JP2022146053A - Offset amount determination program, offset amount determination method, and offset amount determination device - Google Patents

Abstract

To determine an offset amount (an origin deviation amount) in temperature measurement (double-end measurement) using an optical fiber, without using a heater.SOLUTION: An acquisition unit acquires signal intensity data of a Stokes component ST obtained as a result of CH1 measurement and signal intensity data of the Stokes component ST obtained as a result of CH2 measurement. Also, a calculation unit 52 sets an offset amount to a value between min and max (Fig.11(b)), and repeats a process (Fig.11(c)) of calculating an amount of transmission loss in each section of an optical fiber 30 from the acquired signal intensity data a plurality of times while varying an offset amount. Then, a determination unit determines the offset amount when the sum of the absolute values of the amounts of transmission loss is the smallest as an origin deviation amount in temperature measurement (double-ended measurement) using the optical fiber.SELECTED DRAWING: Figure 11

Description

The present invention relates to an offset amount determination program, an offset amount determination method, and an offset amount determination device.

2. Description of the Related Art An optical fiber thermometer is known that measures the temperature distribution in the extending direction of an optical fiber using backscattered light from the optical fiber when light is incident on the optical fiber from a light source (see, for example, Patent Document 1, etc.). ).

In addition, by measuring the incident light from both ends of the optical fiber, the effects of irregular loss (attenuation rate) distribution in the optical fiber due to temperature fluctuations and external forces can be corrected, and highly accurate temperature distribution can be measured. A technique called a double-ended method is also known.

In the double-end method, the origin of data measured by entering light from one end of the optical fiber (first measurement data) and the origin of data measured by entering light from the other end of the optical fiber (second measurement data) There is a deviation (offset). Therefore, this offset must be taken into account when measuring the temperature distribution. Conventionally, a technique is known in which a heating device is used to temporarily heat an arbitrary position on an optical fiber, and an offset is set so that the temperature peaks of the first and second measurement data obtained at that time match. there is Also known is a technique of constantly heating the reference section and dynamically adjusting the offset so as to match the peaks of the backward Raman scattered light intensity of the first measurement data and the second measurement data (for example, non-patented Reference 1, etc.).

JP 2014-167399 A

J. Li, Y. Xu, M. J. Zhang, J. Z. Zhang, L. J. Qiao, and T. Wang, “Performance improvement in double-ended RDTS by suppressing the local external physics perturbation and intermodal dispersion,” Chin. Opt. Lett. 17( 7), 070602 (2019).

However, heating the optical fiber using a heating device increases costs and man-hours. Moreover, the above technique cannot be used when the optical fiber is installed in an environment where the heating device cannot be brought into the environment.

In one aspect, the present invention provides an offset amount determination program, an offset amount determination method, and an offset amount that can determine the offset amount when calculating the temperature distribution in the stretching direction of an optical fiber without using a heating device. It is an object to provide a decision device.

In one aspect, the offset amount determination program includes the result of a first measurement of introducing a laser pulse from one end of an optical fiber and measuring the backscattered light scattered at each position of the optical fiber, and the other end of the optical fiber. The first measurement when calculating the temperature distribution in the extending direction of the optical fiber using the result of the second measurement of introducing the laser pulse from and measuring the backscattered light scattered at each position of the optical fiber offset amount determination program for determining the offset amount between the origin of the second measurement and the origin of the second measurement, wherein the computer, from the result of the first measurement, the light amount of the backscattered light scattered at each position of the optical fiber Acquisition of first data indicating the relationship between the predetermined wavelength component and the scattered position, and from the result of the second measurement, the predetermined wavelength component of the light amount of the backscattered light scattered at each position of the optical fiber and Obtaining second data indicating a relationship with scattered positions, assuming that an offset amount between the origin of the first data and the origin of the second data is a predetermined value, and comparing the first data and the second data , the transmission loss calculation process for calculating the transmission loss amount of the optical fiber for each predetermined length section is repeatedly executed a plurality of times while varying the predetermined value, and the sum of the absolute values of the transmission loss amount is a predetermined value. It is an offset amount determination program for executing a process of determining an offset amount when calculating the temperature distribution in the extending direction of the optical fiber based on the predetermined value when the criterion is satisfied.

The offset amount when calculating the temperature distribution in the drawing direction of the optical fiber can be determined without using a heating device.

It is a figure showing roughly composition of a temperature measuring device concerning one embodiment. It is a figure showing the component of backscattered light. It is a figure which shows the hardware constitutions of a processing apparatus. 3 is a functional block diagram of a processing device; FIG. FIGS. 5(a) and 5(b) are diagrams showing the relationship between the elapsed time after light pulse emission by the laser and the light intensity of the Stokes component ST and the anti-Stokes component. FIG. 6(a) is a graph showing the temperature at each position of the optical fiber obtained as a result of the single-ended measurement (CH1), and FIG. 6(b) is a graph showing the temperature of the optical fiber obtained as a result of the single-ended measurement (CH2). FIG. 6(c) is a graph showing the temperature at each position of the optical fiber obtained as a result of the double end measurement. It is a figure for demonstrating the positional deviation of the measurement origin of CH1 and CH2. FIG. 4 is a diagram for explaining a method of calculating a transmission loss amount; 9(a) and 9(b) are diagrams for explaining a case where the offset amount is appropriate, and FIGS. 9(c) and 9(d) are diagrams for explaining a case where the offset amount is not appropriate. It is a diagram for 8 is a flowchart showing an example of processing of an offset amount determining unit; FIG. 11 is a diagram (part 1) for explaining the processing of FIG. 10; FIG. 11 is a diagram (part 2) for explaining the processing of FIG. 10;

An embodiment will be described in detail below with reference to FIGS. 1 to 12(b). FIG. 1 schematically shows the overall configuration of a temperature measurement device 100 according to one embodiment. As shown in FIG. 1, the temperature measuring device 100 includes a measuring device 10, a processing device 20 as an offset amount determining device, an optical fiber 30, and the like. The optical fiber 30 is laid along a predetermined path for temperature measurement. For example, the optical fiber 30 is installed in a server room where many servers are installed, a plant factory, or the like.

The measuring instrument 10 includes a laser 11, a beam splitter 12, an optical switch 13, a filter 14, detectors 15a and 15b, and the like.

The laser 11 is a light source such as a semiconductor laser, and emits laser light within a predetermined wavelength range under the instruction of the instruction unit 40 (see FIG. 4) of the processing device 20 . In this embodiment, the laser 11 emits light pulses (laser pulses) at predetermined time intervals. The beam splitter 12 causes the optical pulse emitted by the laser 11 to enter the optical switch 13 . The optical switch 13 is a switch that switches the emission destination (channel) of the incident optical pulse. In this embodiment, since the temperature distribution in the extending direction of the optical fiber 30 is measured by the double-ended method, the optical switch 13 is set at one end and the other end of the optical fiber 30 under the instruction of the instruction unit 40 of the processing device 20. Light pulses are incident (introduced) alternately at regular intervals.

A light pulse incident on the optical fiber 30 propagates through the optical fiber 30 . At this time, the light pulse propagates through the optical fiber 30 while gradually attenuating while generating forward scattered light traveling in the propagation direction and backscattered light (return light) traveling in the return direction. The generated backscattered light passes through the optical switch 13 and reenters the beam splitter 12 . Backscattered light incident on the beam splitter 12 is emitted to the filter 14 . The filter 14 is a WDM coupler or the like, and extracts a long wavelength component (Stokes component ST to be described later) and a short wavelength component (anti-Stokes component AS to be described later) from the backscattered light.

FIG. 2 is a diagram showing components of backscattered light. As shown in FIG. 2, the backscattered light includes Rayleigh scattered light used in OTDRs (optical pulse testers) and Raman scattered light used in temperature measurement, etc., at wavelengths close to the wavelength of the incident light. Raman scattered light is generated by interference between light and lattice vibrations in the optical fiber 30 that change according to temperature. Constructive interference produces a short wavelength component called the anti-Stokes component AS, and destructive interference produces a long wavelength component called the Stokes component ST.

The detectors 15a and 15b are light receiving elements. The detector 15a converts the received light intensity of the Stokes component ST into an electric signal at a predetermined cycle, and stores the electric signal in the memory processor 42 (see FIG. 4) in the processor 20. FIG. Thereby, the storage processing unit 42 stores the time-series data of the light amount of the Stokes component ST. The detector 15b converts the received light intensity of the anti-Stokes component AS into an electric signal at the same period as the detector 15a, and stores the electric signal in the memory processor 42 in the processor 20. FIG. Thereby, the storage processing unit 42 stores the time-series data of the light amount of the anti-Stokes component AS.

The processing device 20 issues a measurement-related instruction to the measuring device 10 and measures the temperature distribution in the extending direction of the optical fiber 30 based on the data obtained from the measuring device 10 .

FIG. 3 shows the hardware configuration of the processing device 20. As shown in FIG. As shown in FIG. 3, the processing device 20 includes a CPU (Central Processing Unit) 90, a ROM (Read Only Memory) 92, a RAM (Random Access Memory) 94, a storage unit (here, a HDD (Hard Disk Drive) or an SSD ( 96, an input/output interface 97, a portable storage medium drive 99, and the like. Each component of the processing device 20 is connected to the bus 98 . In the processing device 20, the program (including the offset amount determination program) stored in the ROM 92 or the storage unit 96, or the program (including the offset amount determination program) read from the portable storage medium 91 by the portable storage medium drive 99 ) is executed by the CPU 90, the function of each unit shown in FIG. 4 is realized. 4 may be implemented by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

FIG. 4 is a functional block diagram showing functions implemented by the CPU 90 of the processing device 20 executing programs. The processing device 20 has functions as an instruction unit 40 , a storage processing unit 42 , a temperature measurement unit 44 and an offset amount determination unit 46 .

The instruction unit 40 instructs each part of the measuring device 10 to cause the measuring device 10 to perform an operation for acquiring data necessary for measuring the temperature distribution in the extending direction of the optical fiber 30 .

The storage processing unit 42 stores the time-series data of the light intensity of the Stokes component ST and the time-series data of the light intensity of the anti-Stokes component AS sent from the measuring device 10 . FIGS. 5(a) and 5(b) are diagrams showing the relationship between the elapsed time after the laser 11 emits a light pulse and the light intensity of the Stokes component ST and the anti-Stokes component AS. Among them, FIG. 5A shows an example when a first measurement (referred to as channel 1 (CH1) measurement) is performed in which a light pulse is emitted toward one end of the optical fiber 30 . FIG. 5(b) shows an example of performing a second measurement (referred to as channel 2 (CH2) measurement) in which a light pulse is emitted toward the other end of the optical fiber 30. As shown in FIG.

5A and 5B, the elapsed time corresponds to the propagation distance in the optical fiber 30 (position in the optical fiber 30). As shown in FIGS. 5(a) and 5(b), both the light intensity of the Stokes component ST and the anti-Stokes component AS decrease over time. This is due to the light pulse propagating through the optical fiber 30 gradually attenuating while generating forward scattered light and back scattered light.

5(a) and 5(b), the light intensity of the anti-Stokes component AS is stronger at the high temperature position in the optical fiber 30 than the Stokes component ST, and at the low temperature position, the Stokes component AS is stronger. weaker compared to component ST. Therefore, the temperature at each position in the optical fiber 30 can be detected by detecting both components with the detectors 15a and 15b and utilizing the characteristic difference between the two components. In addition, in FIGS. 5(a) and 5(b), the region showing the maximum is a relatively high temperature region. Also, the region showing the minimum is a region of relatively low temperature.

Returning to FIG. 4, the temperature measurement unit 44 measures (calculates) the temperature at each position in the optical fiber 30 from the time-series data of the light intensity of the Stokes component ST and the anti-Stokes component AS stored in the storage processing unit 42. do. That is, the temperature measurement unit 44 measures the temperature distribution in the extending direction of the optical fiber 30 . Further, by repeating the same temperature measurement each time the laser 11 outputs the light pulse, the temperature measurement unit 44 can repeat the measurement of the temperature distribution of the optical fiber 30 at the output cycle of the light pulse. Thereby, the temperature measurement unit 44 can acquire the temporal change of the temperature distribution of the optical fiber 30 .

As shown in FIG. 6(a), the temperature measurement unit 44 measures the temperature of the optical fiber 30 using the time-series data (FIG. 5(a)) of the light intensity of the Stokes component ST and the anti-Stokes component AS obtained by the measurement of CH1. The temperature at each location can be measured. In addition, as shown in FIG. 6(b), the temperature measurement unit 44 uses the time-series data (FIG. 5(b)) of the light intensity of the Stokes component ST and the anti-Stokes component AS obtained by the measurement of CH2 to measure the optical fiber temperature. The temperature at each of the 30 locations can be measured. In addition, the measurement result of FIG.6(b) becomes the same measurement result as FIG.6(a) by right-and-left reversing. These measurement methods are called single-ended measurements. In the single-ended measurement, for example, the temperature can be obtained from the ratio of the light amount of the Stokes component ST and the light amount of the anti-Stokes component AS at each position of the optical fiber 30 .

Furthermore, the temperature measuring unit 44 measures the optical fiber 30 using time-series data (FIGS. 5(a) and 5(b)) of the amount of light of the Stokes component ST and the anti-Stokes component AS obtained by measuring both CH1 and CH2. (see FIG. 6(c)). This measurement is called a double ended measurement. In the double-ended measurement, since the temperature is calculated by integrating the light intensities of the CH1 measurement and the CH2 measurement, the influence of the transmission loss can be removed and highly accurate temperature measurement is possible.

However, when performing double-end measurement, as schematically shown in FIG. 7, the positions of the measurement origins of CH1 and CH2 may be shifted. A highly accurate temperature calculation cannot be performed unless the double-end measurement is performed in consideration of the shift (offset) of the measurement origin. Also, the offset may be, for example, around 5 m, and may vary within a range of approximately 0 to 10 m depending on the measurement environment.

The offset amount determination unit 46 determines the positional deviation amount of the measurement origins of CH1 and CH2 (referred to as origin deviation amount or offset amount) before temperature measurement by the temperature measurement unit 44 or between temperature measurements. Here, in this embodiment, the origin deviation amount (offset amount) is determined by paying attention to the following two premises.
(Premise 1) The optical fiber 30 has a point (fusion point) where the optical fibers are fused and connected, and a large transmission loss occurs near the fusion point.
(Premise 2) In double-ended measurement, it is possible to calculate the transmission loss between any two points of the optical fiber 30.

The transmission loss means the loss of light that is lost while the laser pulse is transmitted through the optical fiber. Transmission loss is caused by material-specific factors (absorption loss, scattering loss), external factors (absorption loss, scattering loss, radiation loss, connection loss), and the like.

For example, the transmission loss between two points [z, z+Δz] of the optical fiber 30 can be calculated from the following equation (1). Here, as shown in FIG. 8, P _s1 (z), P _s2 (z), P _s1 (z+Δz), and P _s2 (z+Δz) in Equation (1) are obtained by measuring point z and point z+Δz by measuring CH1 and CH2. is the amount of light (signal intensity) of the Stokes component ST obtained in .

The details of the calculation method of the transmission loss amount are described in the following papers.
Van de Giesen, N., SC Steele-Dunne, J. Jansen, O. Hoes, MB Hausner, S. Tyler, and J. Selker (2012), Double-ended calibration of fiber-optic Raman spectra distributed temperature sensing data, Sensors, 12(5), 5471-5485

In calculating the transmission loss amount, the signal strength of the anti-Stokes component AS can be used instead of the signal strength of the Stokes component ST.

A strong transmission loss occurs in a very short section near the fusion point. For example, as shown in FIG. 9(a), if the offset amount is appropriate, the position of the fusion point will match between the CH1 measurement and the CH2 measurement. Then, the calculated transmission loss becomes a mountain. On the other hand, if the amount of offset is not appropriate, as shown in FIG. The calculated transmission loss fluctuates greatly up and down. That is, the smaller the sum of the absolute values of the measured transmission loss amounts, the more appropriate the offset amount. Therefore, the offset amount determination unit 46 of the present embodiment determines the offset amount when the total sum of the absolute values of the transmission loss amount is the minimum as the origin deviation amount (offset amount) at the time of temperature measurement.

As shown in FIG. 4 , the offset amount determination unit 46 has an acquisition unit 50 , a calculation unit 52 and a determination unit 54 .

The acquisition unit 50 receives from the storage processing unit 42 the data of the signal intensity (light amount) of the predetermined frequency component (here, the Stokes component ST) obtained by the CH1 measurement and the signal intensity of the Stokes component ST obtained by the CH2 measurement. (Light intensity) data is acquired.

The calculating unit 52 uses the data obtained by the obtaining unit 50 to repeatedly perform transmission loss calculation processing for calculating the amount of transmission loss in each section of the optical fiber 30 while changing the amount of offset.

The determination unit 54 determines the offset amount used by the temperature measurement unit 44 based on the results of the transmission loss calculation process executed by the calculation unit 52 a plurality of times.

(Regarding the processing of the offset amount determination unit 46)
The processing of the offset amount determination unit 46 will be described in detail below with reference to the flowchart of FIG. 10 . The processing in FIG. 10 is executed at the timing before the measuring instrument 10 starts the first measurement or at predetermined time intervals. It is assumed that the measurement device 10 is performing CH1 measurement and CH2 measurement under the instruction of the instruction unit 40 before the process of FIG. 10 is started. It is assumed that the memory processing unit 42 stores the signal intensity data (first data and second data) of the Stokes component ST obtained by the CH1 measurement and the CH2 measurement.

When the process of FIG. 10 is started, first, in step S10, the acquisition unit 50 stores the signal intensity data (first data and second data) of the Stokes component ST obtained by the CH1 measurement and the CH2 measurement in the storage processing unit. 42.

Next, in step S12, the acquisition unit 50 performs noise processing on the acquired signal intensity data.

Next, in step S14, the calculator 52 sets the offset range min, max. FIG. 11(a) schematically shows the offset range. The offset range can be, for example, 0 m to 10 m.

Next, in step S16, the calculator 52 sets the offset value to min. That is, the offset range is the amount of offset between the origin of the signal intensity data (first data) of the Stokes component ST obtained by the CH1 measurement and the origin of the signal intensity data (second data) of the Stokes component ST obtained by the CH2 measurement. is assumed to be the minimum value (min) of FIG. 11(b) shows a state where the offset value is set to min.

Next, in step S18, the calculator 52 calculates the amount of transmission loss in each section of the optical fiber 30 (transmission loss calculation process). Specifically, each section (for example, a section with an interval of 50 cm) is set as shown in FIG.

Next, in step S20, the calculator 52 calculates the sum of the absolute values of the transmission loss amounts in all sections.

Next, in step S22, the calculator 52 determines whether the offset value is max. If the determination in step S22 is negative, the process proceeds to step S24, and the calculator 52 increases the offset value by a predetermined value (for example, 50 cm). FIG. 12(a) shows a state in which the offset value is increased by a predetermined value from the state of FIG. 11(b). After that, the process proceeds to step S18. Then, in step S18, the calculation unit 52 sets each section (for example, a section with an interval of 50 cm) as shown in FIG. . Next, in step S20, the calculator 52 calculates the sum of the absolute values of the transmission loss amounts in all sections. After that, the above processing is repeatedly executed a plurality of times while varying the offset value until the offset value reaches max. Then, when the offset value reaches max, the process proceeds to step S26.

After shifting to step S26, the determination unit 54 specifies the offset value when the sum of the absolute values of the transmission loss amounts is the smallest. That is, the determining unit 54 specifies the offset value when the transmission loss amount appears in a mountain shape as shown in FIG. 9(b). The determination unit 54 determines the specified offset value as the origin deviation amount (offset amount during double-end measurement) used when the temperature measurement unit 44 performs double-end measurement.

All the processing of FIG. 10 is completed by the above.

As described in detail above, according to the present embodiment, the acquiring unit 50 acquires the signal strength data of the Stokes component ST obtained as a result of the CH1 measurement and the signal strength data of the Stokes component ST obtained as a result of the CH2 measurement. and are acquired (S10). Further, the calculation unit 52 sets the offset amount to a value between min and max, and performs the process (S18) of calculating the transmission loss amount of each section of the optical fiber 30 from the acquired signal strength data. Repeat a plurality of times while making them different (S24). Then, the determination unit 54 determines the offset amount when the sum of the absolute values of the transmission loss amounts is the smallest as the origin deviation amount in the double-end measurement by the temperature measurement unit 44 (the offset amount in the double-end measurement) (S26 ). Here, as a method of determining the origin deviation amount (offset amount) in the double end measurement, a method of temporarily heating an arbitrary position of the optical fiber using a heating device is known. In this method, the origin shift amount is determined so that the peak position of the temperature distribution obtained by CH1 measurement and single-ended calculation matches the peak position of the temperature distribution obtained by CH2 measurement and single-ended calculation. In this method, since a heating device is used, the cost and man-hours are required, and there is a possibility that the origin deviation amount cannot be determined in a situation where the heating device cannot be used. On the other hand, in the present embodiment, since the transmission loss at the fusion point of the optical fiber 30 is used to determine the amount of deviation from the origin, no heating device is required. Therefore, the cost and man-hours can be reduced, and the origin deviation amount can be determined even in a situation where the heating device cannot be used.

In the above embodiment, as shown in FIGS. 11(c) and 12(b), the case of calculating the transmission loss amount in the entire range of the optical fiber 30 has been described, but the present invention is not limited to this. . For example, if it is known that a fusion point exists in a certain range of the optical fiber 30, the transmission loss amount may be calculated in the range near the fusion point. As a result, the amount of processing can be reduced, and the origin shift amount can be determined without being greatly affected by transmission loss other than the transmission loss caused by the splicing point.

In the above-described embodiment, the determination unit 54 determines the offset amount when the sum of the absolute values of the transmission loss amounts is minimized as the origin deviation amount in the double-ended measurement by the temperature measurement unit 44. , but not limited to these. For example, a range of offset amounts in which the sum of the absolute values of the transmission loss amounts is less than a predetermined value may be specified, and based on this range, the origin deviation amount in the double-ended measurement by the temperature measurement unit 44 may be determined. More specifically, the center value, average value, or the like of the specified range can be determined as the origin deviation amount.

In the above embodiment, the case where the processing device 20 has the function of the offset amount determination unit 46 has been described. may have.

Note that the processing functions described above can be realized by a computer. In that case, a program is provided that describes the processing contents of the functions that the processing device should have. By executing the program on a computer, the above processing functions are realized on the computer. A program describing the processing content can be recorded in a computer-readable storage medium (excluding carrier waves).

When a program is distributed, it is sold in the form of a portable storage medium such as a DVD (Digital Versatile Disc) or a CD-ROM (Compact Disc Read Only Memory) on which the program is recorded. It is also possible to store the program in the storage device of the server computer and transfer the program from the server computer to another computer via the network.

A computer that executes a program stores, for example, a program recorded on a portable storage medium or a program transferred from a server computer in its own storage device. The computer then reads the program from its own storage device and executes processing according to the program. The computer can also read the program directly from the portable storage medium and execute processing according to the program. In addition, the computer can also execute processing in accordance with the received program each time the program is transferred from the server computer.

The embodiments described above are examples of preferred implementations of the present invention. However, the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention.

In addition, the following additional remarks will be disclosed with respect to the above description of the embodiment.
(Appendix 1) Results of a first measurement in which a laser pulse is introduced from one end of an optical fiber and backscattered light scattered at each position of the optical fiber is measured; The origin of the first measurement and the second measurement when calculating the temperature distribution in the extending direction of the optical fiber using the result of the second measurement of measuring the backscattered light scattered at each position of the optical fiber by An offset amount determination program for determining the offset amount from the origin of
to the computer,
From the result of the first measurement, obtain first data indicating the relationship between the predetermined wavelength component of the light amount of the backscattered light scattered at each position of the optical fiber and the scattered position, and obtain the result of the second measurement. from, obtain second data indicating the relationship between the predetermined wavelength component of the light amount of the backscattered light scattered at each position of the optical fiber and the scattered position,
Assuming that the offset amount between the origin of the first data and the origin of the second data is a predetermined value, using the first data and the second data, the transmission loss of the optical fiber is calculated for each predetermined length section. Repeating the transmission loss calculation process for calculating the amount a plurality of times while varying the predetermined value,
Determining an offset amount when calculating the temperature distribution in the extending direction of the optical fiber based on the predetermined value when the sum of the absolute values of the transmission loss amount satisfies a predetermined criterion. An offset amount determination program characterized by:
(Supplementary note 2) The offset amount determination program according to Supplementary note 1, wherein the transmission loss calculation process calculates the amount of transmission loss within a predetermined length range of the optical fiber.
(Supplementary note 3) The offset amount determination program according to Supplementary note 2, wherein the predetermined length range is a range including the fusion point of the optical fiber.
(Appendix 4) Appendices 1 to 1, characterized in that the predetermined value when the sum of the absolute values of the transmission loss amount is the smallest is determined as the offset amount when calculating the temperature at each position of the optical fiber. 4. The offset amount determination program according to any one of 3.
(Appendix 5) Results of a first measurement in which a laser pulse is introduced from one end of an optical fiber and backscattered light scattered at each position of the optical fiber is measured; The origin of the first measurement and the second measurement when calculating the temperature distribution in the extending direction of the optical fiber using the result of the second measurement of measuring the backscattered light scattered at each position of the optical fiber by An offset amount determination method for determining the offset amount from the origin of
the computer
From the result of the first measurement, obtain first data indicating the relationship between the predetermined wavelength component of the light amount of the backscattered light scattered at each position of the optical fiber and the scattered position, and obtain the result of the second measurement. from, obtain second data indicating the relationship between the predetermined wavelength component of the light amount of the backscattered light scattered at each position of the optical fiber and the scattered position,
Assuming that the offset amount between the origin of the first data and the origin of the second data is a predetermined value, using the first data and the second data, the transmission loss of the optical fiber is calculated for each predetermined length section. Repeating the transmission loss calculation process for calculating the amount a plurality of times while varying the predetermined value,
Determining an offset amount when calculating the temperature distribution in the extending direction of the optical fiber based on the predetermined value when the sum of the absolute values of the transmission loss amounts satisfies a predetermined criterion. An offset amount determination method characterized.
(Appendix 6) Results of a first measurement in which a laser pulse is introduced from one end of an optical fiber and backscattered light scattered at each position of the optical fiber is measured; The origin of the first measurement and the second measurement when calculating the temperature distribution in the stretching direction of the optical fiber using the result of the second measurement of measuring the backscattered light scattered at each position of the optical fiber by An offset amount determination device that determines the offset amount from the origin of
From the result of the first measurement, obtain first data indicating the relationship between the predetermined wavelength component of the light amount of the backscattered light scattered at each position of the optical fiber and the scattered position, and obtain the result of the second measurement. an acquisition unit that acquires second data indicating the relationship between the predetermined wavelength component of the amount of the backscattered light scattered at each position of the optical fiber and the scattered position from the optical fiber;
Assuming that the offset amount between the origin of the first data and the origin of the second data is a predetermined value, using the first data and the second data, the transmission loss of the optical fiber is calculated for each predetermined length section. a calculation unit that repeatedly executes transmission loss calculation processing for calculating the amount a plurality of times while varying the predetermined value;
a determination unit that determines an offset amount when calculating the temperature distribution in the extending direction of the optical fiber, based on the predetermined value when the sum of the absolute values of the transmission loss amounts satisfies a predetermined criterion. quantity determination device.
(Supplementary note 7) The offset amount determination device according to Supplementary note 6, wherein the transmission loss calculation process calculates the transmission loss amount within a predetermined length range of the optical fiber.
(Supplementary note 8) The offset amount determination device according to Supplementary note 7, wherein the predetermined length range is a range including the fusion point of the optical fiber.
(Supplementary note 9) The determination unit determines the predetermined value when the sum of the absolute values of the transmission loss amount is the smallest as the offset amount when calculating the temperature at each position of the optical fiber. The offset amount determination device according to any one of appendices 6 to 8.

20 processing device (offset amount determination device)
50 acquisition unit 52 calculation unit 54 determination unit

Claims (6)

results of a first measurement of introducing a laser pulse from one end of an optical fiber and measuring backscattered light scattered at each location in said optical fiber; The difference between the origin of the first measurement and the origin of the second measurement when calculating the temperature distribution in the extending direction of the optical fiber using the result of the second measurement that measures the backscattered light scattered at each position of An offset amount determination program for determining an offset amount,
to the computer,
From the result of the first measurement, obtain first data indicating the relationship between the predetermined wavelength component of the light amount of the backscattered light scattered at each position of the optical fiber and the scattered position, and obtain the result of the second measurement. from, obtain second data indicating the relationship between the predetermined wavelength component of the light amount of the backscattered light scattered at each position of the optical fiber and the scattered position,
Assuming that the offset amount between the origin of the first data and the origin of the second data is a predetermined value, using the first data and the second data, the transmission loss of the optical fiber is calculated for each predetermined length section. Repeating the transmission loss calculation process for calculating the amount a plurality of times while varying the predetermined value,
Determining an offset amount when calculating the temperature distribution in the extending direction of the optical fiber based on the predetermined value when the sum of the absolute values of the transmission loss amount satisfies a predetermined criterion. An offset amount determination program characterized by: 2. The offset amount determination program according to claim 1, wherein the transmission loss calculation process calculates the transmission loss amount within a predetermined length range of the optical fiber. 3. The offset amount determination program according to claim 2, wherein said predetermined length range is a range including the fusion point of said optical fiber. 4. The method according to any one of claims 1 to 3, wherein the predetermined value when the sum of the absolute values of the transmission loss amounts is the smallest is determined as the offset amount when calculating the temperature at each position of the optical fiber. 1. The offset amount determination program according to 1. results of a first measurement of introducing a laser pulse from one end of an optical fiber and measuring backscattered light scattered at each location in said optical fiber; The difference between the origin of the first measurement and the origin of the second measurement when calculating the temperature distribution in the extending direction of the optical fiber using the result of the second measurement that measures the backscattered light scattered at each position of An offset amount determination method for determining an offset amount,
the computer
From the result of the first measurement, obtain first data indicating the relationship between the predetermined wavelength component of the light amount of the backscattered light scattered at each position of the optical fiber and the scattered position, and obtain the result of the second measurement. from, obtain second data indicating the relationship between the predetermined wavelength component of the light amount of the backscattered light scattered at each position of the optical fiber and the scattered position,
Assuming that the offset amount between the origin of the first data and the origin of the second data is a predetermined value, using the first data and the second data, the transmission loss of the optical fiber is calculated for each predetermined length section. Repeating the transmission loss calculation process for calculating the amount a plurality of times while varying the predetermined value,
Determining an offset amount when calculating the temperature distribution in the extending direction of the optical fiber based on the predetermined value when the sum of the absolute values of the transmission loss amounts satisfies a predetermined criterion. An offset amount determination method characterized. results of a first measurement of introducing a laser pulse from one end of an optical fiber and measuring backscattered light scattered at each location in said optical fiber; The difference between the origin of the first measurement and the origin of the second measurement when calculating the temperature distribution in the extension direction of the optical fiber using the result of the second measurement that measures the backscattered light scattered at each position of An offset amount determination device that determines an offset amount,
From the result of the first measurement, obtain first data indicating the relationship between the predetermined wavelength component of the light amount of the backscattered light scattered at each position of the optical fiber and the scattered position, and obtain the result of the second measurement. an acquisition unit that acquires second data indicating the relationship between the predetermined wavelength component of the amount of the backscattered light scattered at each position of the optical fiber and the scattered position from the optical fiber;
Assuming that the offset amount between the origin of the first data and the origin of the second data is a predetermined value, using the first data and the second data, the transmission loss of the optical fiber is calculated for each predetermined length section. a calculation unit that repeatedly executes transmission loss calculation processing for calculating the amount a plurality of times while varying the predetermined value;
a determination unit that determines an offset amount when calculating the temperature distribution in the extending direction of the optical fiber, based on the predetermined value when the sum of the absolute values of the transmission loss amounts satisfies a predetermined criterion. quantity determination device.

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