JP4044085B2 - Optical line, optical communication line monitoring system, optical communication line monitoring method - Google Patents

Description

  The present invention relates to line monitoring of an optical communication line.

  Currently, for the purpose of line monitoring of optical communication lines, optical communication lines combining optical pulse testing machines (hereinafter referred to as OTDR), PCs (personal computers or those having equivalent functions), optical switches, etc. A surveillance system is in use. 7 and 8 show an example of an optical communication line monitoring system. An optical communication line monitoring system 111 in FIG. 7 is an optical communication line monitoring system that monitors a representative core line (monitoring line) 102 of the optical communication line 101. An optical communication line monitoring system 112 in FIG. This is an optical communication line monitoring system for monitoring the current core 103. In any system, a line distance-light intensity diagram based on the test result of the optical communication line in the initial state (normal state) measured by the OTDR 104 is stored (stored) in the PC 105, and is tested periodically or when a failure occurs. By comparing the line distance-light intensity diagram based on the test results and the line distance-light intensity diagram based on the initial test results, the presence / absence of failure and the occurrence status (position, type, etc.) should be detected. Is possible. By using the optical switch 106, for example, a system that monitors the optical communication line 101 having a plurality of cores such as an optical cable can be provided.

  FIG. 9 schematically shows a line distance-light intensity diagram based on a test result by OTDR 104 of an optical communication line. The lower right overall indicates the loss of the optical fiber itself of the optical communication line under test such as the representative core wire 102 and the active core wire 103. As the distance from the OTDR 104 becomes longer, the Rayleigh It shows that the reflected light due to scattering becomes weak. The steps 113 and 114 seen in the middle of the optical communication line are connection losses, the step 113 having no peak is fusion spliced, and the step 114 having a peak is connector connected. In the case of a connector end face or the like, the end of the optical communication line has a Fresnel reflection peak 115 as shown in FIG. In this way, the line distance-light intensity diagram is derived from the test result of each optical communication line by the OTDR 104, and stored (stored) in the PC 105 as an initial state. The position of each connection point and the connection loss are automatically detected and stored as event data. Then, thereafter, the optical communication line is periodically tested, and this initial state is compared as a reference. If there is no change in the line distance-light intensity diagram, it is determined that there is no abnormality in the optical communication line. Alternatively, when a failure occurs in communication, the optical communication line is tested, and the line distance-light intensity diagram is compared with the initial state to grasp the failure state of the optical communication line. FIG. 10 is a line distance-light intensity diagram based on the result of the OTDR test when a failure occurs. In the figure, the initial state is indicated by a broken line as a reference. It can be seen that there is a step 117 that was not seen in the initial state at the failure occurrence location 116 in FIG. A decrease in light intensity such as the step 117 represents a loss. From this result, it is possible to identify the location and type of failure (in this example, there is no peak, so there is no reflection, so there is a high possibility of loss due to bending), and smooth failure recovery can be performed. It becomes. Many actual track monitoring systems have a function of automatically detecting and discriminating the location and type of failure by a calculation function in the PC and transmitting an alarm. In FIG. 10, the diagram after the failure (solid line) and the diagram in the initial state are actually completely coincident with the two diagrams before the failure location 116. I drew it a little on purpose.

  In this way, the optical line monitoring system is fixedly used with respect to the optical communication line, and it is common to measure the optical communication line as necessary and check the failure occurrence state of the optical communication line. Since OTDRs, optical switches, and the like that are very expensive are expensive to install an optical communication line monitoring system for all optical communication lines. For this reason, a portable optical communication line monitoring system has been developed in which a line monitoring system is attached and used only when necessary, such as when a failure occurs.

Moreover, in such an optical communication line monitoring system, Patent Document 1 discloses a technique for suppressing variation in results for each test. According to Patent Document 1, when obtaining the value of the return loss of the specific section delimited by the marker, first, the known light return loss of the calibration optical fiber is set in the light return loss input circuit, Connect the calibration optical fiber to the OTDR, measure the light return loss, divide the known light return loss set in the light return attenuation input circuit by the arithmetic circuit by the measured value, and obtain the light reception gain correction value. Connect the optical fiber to be measured to the OTDR, set an arbitrary section with the marker point input circuit, and the arithmetic circuit integrates the measured waveform data of the set section with the distance to obtain the optical return loss, and calculates the received light gain correction value. Multiply and display the optical return loss of the optical fiber under measurement in the section set by the marker point input circuit.
JP-A-8-271753

However, in the case of a portable optical communication line monitoring system, the following points are problematic.
(1) Because an optical communication line monitoring system is constructed and connected to the line for each test, the difference between the connection losses (non-reproducibility of connection loss) causes the initial and subsequent test results to be Even if there are no obstacles on the track, they do not match.
(2) If a device (OTDR) different from that in which the initial state was tested is used, the test results do not match due to machine differences between devices. (Since OTDR is expensive, it is often handled by rental from a rental company. In this case, there is no guarantee that the same OTDR can be rented every time, and it is necessary to be able to deal with different OTDRs.)
FIG. 11 shows the state (1). A broken line shows a line distance-light intensity diagram in an initial state, and a solid line shows a line distance-light intensity diagram in a state where the device is once disconnected and attached again. As shown in the figure, the loss at the connector connecting portion after reconnection increases, and the diagrams do not match. For this reason, there arises a problem that the initial line distance-light intensity diagram cannot be used as a reference.
FIG. 12 shows the state (2). A broken line shows an initial line distance-light intensity diagram, and a solid line shows a line distance-light intensity diagram when using an OTDR different from the OTDR in which the initial state was tested. As shown in the figure, the inclination of the entire diagram is different from the x-coordinates of the steps 113a and 113b. This means that the loss of the optical communication line itself, which should be the same in reality, is displayed differently from the loss occurrence position of the fusion splice, for example, and the initial line distance-light intensity diagram The problem that cannot be used as a reference occurs. That is, if there is a deviation in the line distance-light intensity diagram between the initial test and the subsequent test, it is difficult to determine whether or not the optical line is faulty. When automatic discrimination is performed on software normally used in a monitoring system, misidentification of a failure occurs and becomes a problem.
In FIG. 11 and FIG. 12, the difference in the diagram is exaggerated from the actual test result in order to make the difference in the diagram easier to understand.

It is also conceivable to apply a technique as disclosed in Patent Document 1 to these problems. However, the technique disclosed in Patent Document 1 has the following problems and cannot solve the above problems. That is,
(A) The method disclosed in Patent Document 1 corrects only the value of the return loss, and does not correct the line distance-light intensity diagram. It cannot cope with variations in position and lacks visibility. In addition, the configuration of the optical fiber for calibration suitable for correcting the line distance-light intensity diagram is not shown at all.
(B) According to Patent Document 1, the calibration optical fiber is “measured in advance with a CW light source and a power meter”, but the gain correction value determined by the calibration optical fiber not including any particular loss is It is very small and is insufficient as a correction for optical communication line monitoring including a larger variation factor such as a loss of a connection location.
(C) In the method according to Patent Document 1, the connection loss and the return loss of the connection portion may change every time the calibration fiber is connected, but such variations such as the connection loss are not dealt with at all. .

  In order to solve these problems, the present invention corrects a change in the line distance-light intensity diagram due to machine differences even if the OTDR used changes, and can monitor only an actual state change. It is an object to provide an optical line suitable for a system, an optical communication line measuring method, or correction. More preferably, an object of the present invention is to provide an optical communication line monitoring system that does not affect the test result of variations in connection loss for each OTDR connection.

In order to achieve the above object, the present invention provides means for solving the problems with the following configuration and method. That is,
The optical line according to claim 1 is an optical line inserted between the optical pulse tester and the optical communication line to be tested, and has two or more loss parts in the optical line.
An optical line according to a second aspect is the optical line according to the first aspect, wherein the two or more loss portions have different loss values.
An optical line according to claim 3 is the optical line according to claim 1 or 2, wherein the optical line is connected to the optical pulse testing machine and / or the optical communication line to be tested by an optical connector. .

An optical communication line monitoring system according to a fourth aspect includes the optical line according to any one of the first to third aspects, an optical pulse tester, and an optical communication line to be tested. A storage means inserted between a pulse tester and the optical communication line under test, and storing a past optical pulse test result of the optical line; a current optical pulse test result of the optical line; and a past of the optical line It further has a correcting means for correcting the test result of the optical communication line under test based on the optical pulse test result.
The optical communication line monitoring system according to claim 5 is the optical communication line monitoring system according to claim 4, wherein the optical line includes the optical pulse tester and / or the optical communication line to be tested and an optical connector. And an optical connector correction unit that regards a loss at a location connected by the optical connector as a loss similar to a line portion without a connection location.
According to a sixth aspect of the present invention, there is provided an optical communication line monitoring method comprising: inserting an optical line between an optical pulse tester and an optical communication line to be tested; 1 line diagram is compared with the second line diagram of line distance-light intensity based on the current optical pulse test of the optical line, and the correction calculation that makes the first and second diagrams the same is determined, Based on the optical pulse test result of the test optical communication line, the correction calculation is performed on the line distance-light intensity third diagram to derive the line distance-light intensity fourth diagram, and the optical pulse test result of the past optical communication line to be tested is obtained. The line distance-light intensity based on the fifth diagram and the fourth diagram are compared.
The optical communication line monitoring method according to claim 7 is the optical communication line monitoring method according to claim 6, wherein the optical line has two or more loss parts in the optical line. .
The optical line monitoring method according to claim 8 is the optical communication line monitoring method according to claim 6 or 7, wherein the optical line includes the optical pulse tester and / or the optical communication line to be tested and a light. Optical connector portion correction is further performed in which the loss at the portion connected by the connector is regarded as the loss similar to the line portion having no connection portion.

According to the optical line of claim 1, the correction calculation of the line distance-light intensity diagram based on the OTDR test result of the optical communication line is determined based on the OTDR test result of the optical line. Since there is a distance between the loss part with little fluctuation and the loss part with little fluctuation, when determining the correction calculation, it is easy and highly accurate by using the loss value in the line and the distance between the loss parts as a reference. A correction calculation can be determined. That is, even if there is a difference in the OTDR, if there is no failure in the optical communication line (when there is no change from the initial state), the line distance-light intensity diagram based on the test result by this OTDR is the same as the initial state. In addition, when there is a failure, the waveform after the failure point is drawn so that the waveform is different, so that it is possible to accurately grasp the location and degree of the failure. In other words, when OTDR and the optical line are configured separately, even when OTDR is arranged for each test, the same characteristics as when OTDR is fixed and used can be realized, and any OTDR (manufacturer, model) can be used. It is suitable for construction of an optical communication monitoring system that can be performed. In other words, it is possible to use an expensive OTDR also for another optical communication line test, or to use a rental one, and to provide an optical line monitoring system that is very economical. It becomes possible.
In addition, according to the optical line of claim 2, by making the loss values of the loss portions provided in the optical line different from each other, the line distance-light intensity diagram without deviation can be corrected more accurately. Is possible.
Further, according to the optical line of claim 3, the optical line and the OTDR and / or the optical line and the optical communication line to be tested are connected to each other by an optical connector, thereby Easy to construct and dismantle. Moreover, it becomes possible to construct again, and it becomes possible to set it as the optical communication line monitoring system excellent in portability.

According to the optical communication line monitoring system of the fourth aspect, it is possible to realize appropriate optical communication line monitoring by correcting the variation of the line distance-light intensity diagram due to the difference in OTDR.
According to the optical communication monitoring system of claim 5, since the optical line is connected to the optical pulse tester and / or the optical communication line under test by an optical connector, the system can be constructed, disassembled, and reconstructed. It becomes easy. In addition, since it further has an optical connector correction means that regards the loss at the location connected by the optical connector as the same loss as the line portion without the connection location, even if the loss at the connector connection varies every time the optical connector is connected, Appropriate optical communication monitoring is possible by eliminating the influence on the line distance-light intensity diagram of the communication line.
According to the optical communication line monitoring method of claim 6, proper optical communication monitoring is performed by correcting the line distance-light intensity diagram based on the optical line inserted between the OTDR and the optical communication line under test. Is possible.
According to the optical communication line monitoring method of claim 7, the correction calculation of the line distance-light intensity diagram based on the OTDR test result of the optical communication line is determined based on the OTDR test result of the optical line, Since there is a distance between the loss part with little fluctuation and the loss part with little fluctuation in the line, when determining the correction calculation, it is easy and easy by using the loss value and the distance between the loss parts in the line as a reference. It can be performed with high accuracy.
According to the optical communication line monitoring method of claim 8, since the optical line is connected to the optical pulse tester and / or the optical communication line under test by an optical connector, the system is constructed, disassembled, and reconstructed. Becomes easy. In addition, since it further has an optical connector correction means that regards the loss at the location connected by the optical connector as the same loss as the line portion without the connection location, even if the loss at the connector connection varies every time the optical connector is connected, Appropriate optical communication monitoring is possible by eliminating the influence on the line distance-light intensity diagram of the communication line.

  Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing a first embodiment of an optical communication line monitoring system according to the present invention. In the optical communication line monitoring system 11 shown in the figure, an optical line part 7 for correction is connected between the OTDR 4 and the representative core wire 2 to be tested in the optical cable (optical communication line 1) with connector connecting parts 8, 8 '. It is installed with the connector connected. The OTDR 4 is connected via a communication cable 10 (broken line) to a PC 5 for controlling the test and recording and calculating the test result. The optical line section 7 accommodates an optical fiber having a length of about 1 km, and has a correction loss 9 of 0.9 dB and a correction loss 9 ′ of 0.6 dB at positions 300 m and 600 m from the OTDR 4 side, respectively. Is provided. The correction losses 9 and 9 'are formed by misalignment fusion in which the cores are artificially misaligned during fusion splicing of the optical fibers to effect fusion splicing. Axial misalignment enables the creation of an arbitrary loss accurately and easily by adjusting the amount of misalignment, and there is no loss fluctuation due to the external environment (temperature, humidity, etc.), and it is extremely stable. It has special characteristics. In the enlarged view of FIG. 1, the optical fiber constituting the optical line portion 7 is actually housed in a coiled form, but in FIG. 1, the internal structure (compensation loss 9, 9 ′).

Note that the optical communication line monitoring system 11 in FIG. 1 shows an example of an optical communication line monitoring system for monitoring the representative core wire 2. In addition, the optical communication line 1 shown in the figure does not include the connection point of the optical line, the actual wiring state, etc., and actually has, for example, five fusion splices within a length of about 3 km, One connector connection is provided.

FIG. 2 shows a line distance-light intensity diagram based on a test result by OTDR4 of the optical communication line monitoring system 11 shown in FIG. In the line distance-light intensity diagram shown in the figure, a diagram 20 of the optical path portion 7 for correction is shown before the diagram 21 of the representative core wire 2 to be tested. In the diagram, the two steps 22 and 22 'in the corresponding portion 20 of the correction optical line portion 7 correspond to the losses of the correction losses 9 and 9' of 0.9 dB and 0.6 dB, respectively. . Further, on the diagram, a step 23 and a reflection peak 24 at the connection point due to the connection loss between the optical line portion 7 and the connector connection portion 8 ′ of the representative core wire 2 are seen.

Next, a method for monitoring an optical communication line when this line distance-light intensity diagram is in an initial state (reference) will be described. The line distance-light intensity diagram in FIG. 2 is stored (stored) in the PC 5 together with individual information of the optical communication line (cable name, installed location, etc.). The optical communication line monitoring system of the present invention is portable, and is normally in a state of being detached from the representative core wire 2 at the connector connection portion 8 '. Then, the apparatus is connected again to measure the line regularly (for example, every other month) or when there is an abnormality in communication. The OTDR used at this time may be a different model from that used in the initial measurement.
FIG. 3 shows a line distance-light intensity diagram based on a test result using an OTDR that is different from the initial line distance-light intensity diagram (broken line, hereinafter referred to as an initial diagram for convenience) and an initial state test. A solid line, hereinafter referred to as a current diagram for convenience). In the initial diagram, steps 22a and 22'a corresponding to the correction losses 9 and 9 'in the corresponding portion 20a of the correction optical line portion 7, steps 23a and peaks 24a corresponding to the losses in the connector connecting portion 8', and representative In the diagram 21a of the core wire 2, the step 14a due to the loss of the connector connecting portion, the step 13a due to the loss of the fusion splicing portion, and the Fresnel reflection peak 15a on the connector end face can be observed. Similarly, in the current diagram, the steps 22b and 22'b corresponding to the correction losses 9 and 9 'in the diagram 20b of the optical line portion 7 for correction, the step 23b corresponding to the loss of the connector connecting portion 8', and the peak 24b. In the diagram 21b of the optical communication line portion 1, a step 14b due to the loss of the connector connecting portion, a step 13b due to the loss of the fusion splicing portion, and a Fresnel reflection peak 15b on the connector end face can be observed. The initial diagram and the current diagram differ in the slope of the entire diagram, the position of the step corresponding to each loss, the height of the step indicating the loss value, etc., and it can be seen that the diagram is misaligned (note that In the same figure, the deviation of the waveform is shown larger than the actual one so that the difference between the waveforms can be easily understood). As described above, if there is a difference between the initial diagram and the current diagram, it is difficult to determine whether or not a failure has occurred in the representative core wire 2. In particular, fault recognition of a fault occurs during automatic discrimination on software, which is usually used in an optical communication line monitoring system.

  FIG. 4 shows a state in which the line distance-light intensity diagram is corrected by the optical communication line monitoring system 11 of the present invention. That is, a state is shown in which correction is performed so that the corresponding portions 20a and 20b of the optical line portion 7 for correction on the line distance-light intensity diagram match. In addition, the steps 23a and 23b and the peaks 24a and 24b corresponding to the loss of the connector connecting portion 8 'are also corrected. This state is a case where there is no change in the representative core wire 2 at the time of the initial test and the current test, but on the diagram, by matching the corresponding portions 20a and 20b of the optical line portion 7, on the diagram, Corresponding portions 21a and 21b of the representative core wire 2 being the test object also coincide with each other and correctly indicate the actual situation.

A specific correction procedure will be described below. In FIGS. 13 to 18, the initial diagram is indicated by a broken line and the current diagram is indicated by a solid line. Corresponding to the correction loss 9 in the correction optical line, loss start points 22a1 and 22b1 and loss end points 22a2 and 22b2 appear in the diagram. Similarly, loss start points 22'a1, 22'b1, loss end points 22'a2, 22'b2 corresponding to the correction loss 9 ', loss start points 23a1, 23b1, loss end point corresponding to the loss of the connector connecting portion 8'. 23a2, 23b2 and peaks 24a, 24b appear. FIG. 13 is a diagram before correction, and each point has a difference between the initial diagram and the present diagram due to the difference in OTDR and the variation in loss when the connector is connected. First, an addition / subtraction operation is performed on the entire current diagram from this state to match the loss start points 22a1 and 22b1. This state is shown in FIG.

Second, the loss value of the correction loss 9 for correcting the diagram corresponding to the correction loss 9 is the difference between the y coordinates of 22a1 and 22a2 (initial diagram) or 22b1 and 22b2 (current diagram) on the diagram. Appears as When the loss value of the initial diagram is x and the loss value of the current diagram is y, y is multiplied by a certain correction coefficient a1 so that x = y. That is, for example, when x = 0.9 (dB) and y = 1.0 (dB), a1 = 0.9. In addition, more accurate loss correction is possible by setting two correction losses and different values. That is, when another correction loss 9 ′ is displayed as 0.6 (dB) in the initial diagram and 0.62 (dB) in the current diagram, the correction coefficient a2 = 0. 97. Here, if an average value of 0.935 of a1 and a2 is adopted as a correction coefficient for the loss value, a more preferable correction without deviation is possible. With this correction, as shown in FIG. 15, the loss start points 22a1 and 22b1 and 22a2 and 22b2 coincide. In addition, the diagrams corresponding to the respective loss values such as the y-coordinate differences between 22′a1 and 22′a2 and 22′b1 and 22′b2 are corrected.

Third, a method for correcting the inclination of the diagram will be described. Since the Rayleigh scattering coefficient of the same general optical fiber is substantially constant with respect to the longitudinal direction, the line distance-light intensity diagram based on the OTDR test is substantially straight except for the connecting portion. Therefore, this diagram can be approximated by a linear expression. What is necessary is just to obtain | require the inclination (primary coefficient) of this linear equation (specifically, it obtain | requires by the least squares method from the data point of a diagram). Then, the coefficient b in the slope of the current diagram is multiplied so that the slope of the initial diagram is the same as the slope of the current diagram. When two correction losses 9 and 9 'are provided in the correction optical line section 7 as in the present embodiment, the correction coefficient for the diagram corresponding to the two correction losses 9 and 9' is provided. By determining b, correction can be performed easily and with high accuracy. Specifically, as shown in FIG. 16, the line segment 22a2-22′a1 in the initial diagram may be corrected to overlap the line segment 22b2-22′b1 in the current diagram. Even when the correction optical lines 7 are not provided with the correction losses 9 and 9 ', the inclination can be corrected and a certain effect can be enjoyed.

Fourth, a distance correction method will be described. The distance between the correction losses 9-9 ′ in the correction optical line 7 is expressed as an x-coordinate difference on the diagram. That is, the x-coordinate difference between 22a2 and 22'a1 on the initial diagram is p, the x-coordinate difference between 22b2 and 22'b1 on the current diagram is q, and the correction coefficient c in the current diagram so that Multiply With this correction, the diagram becomes the state shown in FIG.

Fifth, correction of the diagram corresponding to the loss of the connector connecting portion 8 'will be described. Even if the first to fourth corrections are performed, the loss of the connector connecting portion 8 'varies in each connection, so the initial diagram and the current diagram do not match. Further, since the loss of the connector connecting portion 8 'is not a monitoring target, the result is not necessary. Therefore, it is sufficient to perform correction so as to ignore the loss of the connector connecting portion 8 '. That is, as shown in FIG. 18, in the initial diagram, the addition and subtraction operations are performed on the entire diagram after the loss end point 23a2, and the loss start point 23a1 and the loss end point 23a2 are matched. Similarly, the loss start point 23b1 and the loss end point 23b2 are matched in the current diagram.

Although not shown, the same correction is performed for the loss of the connector connecting portion 8 of the OTDR 4 and the optical line portion 7 for correction. Also in these drawings, in order to make it easy to understand that two waveforms exist, the waveforms of the initial measurement and the actual measurement are drawn with a slight shift, and the diagrams are actually almost identical. In the present embodiment, the first to fifth corrections are performed, but the same effect can be obtained even if the correction order is changed. Further, even when all the first to fifth corrections are not performed and only a specific correction is performed, a certain effect can be enjoyed.

FIG. 5 shows a waveform when a failure occurs. At the failure occurrence location 25, a step 26 is generated in the diagram, and it can be seen that a loss that has not been seen in the initial diagram has occurred. In this way, if the diagram is corrected, it is possible to accurately grasp the change in the state of the optical communication line, and it is possible to avoid problems such as faulty recognition during automatic determination. . In this example, for the sake of intuitive understanding by visual observation, each line diagram is drawn on the screen in an overlapping manner, and the fault is detected by the shift of the line diagram. Can be analyzed even in a state in which is broken down into a loss part and a straight line part.
As described above, when the optical line monitoring system of the present invention is used, an accurate optical line with the initial diagram as a reference can be used even if the apparatus is separated and reconnected or an OTDR different from the initial measurement is used. Monitoring can be realized.
In this embodiment, the line length of the correction optical line section, the number of correction losses, the loss value, and the position are examples, and can be appropriately set according to the laying situation of the optical communication line to be tested. It is. Also, perform an initial test on a plurality of different optical lines for correction, and when performing an actual test, compare using the initial diagram when using the optical line for correction used in the test. Thus, it is possible to use a plurality of correction optical line portions.
Moreover, the correction loss does not have to be misaligned fusion, and a stable loss portion with respect to the external environment can be realized by, for example, producing a minute defect in the optical fiber or a mode field expansion portion. .
Further, in this embodiment, the diagram of the optical line section for correction is also shown on the same screen, but in the actual optical line monitoring system, the diagram of the optical path section for correction is displayed. It is not necessary. Alternatively, the line color of the diagram may be changed, or the background color of the graph may be changed so that the distinction from the correction optical line portion is easy to understand.
In addition, test data such as initial diagram data may be stored in a data server or the like placed on the network, so that the PC used for the test can be fixed or the data can be moved each time. There is no need to do so, and operation can be made convenient.
Further, the storage function and calculation function of the PC can be provided in the OTDR, and in this case, the PC is not necessary. However, in this case, it is necessary to use an OTDR having a storage function and a calculation function every time, and it is necessary to move initial test data.
The optical line monitoring system of the present invention can also be applied to a monitoring system for monitoring an active optical communication line. That is, as shown in FIG. 6, the connection is performed in such a manner that a correction optical line portion 7 is disposed between the OTDR 4 and the optical switch 6. The optical switch 6 and the OTDR 4 are controlled by the PC 5, and an OTDR test is performed for each optical fiber. The optical switch 6 may be installed on the optical communication line 1 or may be portable. When making it portable, it is preferable to correct the connection loss between the optical switch 6 and the optical communication line 1 as well.
As shown in the above embodiments, according to the present invention, even if an optical communication line monitoring system is constructed and connected to the line every time it is tested, the initial difference is caused by the difference in connection loss (non-reproducibility of connection loss). The test result and the subsequent test result are not deviated from each other. This change can be detected only when a change occurs in the state of the optical communication line, and accurate line maintenance can be performed. Therefore, even if the optical communication line monitoring system is portable, it is possible to have functions and performance equivalent to those of the installation type. Further, according to the present invention, even if a different model of OTDR is used for each test, the diagram can be accurately compared with the initial test by performing the diagram correction in the optical line section for correction. It is possible to realize a possible optical communication line monitoring system.

1 is a schematic diagram of an optical line monitoring system according to Embodiment 1 of the present invention. The line distance-light intensity | strength diagram (initial diagram) by the optical line monitoring system which concerns on Embodiment 1 of this invention. The line distance-light intensity diagram (before correction | amendment) by the optical line monitoring system based on Embodiment 1 of this invention. The line distance-light intensity | strength diagram by the optical line monitoring system which concerns on Embodiment 1 of this invention (after correction | amendment). Line distance-light intensity diagram by the optical line monitoring system according to the first embodiment of the present invention (after correction and after failure) Schematic of the optical line monitoring system which concerns on Embodiment 2 of this invention. Schematic of the conventional optical line monitoring system (representative core wire monitoring). Schematic of a conventional optical line monitoring system (active core monitoring). The line distance-light intensity diagram by the conventional optical line monitoring system. The line distance-light intensity diagram by the conventional optical line monitoring system. Line distance vs. light intensity diagram by conventional optical line monitoring system Line distance vs. light intensity diagram by conventional optical line monitoring system The line distance-light intensity diagram (before correction | amendment) by the optical line monitoring system based on Embodiment 1 of this invention. The line distance-light intensity diagram (after 1st correction | amendment) by the optical line monitoring system based on Embodiment 1 of this invention. The line distance-light intensity | strength diagram by the optical line monitoring system based on Embodiment 1 of this invention (after 2nd correction | amendment). The line distance-light intensity | strength diagram by the optical line monitoring system based on Embodiment 1 of this invention (after 3rd correction | amendment). The line distance-light intensity | strength diagram by the optical line monitoring system based on Embodiment 1 of this invention (after 4th correction | amendment). The line distance-light intensity | strength diagram by the optical line monitoring system based on Embodiment 1 of this invention (after 5th correction | amendment).

Explanation of symbols

1 Optical communication line 2 Representative core 3 Active core 4 OTDR
5 PC
6 Optical switch 7 Optical line part 8, 8 'Connector connection part 9, 9' Correction loss 10 Communication cable 11 Optical communication line monitoring system 12 Optical communication line monitoring system 13 Step (corresponding to fusion connection loss)
13a Step (Initial diagram, corresponding to fusion splice loss)
13b Step (This diagram, corresponding to fusion splice loss)
14 steps (corresponding to connector connection loss)
14a Step (Initial diagram, corresponding to connector loss)
14b Step (This diagram, corresponding to connector connection loss)
15 Peak (corresponding to connector end face)
15a peak (corresponds to initial diagram, connector end face)
15b Peak (corresponding to the current diagram and connector end face)
20 Correction optical line part corresponding part 20a Correction optical line part corresponding part (initial diagram)
20b Corresponding part of optical line for correction (current line diagram)
21 Representative core wire corresponding portion 21a Representative core wire corresponding portion (initial diagram)
21b Representative core wire corresponding part (current line diagram 22 step (corresponding to correction loss))
22a Step (corresponding to loss for correction, initial diagram)
22b Step (corresponds to loss for correction, current diagram)
22a1 Loss start point (initial diagram)
22a2 Loss end point (initial diagram)
22b1 Loss start point (current line diagram)
22b2 Loss end point (current line diagram)
22 'step (corresponding to correction loss)
22'a step (corresponding to correction loss, initial diagram)
22'b Step (corresponding to loss for correction, current diagram)
22'a1 Loss start point (initial diagram)
22'a2 Loss end point (initial diagram)
22'b1 Loss start point (current line diagram)
22'b2 Loss end point (current line diagram)
23 steps (corresponding to loss of connector connection)
23a Level difference (corresponding to connector connection loss, initial diagram)
23b Level difference (corresponding to connector connection loss, current diagram)
23a1 Loss start point (initial diagram)
23a2 Loss end point (initial diagram)
23b1 Loss start point (current line diagram)
23b2 Loss end point (current line diagram)
24 peak (corresponds to reflection at connector connection)
24a peak (corresponds to reflection at connector connection, initial diagram)
24b Peak (corresponds to reflection at the connector connection, current diagram)
25 Failure occurrence place 26 Step (corresponding to failure)
101 optical communication line 102 representative core wire 103 active core wire 104 OTDR
105 PC
106 Optical switch 111 Optical communication line monitoring system 112 Optical communication line monitoring system 113 Step (corresponding to fusion splicing loss)
113a Step (corresponding to fusion splice loss)
113b Step (corresponding to fusion splice loss)
114 steps (corresponding to connector connection loss)
115 peak (corresponding to connector end face)
116 Fault location 117 Step (corresponding to fault)

Claims (8)

An optical line inserted between an optical pulse tester and an optical communication line to be tested, wherein the optical line has two or more loss parts in the optical line.   2. The optical line according to claim 1, wherein the two or more loss parts have different loss values.   3. The optical line according to claim 1, wherein the optical line is connected to the optical pulse tester and / or the optical communication line to be tested by an optical connector.   4. The optical line according to claim 1, wherein the optical line is inserted between the optical pulse tester, the optical communication line under test, the optical pulse tester and the optical communication line under test, and the optical line. Storage means for storing the past optical pulse test results, and correcting the test results of the optical communication line under test based on the current optical pulse test results of the optical line and the past optical pulse test results of the optical line. An optical communication line monitoring system, further comprising a correction unit.   5. The optical communication line monitoring system according to claim 4, wherein the optical line is connected to the optical pulse testing machine and / or the optical communication line to be tested by an optical connector, and is connected to the portion connected by the optical connector. An optical communication line monitoring system, further comprising an optical connector correction unit that regards the loss as a loss similar to a line portion having no connection portion.   An optical line is inserted between the optical pulse testing machine and the optical communication line to be tested, and a line distance-light intensity first diagram based on the past optical pulse test results of the optical line, and the optical pulse of the current optical line The line distance based on the test is compared with the second line diagram of the light intensity, the correction calculation for determining the same first and second lines is determined, and the line distance based on the optical pulse test result of the current optical communication line to be tested -The above-mentioned correction calculation is performed on the light intensity third diagram to derive the line distance-light intensity fourth diagram, and the line distance-light intensity fifth diagram based on the optical pulse test result of the past optical communication line to be tested- A method for monitoring an optical communication line, which is compared with a fourth diagram.   The optical communication line monitoring method according to claim 6, wherein the optical line has two or more loss parts in the optical line. The optical communication line monitoring method according to claim 6 or 7, wherein the optical line is connected to the optical pulse tester and / or the optical communication line to be tested by an optical connector and connected by the optical connector. An optical communication line monitoring method characterized by further performing optical connector correction, which regards a loss at a part as a loss similar to a line part without a connection part.

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