JP2005147997A - Measuring method using otdr-measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring method with an OTDR-measuring instrument for measurement, using the OTDR with higher precision. <P>SOLUTION: Prescribed measuring items for a reference fiber are measured with a plurality of OTDR-measuring instruments. If a measured value is decided as being abnormal, after deciding presence of abnormality in the measured value, the light source of an OTDR-measuring instrument which has been decided as being abnormal is replaced with a new light source, and measurement is carried out for the reference fiber again to decide abnormality. So, if it is decided that there is no abnormality, the prescribed items are measured, as they are. Thus, deciding to be abnormal with an optical fiber, when an abnormality occurs with a measured value because of abnormality of a light source or the like is prevented, for measurement with higher accuracy. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a measurement method using an OTDR measuring instrument.

Conventionally, manufactured products such as optical fibers are generally inspected using a measuring instrument, and certain products are generally excluded. Therefore, when there is an abnormality in the measuring device to be inspected and a proper inspection is not performed, a certain product may be overlooked and distributed, or a normal product may be discarded as an abnormality.
Therefore, monitoring of abnormality of the measuring instrument itself for performing the inspection is performed (for example, refer to Patent Document 1 and Patent Document 2).

  By the way, OTDR (Optical Time Domain Reflectometer) is widely used in the manufacturing and inspection processes of optical fibers. This OTDR is a device that measures the breaking point or loss of an optical fiber by inputting a light pulse from one end of the optical fiber and analyzing scattered light and reflected light generated in the optical fiber. When OTDR is used in this way, measurements such as single-wavelength loss and abnormal point detection of an optical fiber can be performed at a time, so that it is widely used.

JP-A-6-347300 (page 3, FIG. 1) Japanese Patent Laid-Open No. 8-16209 (pages 5 and 6 and FIG. 1)

In addition, with the development of Raman amplification technology, C-WDM (Coarse Density Wavelength Division Multiplexing) has emerged, not only the 1.3 μm band and 1.55 μm band (C-band) so far, but also the 1.4 μm band. (S-band) and 1.6 μm band (L-band) have also been used.
Therefore, there is a demand for guaranteeing in these wavelength bands by OTDR, but there is an unknown part in the durability of the laser or the stability of the laser and sensor when used as OTDR for these wavelength bands. Therefore, there is a demand for management of measured values for measuring these OTDRs in the new wavelength band with high accuracy, and prompt determination and detection of abnormalities when there is an abnormality in the apparatus.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a measurement method using an OTDR measuring device that can improve the accuracy of measurement using OTDR.

  In order to achieve the above-described object, a measurement method using an OTDR measuring device according to the present invention measures a predetermined measurement item for a reference fiber using a plurality of OTDR measuring devices, and whether there is an abnormality in the measurement value of the predetermined measurement item. When an abnormality is determined for one of the OTDR measuring devices, the light source of the OTDR measuring device for which the abnormality is determined is replaced with a new light source, and measurement is performed again with the reference fiber. Whether or not there is an abnormality is determined, and when the abnormality is not determined, the predetermined measurement item is measured.

  In the measurement method using the OTDR measuring device configured as described above, a predetermined measurement item is measured for the reference fiber using a plurality of OTDR measuring devices. Then, it is determined whether there is an abnormality in the measured value. If the measured value is determined to be abnormal, the light source of the OTDR measuring device determined to be abnormal is replaced with a new light source, and the reference is again performed. Measure the fiber to determine the anomaly. As a result, when it is not determined to be abnormal, the measurement of the predetermined item is performed as it is, so that it is possible to prevent the determination of the optical fiber abnormality when there is an abnormality in the measured value due to an abnormality in the light source or the like, High accuracy of measurement can be achieved.

  In the measurement method using the OTDR measuring device according to the present invention, the predetermined measurement item for the reference fiber is measured by a plurality of OTDR measuring devices, the presence or absence of an abnormality in the measurement value of the predetermined measurement item is determined, and the OTDR measurement is performed. When an abnormality is determined for one of the instruments, the measurement is performed by the OTDR measuring instrument in which it is determined that there is no abnormality.

  In the measurement method using the OTDR measuring device configured as described above, a predetermined measurement item is measured for the reference fiber using a plurality of OTDR measuring devices. Then, when it is determined whether or not the measurement value is abnormal, and it is determined that the measurement value is abnormal, the OTDR measurement device that is determined to have no abnormality is substituted for the OTDR measurement device that is determined to be abnormal. Use to measure. For this reason, it is possible to prevent the use of an OTDR measuring device that may be abnormal and to improve the measurement accuracy.

  Further, in the measurement method using the OTDR measuring device according to the present invention, it is desirable to determine that the OTDR measuring device is abnormal when the measured value is out of a predetermined reference numerical value range.

  In addition, the measuring method using the OTDR measuring device according to the present invention is such that, in each of the OTDR measuring devices, when a change with time in the data of the measured value for a predetermined period is out of the predetermined range, the measurement is out of the predetermined range. It is desirable to determine that there is an abnormality in the OTDR measuring instrument.

  In addition, the measuring method using the OTDR measuring device according to the present invention calculates the standard deviation of the data of the measurement value for a predetermined period, and determines that there is an abnormality when the standard deviation deviates from the predetermined reference deviation. It is desirable.

  Further, the measuring method by the OTDR measuring device according to the present invention calculates an approximate straight line of the data of the measured value for a predetermined period, and when the slope and the intercept deviate from the predetermined reference slope and the reference intercept, respectively, It is desirable to judge that there is an abnormality.

  Further, in the measurement method using the OTDR measuring device according to the present invention, the difference between the measured value obtained by measuring the predetermined measurement item with another predetermined measuring means other than the OTDR measuring device is a predetermined reference. If the measured value deviates, it is desirable to determine that there is an abnormality.

  Further, in the measurement method using the OTDR measuring device according to the present invention, the average value of the measured values for a certain period is calculated for each of the OTDR measuring devices, and the difference between the maximum value and the minimum value is determined by a predetermined reference measuring device. If it deviates from the difference, it is desirable to judge that it is abnormal.

  Further, the management method by the OTDR measuring device according to the present invention measures the predetermined measurement item of the reference fiber having a predetermined characteristic value with respect to the predetermined measurement item by using a plurality of OTDR measuring devices, and the measured value and the predetermined value. The characteristic value is compared to determine the presence or absence of abnormality.

  In the management method using the OTDR measuring device configured as described above, a predetermined measurement item is measured for a reference fiber having a predetermined characteristic value using a plurality of OTDR measuring devices. Then, since the measured value is compared with the characteristic value to determine whether or not there is an abnormality, it is possible to prevent the use of an OTDR measuring device that may be abnormal and to improve the measurement accuracy.

  As described above, according to the measurement method using the OTDR measurement device according to the present invention, the measurement of the predetermined measurement item is performed on the reference fiber using the plurality of OTDR measurement devices. Then, it is determined whether there is an abnormality in the measured value. If the measured value is determined to be abnormal, the light source of the OTDR measuring device determined to be abnormal is replaced with a new light source, and the reference is again performed. Measure the fiber to determine the anomaly. As a result, when it is not determined to be abnormal, the measurement of the predetermined item is performed as it is, so that it is possible to prevent the determination of the optical fiber abnormality when there is an abnormality in the measured value due to an abnormality in the light source or the like, High accuracy of measurement can be achieved.

  In addition, a predetermined measurement item is measured for the reference fiber using a plurality of OTDR measuring devices. Then, when it is determined whether or not the measurement value is abnormal, and it is determined that the measurement value is abnormal, the OTDR measurement device in which no abnormality is determined instead of the OTDR measurement device that is determined to be abnormal is determined. Use to measure. For this reason, it is possible to prevent the use of an OTDR measuring device that may be abnormal and to improve the measurement accuracy.

  In addition, measurement of a predetermined measurement item is performed for a reference fiber having a predetermined characteristic value using a plurality of OTDR measuring devices. Since the measured value is compared with the characteristic value to determine whether or not there is an abnormality, it is possible to prevent the use of an OTDR measuring device that may be abnormal and to improve the measurement accuracy.

Embodiments of a measurement method using an OTDR measuring device according to the present invention will be described below in detail with reference to the drawings.
In the first embodiment of the measurement method using the OTDR measuring device according to the present invention, a predetermined measurement item for the reference fiber is measured by a plurality of OTDR measuring devices. For example, as shown in FIG. 1, a plurality of OTDR measuring devices OTDR- Measurement value data measured using 1 to OTDR-n is stored in the measurement value management server 1. Here, for example, the loss value αn (λm and the fiber length Ln measured by the OTDR measuring device) of the wavelength λm in the OTDR measuring device are accommodated as the measurement items.

  Then, the measurement value stored in the measurement value management server 1 is used as needed to determine whether there is an abnormality in the measurement value of a predetermined measurement item. As a result, when an abnormality is determined for one of the OTDR measuring devices, the light source of the OTDR measuring device for which the abnormality is determined is replaced with a new light source, and measurement is performed again using the reference fiber. Judgment is made. And when abnormality is not judged, the subsequent measurement is performed using the said novel light source.

  As a method for determining the above-described abnormality, for example, when the dispersion of the wavelength loss value αn (λm) measured by the OTDR measuring instrument is large and deviates from the reference numerical value range, it can be determined that there is an abnormality. Further, the standard deviation can be used to indicate the magnitude of the variation, and an abnormality can be determined. FIG. 2 (A) shows a case where variation in measured values is considered when the above-described abnormality is predicted. FIG. 2B shows the standard deviation with respect to FIG.

  In FIG. 2A, the standard deviation σ is smaller than the reference value in the range where the variation in the wavelength loss α (λ1) is small, and the standard deviation σ is large in the range where the variation in the wavelength loss α (λ1) is large. Over. As described above, since the variation becomes large in a portion where the standard deviation σ increases and exceeds a preset reference value, it is determined that an abnormality occurs in the OTDR. Alternatively, from the measurement result of FIG. 2 (A), it can be determined that an abnormality with a large direct variation is abnormal.

  As a result, even if the measured value is within the normal range, random fluctuations such as laser output becoming unstable or noise occurring in the measurement waveform due to abnormal dynamic range due to sensor deterioration, etc. are detected. be able to. In addition, when the standard deviation σ is gradually increased by looking at the change over time of the standard deviation σ, it is possible to predict the occurrence of an abnormality in the measuring instrument before actually affecting the measured value. Treatment can be done early.

  FIG. 3 shows a case where an approximate straight line is used instead of the standard deviation or the like when an abnormality is predicted. That is, as shown in FIG. 3, an approximate straight line is calculated from the measurement data within a certain period (for example, one week before the measurement date) for the wavelength loss α (λ1) as a measurement item. Then, the slope of this approximate straight line and the intercept (date) with respect to the reference value are compared with the data up to the previous day. If the slope and intercept are within a certain range, the tendency of fluctuation is constant over time. It is assumed that a certain change has occurred over time, and the occurrence timing of the abnormality is predicted.

That is, as shown in FIG. 4, the standard deviations σA and σB are obtained for the slope A and the intercept B obtained for a certain period (X days), respectively, and when these are below a certain standard, there is little variation, It can be seen that there is regular change with time.
Therefore, even when the measured value is within the normal range, the occurrence timing of the abnormality can be predicted if there is a certain tendency in the slope or intercept. As a result, it is possible to predict the occurrence of an abnormality in the measuring instrument before actually affecting the measurement value, and it is possible to take measures against the abnormality in the measuring instrument early.

  In addition, for a predetermined measurement item, when the difference between another measurement value measured by another predetermined measurement means other than the OTDR measurement device and the measurement value measured by the OTDR measurement device deviates from the predetermined reference measurement value. Can be determined to be abnormal.

  Further, the average value of the measured values for a certain period is calculated for each OTDR measuring device, and the average value by the OTDR measuring device that becomes the maximum (maximum value MAX) and the average value by the OTDR measuring device that becomes the minimum (minimum value MIN). If the difference deviates from the difference of the predetermined reference measuring instrument, it can be determined that there is an abnormality.

  That is, as shown in FIG. 5, the wavelength loss α (λ1), which is a measurement item, is measured by a plurality of OTDRs, and the average of measured values for a single day or a fixed period is compared by each measuring instrument. For example, the maximum value MAX on day X is the measuring device 1, and the minimum value MIN is the measuring device 2. When this difference, MAX-MIN is within a predetermined reference value, it is normal to measure with any measuring instrument, but when the predetermined reference value is exceeded, an abnormality has occurred in the measuring instrument. It is judged.

  As described above, according to the measurement method using the OTDR measurement device according to the present invention, the measurement is performed using the OTDR measurement device, and when the measurement result is determined to be abnormal, the light source is replaced and the measurement is performed again. Since this OTDR measuring instrument is used only when it is determined that there is no abnormality in the OTDR measuring instrument, it is possible to avoid measurement when there is an abnormality in the OTDR measuring instrument. As a result, high accuracy can be guaranteed.

Next, a second embodiment of the measurement method using the OTDR measuring device according to the present invention will be described.
In this measurement method using an OTDR measurement device, a predetermined measurement item for a reference fiber is measured by a plurality of OTDR measurement devices, and whether or not there is an abnormality in the measurement value of the predetermined measurement item is determined. When an abnormality is determined for one of the OTDR measuring devices, the measurement is performed by another OTDR measuring device that has not been determined to be abnormal.
The abnormality determination method is the same as that described in the first embodiment, and a description thereof will be omitted.

  As described above, according to the measurement method using the OTDR measuring device according to the present invention, when it is determined that the OTDR measuring device is abnormal, it is known that there is no abnormality without performing the measurement using the OTDR measuring device. Since the measurement is performed using the existing OTDR measuring device, high-precision measurement can be performed.

Next, a third embodiment of the measurement method using the OTDR measuring device according to the present invention will be described.
In this measurement method using an OTDR measurement device, a predetermined measurement item is measured by a plurality of OTDR measurement devices for a reference fiber having a predetermined characteristic value with respect to the predetermined measurement item. Then, the measured value is compared with a predetermined characteristic value to determine whether there is an abnormality.
The abnormality determination method is the same as that described in the first embodiment, and a description thereof will be omitted.

  As described above, according to the measurement method using the OTDR measurement device according to the present invention, the measurement is performed on the reference fiber whose characteristic value is known, and if the measurement value is different from the reference value of the reference fiber, the OTDR measurement device is abnormal. Judge. Therefore, since measurement is performed using an OTDR measuring device that is known not to be abnormal, high-precision measurement can be performed.

In addition, the measuring method by the OTDR measuring device of this invention is not limited to each embodiment mentioned above, A suitable deformation | transformation, improvement, etc. are possible.
For example, in each of the embodiments described above, the wavelength loss is exemplified as the measurement item, but the present invention is not limited to this.

It is explanatory drawing which shows 1st Embodiment of the measuring method by the OTDR measuring device which concerns on this invention. (A) is a graph which shows a wavelength loss, (B) is a graph which shows the standard deviation of a wavelength loss. It is a graph explaining the method of predicting a regular change with time by an approximate curve and detecting an abnormality. It is a table | surface explaining the method of predicting a regular temporal change from the inclination of an approximated curve, and the dispersion | variation in an intercept, and detecting an abnormality. It is a graph explaining the management method of the measuring device difference between several measuring devices.

Explanation of symbols

A Inclination B Intercept α Wavelength loss (measurement item)
σ Standard deviation MAX Maximum value MIN Minimum value OTDR-i i-th OTDR measuring instrument

Claims (9)

  When a predetermined measurement item for the reference fiber is measured by a plurality of OTDR measuring devices, whether there is an abnormality in the measurement value of the predetermined measuring item, and when an abnormality is determined for one of the OTDR measuring devices If the light source of the OTDR measuring device in which the abnormality is judged is replaced with a new light source, the measurement is performed again with the reference fiber, the presence or absence of abnormality is judged, and if the abnormality is not judged, the measurement of the predetermined measurement item is performed. A measuring method using an OTDR measuring instrument characterized by comprising:   When a predetermined measurement item for the reference fiber is measured by a plurality of OTDR measuring devices, the presence or absence of an abnormality in the measurement value of the predetermined measuring item is determined, and when one of the OTDR measuring devices is determined to be abnormal Is a measurement method using an OTDR measuring device, characterized in that the measurement is performed by an OTDR measuring device in which it is determined that there is no abnormality.   The measurement value is determined to be abnormal when the measured value is out of a predetermined reference numerical value range, and the measured value is out of the predetermined reference numerical value range. 2. A measuring method using the OTDR measuring instrument described in 2.   In each of the OTDR measuring devices, when a change with time of the data of the measurement value in a predetermined period is out of a predetermined range, it is determined that the OTDR measuring device out of the predetermined range is abnormal. The measurement method using the OTDR measuring device according to claim 1 or 2, wherein the measurement method is according to any one of claims 1 and 2.   3. The OTDR according to claim 1, wherein a standard deviation of the data of the measurement value for a predetermined period is calculated, and it is determined that there is an abnormality when the standard deviation deviates from the predetermined reference deviation. Measuring method with a measuring instrument.   2. An approximate straight line of the measured value data for a predetermined period is calculated, and if the slope and intercept deviate from the predetermined reference slope and reference intercept, respectively, it is determined that there is an abnormality. Or the measuring method by the OTDR measuring device described in 2.   It is determined that there is an abnormality when the difference between the measurement value and another measurement value obtained by measuring the predetermined measurement item with another predetermined measurement means other than the OTDR measurement device deviates from the predetermined reference measurement value. The measuring method by the OTDR measuring device according to claim 1 or 2.   An average value of the measured values for a certain period is calculated for each OTDR measuring device, and when the difference between the maximum value and the minimum value deviates from the difference of a predetermined reference measuring device, it is determined that there is an abnormality. The measuring method by the OTDR measuring device according to claim 1 or 2.   Measuring the predetermined measurement item of the reference fiber having a predetermined characteristic value with respect to the predetermined measurement item by using a plurality of OTDR measuring devices, and comparing the measured value with the predetermined characteristic value to determine the presence or absence of an abnormality. A management method using an OTDR measuring device.

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