identifying a point where a failure has occurred by analyzing a difference between measurement results during normal operation and during failure monitoring. This method can also be used for fault detection between the splitter and the termination device.
Japanese Patent Laid-Open No. 10-170396

When the distance between the termination devices is short, that is, when there is no difference in the distance between each termination device and the test device, it is necessary to perform measurement with a short pulse width in order to prevent the reflected light from overlapping. In this case, if the loss of the optical line is large, there is a problem that the dynamic range is insufficient and noise is generated. In particular, in a branch line using a splitter, a large loss occurs in the splitter. In the case of a noisy waveform, it is difficult to identify the fault occurrence point even if the difference between the measurement results at the normal time and the fault monitoring is confirmed. Further, when automatic determination is performed by software or the like, the probability of erroneous determination becomes very high. If the pulse width is increased in order to suppress the generation of noise, there arises a problem that the reflected light of the termination device overlaps.
In other words, if the terminating device uses an FBG (Fiber Bragg Grating) filter, the reflection level of the filter is large, so that the S / N ratio (Signal to Noise Ratio) is maintained even if the averaging processing time is set relatively short. Although the reflection peak can be detected stably at a large size, reflection from a part other than the filter reflection, for example, a failure occurrence point such as a break point, is buried in noise and may be difficult to distinguish.
However, in order to make a measurement with such a large S / N ratio that the breakage point can be easily identified, for example, it takes about 90 seconds for one measurement. Therefore, it takes a very long time to measure all 100 routes. It will take. Furthermore, since the measurement time per one time is long, it takes a long time to reach the target abnormal route, and there is a problem that it is impossible to cope in an emergency.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to reliably detect the failure of each terminal device and to influence the distance to the point where the failure has occurred by noise. It is an object of the present invention to provide an optical line monitoring apparatus and method that can be obtained accurately without any problems. It is another object of the present invention to provide an optical line monitoring apparatus and method that can accurately and quickly identify the location where a fault point has occurred.

The present invention has been made to solve the above problems, and the invention according to claim 1 is branched from the test apparatus (2) by the splitter (3) and connected to the plurality of termination apparatuses (4). An optical line monitoring device (1) for monitoring a failure of the optical line (f) from the plurality of termination devices for an optical signal emitted by the test device in a state where no failure has occurred in the optical line a first storage means for storing the reflected light intensity (14), a measurement of applying a predetermined averaging time及beauty predetermined pulse width, the measurement of the reflection intensity of the optical signal emitted from the test apparatus a first control means (12) for performing said first control means is a reflection intensity measured, a second memory means for storing the reflected light intensity from the plurality of terminating devices (14), wherein A plurality of termination devices stored in the second storage means; Attenuation amount judging means (12a) for judging whether or not there is a terminating device that is attenuated compared to the reflected light intensity stored in the first storage means, and the reflected light intensity is attenuated. A second control unit for performing the measurement by changing at least one of the predetermined averaging time and the predetermined pulse width when the attenuation amount determining unit determines that there is a terminating device that is present; 12) and an optical line monitoring device.

According to a second aspect of the present invention, the second control means makes the averaging time longer than the predetermined averaging time, or makes the pulse width wider than the predetermined pulse width. The optical line monitoring apparatus according to claim 1, wherein the optical line monitoring apparatus is characterized in that:
According to a third aspect of the present invention, the second control means makes the averaging time longer than the predetermined averaging time and makes the pulse width wider than the predetermined pulse width. The optical line monitoring apparatus according to claim 1, wherein

The invention according to claim 4, wherein as compared with the first waveform of the measurement result by the control means, the second waveform measurements by the control means, whether reflection anomalies are present and third control means for determining (12), when the the reflection abnormality is present the third control means determines, calculates the distance to the point where the abnormality has occurred from the test device The optical line monitoring device according to any one of claims 1 to 3 , further comprising fourth control means (12).

According to a fifth aspect of the present invention, there is provided an optical line connecting the test apparatus and the termination apparatus determined by the attenuation amount determination means that the reflected light intensity is attenuated, and the fourth to fourth test apparatuses. according to any one of claims 1 to 4 in which the control means is further comprising a display means (15) which is what failure at a point at a distance calculated to display whether occurring This is an optical line monitoring device.

The invention according to claim 6 is an optical line for monitoring a failure of the optical line (f) branched from the test apparatus (2) by the splitter (3) and connected to the plurality of termination apparatuses (4). A first step of storing reflected light intensities from the plurality of terminating devices with respect to an optical signal emitted by the test device in a state where no failure has occurred in the optical line, and a predetermined averaging a measurement according to the time及beauty predetermined pulse width, a reflection intensity measured in the second step, the second step for measuring the reflection intensity of the optical signal emitted from the test apparatus, A third step of storing reflected light intensities from the plurality of terminal devices and a reflected light intensity stored in the first step among the reflected light intensities of the plurality of terminal devices stored in the third step. Attenuating termination A fourth step of determining whether there is a location, when the reflected light intensity is determined in the fourth step when there is termination device is attenuated, the predetermined averaging time and the predetermined pulse width And a fifth step of performing the measurement by changing at least one of the optical line monitoring methods.

In the present invention, the reflected light intensity from the plurality of termination devices with respect to the optical signal emitted from the test apparatus in a state where no failure has occurred in the optical line is stored by the first storage means, and the first averaging time and / or Alternatively, an optical signal to which the first pulse width is applied is emitted from the test apparatus by the first control means, and the reflected light intensity from the plurality of termination devices with respect to the optical signal emitted by the first control means is stored in the second storage means. Whether there is a termination device that is attenuated compared to the reflected light intensity stored in the first storage means among the reflected light intensities stored in the second storage means and stored in the second storage means The second averaging time and / or the second pulse width is applied when the attenuation amount determining means determines that there is a terminating device in which the reflected light intensity is attenuated. Optical signal from test device to second control means Ri was to be emitted.
For this reason, by setting the second averaging time longer than the first averaging time and setting the second pulse width wider than the first pulse width, the first average is measured. In the measurement using the activation time and / or the first pulse width, it is possible to distinguish between the terminating devices having close reflection light. Alternatively, it is possible to distinguish between terminating devices having reflected light close to each other with a short averaging time. Further, in the measurement using the second averaging time and / or the second pulse width, the reflected light intensity from the occurrence point such as the termination device or the failure point can be measured without being affected by noise. Therefore, the failure occurrence point on the optical line can be specified with high accuracy.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of an optical line monitoring system according to an embodiment of the present invention. This optical line monitoring system includes an optical line monitoring device 1, a test device 2, a splitter 3, and a termination device 4 (4a to 4d). In the present embodiment, a case where an OTDR (Optical Time Domain Reflectometer) is used as the test apparatus 2 and an ONU (Optical Network Unit) is used as the termination apparatus 4 will be described.
The optical line monitoring device 1 and the test device 2 are connected via a cable c1 such as RS232-C (Recommended Standard 232 version C) and are housed in one housing 1a. One end of the optical line f 1 is connected to the test apparatus 2, and the other end of the optical line f 1 is connected to the connector 5. One end of the optical line f2 is connected to the connector 5, and the other end of the optical line f2 is connected to the splitter 3. Note that the optical line f1 and the optical line f2 may be connected not by the connector 5 but by fusion or the like. Further, one ends of the optical lines f3 to f6 are connected to the splitter 3, and the other ends of the optical lines f3 to f6 are connected to the termination devices 4a to 4d, respectively.
In the present embodiment, optical fibers having lengths of 10 km and 350 m are used as the optical lines f1 and f2, respectively. In addition, optical fibers having lengths of 280 m, 290 m, 300 m, and 310 m were used as the optical lines f3 to f6, respectively.

The optical line monitoring apparatus 1 controls the test apparatus 2 via the cable c1 and acquires information on the waveform of the optical signal measured by the test apparatus 2. The test apparatus 2 emits an optical signal toward the splitter 3 or receives an optical signal emitted from the splitter 3 via the optical line f1 based on the control of the optical line monitoring apparatus 1.
When the splitter 3 receives an optical signal from the test apparatus 2 connected to the upper level, the splitter 3 branches the optical signal with equal power, and emits the optical signal to the terminal apparatuses 4a to 4d connected to the lower level. In addition, when the splitter 3 receives optical signals from the terminal devices 4a to 4d connected to the lower level, the splitter 3 combines the optical signals and outputs them to the test device 2 connected to the higher level. As the splitter 3, for example, a PLC (Planar Lightwave Circuit) type in which optical waveguides are branched in a tree shape on a quartz substrate can be used.
Here, the upper level means a direction in which the test apparatus 2 corresponding to the root of the optical line laid in a tree shape is connected from the test apparatus 2 to the terminal apparatuses 4a to 4d. The term “lower” refers to the direction in which the termination device 4 corresponding to the leaves of the optical line laid in a tree shape is connected from the test apparatus 2 to the termination devices 4a to 4d.

When receiving the optical signal from the splitter 3, the termination device 4 reflects a specific wavelength of the optical signal to the splitter 3. As the termination device 4, for example, an optical connector having a built-in fiber grating filter that reflects an optical signal having a specific wavelength can be used.
In the present embodiment, the case where the terminal devices 4 a to 4 d are connected to the splitter 3 has been described. However, if the number of terminal devices 4 connected to the splitter 3 is equal to or less than the number of branches of the splitter 3, what is the case? It may be a table. Further, in the present embodiment, the case where the terminal devices 4a to 4d are connected to the splitter 3 has been described, but by arranging another splitter between the splitter 3 and the terminal devices 4a to 4d, A multi-stage configuration may be used.

FIG. 2 is a block diagram showing the configuration of the optical line monitoring apparatus 1 according to the present embodiment. The optical line monitoring device 1 includes an input unit 11, a control unit 12 (first to fourth control means), a test device connection unit 13, a storage unit 14 (first and second storage units), and a display unit 15 (display). Means). As the optical line monitoring device 1, a device such as a PC (Personal Computer) is used.
The input unit 11 includes an input device such as a keyboard. Information such as distances and names from the test apparatus 2 to the terminal apparatuses 4a to 4d is input to the input unit 11 by the operation of the administrator of the optical line monitoring system according to the present embodiment.

The control unit 12 controls the input unit 11, the test apparatus connection unit 13, the storage unit 14, and the display unit 15 that constitute the optical line monitoring device 1. The control unit 12 includes an attenuation determination unit 12a (attenuation determination unit), an averaging time setting unit 12b, and a pulse width setting unit 12c.
The attenuation determination unit 12a determines whether or not the intensity of the reflected light from each terminal device 4 is attenuated by analyzing the waveform of the reflected light from each terminal device 4 received by the test apparatus 2.
The averaging time setting unit 12b sets the length of the averaging time of the optical signal emitted from the test apparatus 2. The averaging time means the averaging process time, that is, the number of averaging processes.

The pulse width setting unit 12 c sets the width of the pulse width of the optical signal emitted from the test apparatus 2. If the pulse width is narrow, the distance resolution becomes high, and even if the reflections from the terminal devices 4a to 4d are close to each other, the reflections are difficult to overlap. However, the dynamic range (distance at which measurement accuracy can be maintained) is shortened. On the other hand, when the pulse width is wide, the distance resolution becomes low, and when the reflections from the terminal devices 4a to 4d are close to each other, the reflections overlap. However, the dynamic range becomes longer.
The test apparatus connection unit 13 is connected to the test apparatus 2 via a cable c1 (see FIG. 1). The test apparatus connection unit 13 emits an optical signal from the test apparatus 2 toward the splitter 3 via the optical line f <b> 1 based on the control of the control unit 12. Moreover, the test apparatus connection part 13 acquires the information of the waveform of the reflected light from each termination | terminus apparatus 4 which the test apparatus 2 light-receives via the cable c1.

FIG. 3 is a diagram illustrating an example of information stored in the storage unit 14 according to the present embodiment. As shown in the figure, the storage unit 14 includes a termination device name (such as the termination device 4a), an optical line length (such as 280 m) indicating the distance from the test device 2 to the termination device 4, and the termination device 4 in a normal state. The reflected light intensity (48.0 dB or the like) and the reflected light intensity (48.0 dB or the like) of the termination device 4 at the time of failure monitoring are stored in association with each other.
Here, the normal time means a case where no failure has occurred in the optical line f (f1 to f6). The failure monitoring means that the failure point is detected during periodic inspection after installing the optical line f (f1 to f6) and the termination devices 4a to 4d, or when a failure occurrence is reported (when an alarm is generated). It refers to the case of trying to discover.
When measuring whether or not a fault has occurred.

The information on the termination device name and the information on the optical line length are input from the input unit 11 by the operation of the administrator of the optical line monitoring system according to the present embodiment. Further, the information on the reflected light intensity at the normal time and the information on the reflected light intensity at the time of monitoring the road fault are obtained based on the waveform of the return light received by the test apparatus 2 from each terminal apparatus 4.
The distance from the test apparatus 2 to each terminal apparatus 4 is different. Therefore, since there is a difference in the time from when the optical signal is emitted from the test apparatus 2 to when the reflected light is received, it is specified which reflected light is the reflected light from which terminal device 4 based on the difference in time. can do.

The display unit 15 is configured by a liquid crystal display device or the like. The display unit 15 displays the waveform of the reflected light received from each of the terminal devices 4a to 4d, or displays information on the optical lines f1 to f6 where a failure has occurred.
Next, processing of the optical line monitoring system according to the first embodiment of the present invention will be described.

  FIG. 4 is a flowchart showing a process flow of the optical line monitoring apparatus 1 according to the first embodiment of the present invention. First, the control unit 12 gives an instruction to the test apparatus 2 to emit an optical signal toward the splitter 3 when the optical line f (f1 to f6) is in a normal state where no failure has occurred. The optical signal emitted from the test apparatus 2 is branched by the splitter 3 laid in a tree shape, reflected by the terminal devices 4a to 4d, and returned to the test apparatus 2. The test apparatus connection unit 13 acquires information on the waveform (FIG. 5) of the return light received by the test apparatus 2.

  FIG. 5 is a diagram illustrating an example of a waveform of an optical signal received by the test apparatus 2 in a normal state in the first embodiment of the present invention. The horizontal axis indicates the distance from the test apparatus 2, and the vertical axis indicates the reflected light intensity. In the waveform of FIG. 5, four reflections p1 to p4 occur. These reflections p1 to p4 indicate the reflected lights from the terminal devices 4a to 4d, respectively. Note that the waveform of FIG. 5 was measured under the conditions of an averaging time of 5 seconds and a pulse width of 20 ns.

  The control unit 12 analyzes the waveform (FIG. 5) received by the test apparatus 2, thereby associating the reflected light intensities at the normal times of the reflections p1 to p4 of the termination devices 4a to 4d with the termination device names. 14 (step S01 in FIG. 4). The optical line length can be obtained by reading the value on the horizontal axis where reflection occurs in FIG.

  Also, the manager of the optical line monitoring system according to the present embodiment inputs information on the termination device name and information on the optical line length from the input unit 11. Thereby, the input unit 11 acquires the information on the termination device name and the information on the optical line length (step S02). The control unit 12 stores the termination device name information and the optical line length information acquired by the input unit 11 in association with the storage unit 14 (see FIG. 3).

Returning to FIG. 4, the control unit 12 determines whether or not an instruction for starting failure monitoring of the optical line is input from the input unit 11 (step S <b> 03). If no instruction has been input, “NO” is determined in the step S03, and the process proceeds to the step 03 again. On the other hand, if an instruction is input, “YES” is determined in the step S03. The averaging time setting unit 12a instructs the test apparatus 2 to emit an optical signal to the optical line f1 using the first measurement condition (step S04). In the present embodiment, the measurement was performed under the conditions of an averaging time of 5 seconds and a pulse width of 20 ns as the first measurement conditions.
The optical signal emitted from the test apparatus 2 is branched by the splitter 3 laid in a tree shape, reflected by each terminal apparatus 4 and returned to the test apparatus 2. The test apparatus connection unit 13 acquires information on the waveform (FIG. 6) of the return light received by the test apparatus 2.

  FIG. 6 is a diagram illustrating an example of a waveform of an optical signal received by the test apparatus 2 when a failure occurs in the first embodiment of the present invention. The horizontal axis indicates the distance from the test apparatus 2, and the vertical axis indicates the reflected light intensity. The control part 12 reads the reflected light intensity corresponding to the optical line length in each termination | terminus apparatus 4a-4d in the waveform shown in FIG. Then, the optical line length and the reflected light intensity in each of the termination devices 4a to 4d are associated with each other and stored in the storage unit 14 as the reflected light intensity at the time of fault monitoring (step S05).

  Next, the attenuation amount determination unit 12 a attenuates the reflected light intensity at the time of failure monitoring of each of the terminal devices 4 a to 4 d stored in the storage unit 14 from the normal reflected light intensity stored in the storage unit 14. It is determined whether or not (step S06).

If the reflected light intensity is not attenuated, “NO” is determined in Step S06, and after waiting for a predetermined time (Step S07), the process proceeds to Step S05 again, and the process is resumed.
On the other hand, if the reflected light intensity is attenuated, “YES” is determined in step S06, and the averaging time setting unit 12a uses the second measurement condition to the optical signal from the test apparatus 2. Is sent to the optical line f1 (step S08). In the present embodiment, the measurement was performed under the conditions of an averaging time of 144 seconds and a pulse width of 20 ns as the second measurement conditions.

  The control unit 12 gives an instruction to the test apparatus 2 to emit an optical signal toward the splitter 3 using the second measurement condition. The optical signal emitted from the test apparatus 2 is branched by the splitter 3 laid in a tree shape, reflected by the terminal apparatuses 4a to 4d, and returned to the test apparatus 2. The test apparatus connection unit 13 acquires information on the waveform (FIG. 7) of the return light received by the test apparatus 2.

  FIG. 7 is a diagram illustrating an example of a waveform of an optical signal received by the test apparatus 2 when a failure occurs in the first embodiment of the present invention. The horizontal axis indicates the distance from the test apparatus 2, and the vertical axis indicates the reflected light intensity. In the measurement result (FIG. 7) measured with the averaging time set to 144 seconds, the vertical axis of the waveform is higher than the measurement result (FIG. 6) measured with the averaging time set to 5 seconds. Noise, which is a change in direction, is reduced, and the reflection abnormality p5 can be clearly identified based on the failure of the optical line.

  Returning to FIG. 4, the control unit 12 determines whether or not there is a reflection other than the reflections p1 to p4 of the termination devices 4a to 4d (step S10). If there is no reflection other than the reflections p1 to p4, it is determined as “NO” in step S10, and the terminating device (here, the terminating device 4c) determined that the reflected light intensity is attenuated in step S06 has failed. Is displayed on the display unit 15 (step S11) to notify the administrator of the optical line monitoring system according to the present embodiment.

  On the other hand, when there is a reflection other than the reflections p1 to p4, that is, when there is a reflection abnormality p5 of a predetermined reflected light intensity or more as shown in FIG. 7, “YES” is determined in step S10. Proceed to step S12. The control unit 12 obtains the fault occurrence distance from the test apparatus 2 by reading the value on the horizontal axis where the reflection abnormality p5 occurs (step S12). The control unit 12 connects an optical line f (here, f1, f2, and f5) that connects the test apparatus 2 and the termination device 4 (here, the termination device 4c) that has been determined that the reflected light intensity is attenuated in step S06. By displaying on the display unit 15 that a failure has occurred at a point (here, a point on the optical line f5) away from the test apparatus 2 by the failure occurrence distance (step S13), The administrator of the optical line monitoring system according to the present embodiment is notified.

If the optical line monitoring system according to the first embodiment of the present invention is used, measurement is performed using a short averaging time (average time 5 seconds) as the first measurement condition, and the reflected light intensity of the terminating device is In the case of attenuation, the measurement was performed using a long averaging time (averaging time 144 seconds) as the second measurement condition. As a result, the measurement time can be shortened when the first measurement condition is used, and the reflection abnormality based on the failure of the optical line can be recognized from the waveform with less noise when the second measurement condition is used. Therefore, the distance to the point where the failure occurs can be accurately calculated, and the optical line can be monitored with high accuracy.
In each of the above measurements, by measuring the intensity of the reflected return light from the terminating device, it detects not only the malfunction of the terminating device but also the presence or absence of excessive line loss from the sending end (transmission side) to the terminating device. be able to. In other words, if the line is abnormal and loss is excessive, the peak of the reflected return light is reduced accordingly.
In particular, in a splitter-branched line, if a failure occurs between the splitter and the transmission end and a loss occurs, the peak of the return light from the terminating device connected to the splitter is all reduced, and therefore the splitter and the transmission line. It can be seen that a failure has occurred between the edges. A failure occurs due to various factors such as a connection point abnormality and a line (optical fiber cable) abnormality.
As described above, the presence or absence of a line loss or the like is accurately measured under the first or second measurement condition, preferably the second measurement condition.

  Next, processing of the optical line monitoring system according to the second embodiment of the present invention will be described. Regarding the configuration of the optical line monitoring system and the configuration of the optical line monitoring device 1 according to this embodiment, the configuration of the optical line monitoring system according to the first embodiment (FIG. 1) and the configuration of the optical line monitoring device 1 (FIG. 2) and Since it is the same, the description is omitted.

  Next, processing of the optical line monitoring system according to the second embodiment of the present invention will be described. The flowchart showing the process flow of the optical line monitoring apparatus 1 according to the present embodiment is substantially the same as the flowchart (FIG. 4) showing the process flow of the optical line monitoring apparatus 1 according to the first embodiment of the present invention. The processing in step S08 in FIG. 4 is different. In the present embodiment, the waveform of the return light received by emitting an optical signal using the first condition (average time 5 seconds, pulse width 20 ns) from the test apparatus 2 in the process of step S05 is shown in FIG. Is the same.

In step S08 of this embodiment, the pulse width setting unit 12b instructs the test apparatus 2 to emit an optical signal to the optical line f1 using the second measurement condition. In the present embodiment, the measurement was performed under the conditions of an averaging time of 5 seconds and a pulse width of 100 ns as the second measurement conditions.
The control unit 12 gives an instruction to the test apparatus 2 to emit an optical signal toward the splitter 3 using the second measurement condition. The test apparatus connection unit 13 acquires information on the waveform (FIG. 8) of the return light received by the test apparatus 2.

  FIG. 8 is a diagram illustrating an example of a waveform of an optical signal received by the test apparatus 2 when a failure occurs in the second embodiment of the present invention. The horizontal axis indicates the distance from the test apparatus 2, and the vertical axis indicates the reflected light intensity. In the measurement result (FIG. 8) measured with the pulse width set to 100 ns, the fluctuation in the vertical axis direction of the waveform is larger than the measurement result (FIG. 6) measured with the pulse width set to 20 ns. Certain noise is reduced, and the reflection abnormality p5 can be clearly identified based on the failure of the optical line.

  If the optical line monitoring system according to the second embodiment of the present invention is used, measurement is performed using a narrow pulse width (pulse width 20 ns) as the first measurement condition, and the reflected light intensity of the termination device is attenuated. If so, the measurement was performed using a wide pulse width (pulse width 100 ns) as the second measurement condition. Thereby, when using the first measurement condition, it is possible to clearly distinguish the reflection abnormality of reflected light from each terminal device, and when using the second measurement condition, a failure occurs from a waveform with less noise. Since the distance to a certain point can be calculated, the optical line can be monitored with high accuracy.

  Next, processing of the optical line monitoring system according to the third embodiment of the present invention will be described. Regarding the configuration of the optical line monitoring system and the configuration of the optical line monitoring device 1 according to this embodiment, the configuration of the optical line monitoring system according to the first embodiment (FIG. 1) and the configuration of the optical line monitoring device 1 (FIG. 2) and Since it is the same, the description is omitted.

  Next, processing of the optical line monitoring system according to the third embodiment of the present invention will be described. The flowchart showing the process flow of the optical line monitoring apparatus 1 according to the present embodiment is substantially the same as the flowchart (FIG. 4) showing the process flow of the optical line monitoring apparatus 1 according to the first embodiment of the present invention. The processing in step S08 in FIG. 4 is different. In the present embodiment, the waveform of the reflected light received by emitting the optical signal using the first condition (average time 5 seconds, pulse width 20 ns) from the test apparatus 2 in the process of step S05 is as shown in FIG. Is the same.

In step S08 of the present embodiment, the averaging time setting unit 12a and the pulse width setting unit 12b instruct the test apparatus 2 to emit an optical signal to the optical line f1 using the second measurement condition. give. In the present embodiment, the measurement was performed under the conditions of an averaging time of 144 seconds and a pulse width of 100 ns as the second measurement conditions.
The control unit 12 gives an instruction to the test apparatus 2 to emit an optical signal toward the splitter 3 using the second measurement condition. The test apparatus connection unit 13 acquires information on the waveform (FIG. 9) of the return light received by the test apparatus 2.

  FIG. 9 is a diagram illustrating an example of a waveform of an optical signal received by the test apparatus 2 when a failure occurs in the third embodiment of the present invention. The horizontal axis indicates the distance from the test apparatus 2, and the vertical axis indicates the reflected light intensity. In the measurement result (FIG. 9) in which the averaging time was set to 144 seconds and the pulse width was set to 100 ns, the measurement was performed with the averaging time set to 5 seconds and the pulse width set to 20 ns. Compared with the measurement result (FIG. 6), the noise that is the fluctuation in the vertical axis direction of the waveform is further reduced, and the reflection abnormality p5 can be clearly identified based on the failure of the optical line. Yes.

If the optical line monitoring system according to the third embodiment of the present invention is used, measurement is performed using a short averaging time (average time 5 seconds) and a narrow pulse width (pulse width 20 ns) as the first measurement condition. If the reflected light intensity of the termination device is attenuated, measurement is performed using a long averaging time (average time 144 seconds) and a wide pulse width (pulse width 100 ns) as the second measurement condition. I did it. Thereby, compared with 1st and 2nd embodiment, at the time of use of a 1st measurement condition, the reflected light from each terminal device can be distinguished clearly, and measurement time can also be shortened. Also, compared to the first and second embodiments, the distance from the waveform with less noise to the point where the failure has occurred can be calculated when the second measurement condition is used. Therefore, the optical line can be monitored with extremely high accuracy.
As described above, in each embodiment, the combination of the averaging time and the length of the pulse width is arbitrary, but selection is required so that the failure can be easily detected at least under the second measurement condition.

  In the embodiment described above, the functions of the input unit 11, the control unit 12, the attenuation determination unit 12a, the averaging time saving unit 12b, the pulse width setting unit 12c, the test apparatus connection unit 13, and the storage unit 14 in FIG. Alternatively, a program for realizing a part of these functions is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read by a computer system and executed to control the optical line monitoring apparatus. May be performed. Here, the “computer system” includes an OS and hardware such as peripheral devices.

  The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Further, the “computer-readable recording medium” dynamically holds a program for a short time, like a communication line when a program is output via a network such as the Internet or a communication line such as a telephone line. In this case, it is also assumed that a server that holds a program for a certain time, such as a volatile memory inside a computer system that serves as a server or client. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

1 is a schematic configuration diagram of an optical line monitoring system according to an embodiment of the present invention. It is a block diagram which shows the structure of the optical line monitoring apparatus 1 by this embodiment. It is a figure which shows an example of the information which the memory | storage part 14 by this embodiment memorize | stores. It is a flowchart which shows the flow of a process of the optical line monitoring apparatus 1 by the 1st Embodiment of this invention. In the 1st Embodiment of this invention, it is a figure which shows an example of the waveform of the optical signal which the test apparatus 2 light-receives at the time of normal. In the 1st Embodiment of this invention, it is a figure which shows an example of the waveform of the optical signal which the test apparatus 2 light-receives at the time of failure occurrence. In the 1st Embodiment of this invention, it is a figure which shows an example of the waveform of the optical signal which the test apparatus 2 light-receives at the time of failure occurrence. In the 2nd Embodiment of this invention, it is a figure which shows an example of the waveform of the optical signal which the test apparatus 2 light-receives at the time of failure occurrence. In the 3rd Embodiment of this invention, it is a figure which shows an example of the waveform of the optical signal which the test apparatus 2 light-receives at the time of failure occurrence.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical-line monitoring apparatus, 1a ... Case, 2 ... Test apparatus, 3 ... Splitter, 4 (4a-4d) ... Termination device, 5 ... Connector, 11 ... · Input unit, 12 ··· control unit, 12a · · · attenuation determination unit, 12b · · · averaging time setting unit, 12c · · · pulse width setting unit, 13 · · · test equipment connection unit, 14 · ..Storage unit, 15 ... display unit, c1 ... cable, f (f1-f6) ... optical line

Claims (6)

An optical line monitoring device (1) for monitoring a failure of an optical line (f) branched from a test device (2) by a splitter (3) and connected to a plurality of termination devices (4),
First storage means (14) for storing reflected light intensities from the plurality of termination devices with respect to an optical signal emitted by the test apparatus in a state where no failure has occurred in the optical line;
A measurement of applying a predetermined averaging time及beauty predetermined pulse width, a first control means for measuring the reflection intensity of the optical signal emitted from the test apparatus (12),
Second storage means (14) for storing the reflected light intensity measured by the first control means and reflected light intensity from the plurality of terminal devices;
Whether there is a termination device that is attenuated compared to the reflected light intensity stored in the first storage means among the reflected light intensities of the plurality of termination devices stored in the second storage means. An attenuation determining means (12a) for determining;
When the attenuation amount determining means determines that there is a terminating device in which the reflected light intensity is attenuated, the measurement is performed by changing at least one of the predetermined averaging time and the predetermined pulse width. A second control means (12);
An optical line monitoring apparatus comprising: 2. The optical line according to claim 1, wherein the second control unit makes the averaging time longer than the predetermined averaging time, or makes the pulse width wider than the predetermined pulse width. Monitoring device. 2. The optical line according to claim 1, wherein the second control unit makes an averaging time longer than the predetermined averaging time and makes a pulse width wider than the predetermined pulse width. Monitoring device. It said first control means as compared to the waveform of the measurement result by said second control means according to the measurement result waveform, the third control means determines whether or not reflection of the abnormality is present (12) When,
If the reflection of the abnormality is determined that the third control means to be present, a fourth control means for calculating the distance to the point where the abnormality has occurred from the test device (12),
The optical line monitoring apparatus according to any one of claims 1 to 3 , further comprising: A point on the optical line connecting the test apparatus and the termination apparatus determined by the attenuation amount determination means that the reflected light intensity is attenuated, and separated from the test apparatus by the distance calculated by the fourth control means. The optical line monitoring apparatus according to any one of claims 1 to 4 , further comprising display means (15) for displaying what kind of failure has occurred. An optical line monitoring method for monitoring a failure of an optical line (f) branched from a test apparatus (2) by a splitter (3) and connected to a plurality of termination apparatuses (4),
A first step of storing reflected light intensities from the plurality of termination devices with respect to an optical signal emitted by the test device in a state where no failure has occurred in the optical line;
A measurement of applying a predetermined averaging time及beauty predetermined pulse width, and a second step for measuring the reflection intensity of the optical signal emitted from the test apparatus,
A third step of storing the reflected light intensity measured in the second step , the reflected light intensity from the plurality of termination devices;
Fourth step of determining whether there is a terminal device that is attenuated compared to the reflected light intensity stored in the first step among the reflected light intensities of the plurality of terminal devices stored in the third step. When,
When it is determined in the fourth step that there is a terminating device whose reflected light intensity is attenuated, the measurement is performed by changing at least one of the predetermined averaging time and the predetermined pulse width . 5 steps,
An optical line monitoring method characterized by comprising:

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