JP5564586B1 - measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure optical power for each of a plurality of optical fiber core wires in a series of tests by OTDR. Therefore, the measurement time becomes long.
An optical pulse output unit for inputting an optical pulse to each of incident ends of a plurality of optical fiber core wires, and a plurality of optical fiber core wires corresponding to the optical pulses incident on each of the plurality of optical fiber core wires. A measuring unit that measures the optical power of the backscattered light from a plurality of positions at different distances from the incident end, and the measuring unit is a backscattered light from each of the plurality of optical fiber core wires. A plurality of photoelectric conversion units that have a light receiving unit that receives scattered light, the light receiving unit is provided corresponding to each of the plurality of optical fiber core wires, and converts back scattered light from the corresponding optical fiber core wires into electric signals Have
[Selection] Figure 1

Description

  The present invention relates to a measuring apparatus and a measuring method.

A method for detecting an abnormality of an optical fiber using OTDR is known (see Patent Documents 1 to 4). In patent document 4, the optical power of the backscattered light about each of several wavelengths is measured, and the abnormal location is specified from the inclination of the wavelength versus loss characteristic of an optical fiber core wire.
(Prior art documents)
(Patent Literature)
(Patent Document 1) JP 2011-047914 (Patent Document 2) JP 2011-038785 (Patent Document 3) JP 2005-337766 (Patent Document 4) JP 2009-175743

  In a series of tests by OTDR, each optical power of a plurality of optical fiber core wires is measured in order. Therefore, the time required for measuring all the optical fiber core wires becomes longer.

  According to the first aspect of the present invention, the optical pulse output unit that inputs the optical pulse to each of the incident ends of the plurality of optical fiber core wires, and the optical pulse that is input to each of the plurality of optical fiber core wires. A measuring unit that measures the optical power of backscattered light from a plurality of positions, each of which is backscattered light from each of the plurality of optical fiber core wires and having different distances from the incident end. A light receiving unit that receives backscattered light from each of the fiber cores is provided corresponding to each of the plurality of optical fiber cores, and the backscattered light from the corresponding optical fiber cores is converted into an electrical signal. A measuring device having a plurality of photoelectric conversion units for conversion is provided.

  In the measurement apparatus, the measurement unit may further include a plurality of optical demultiplexing units provided corresponding to each of the plurality of optical fiber core wires. The optical pulse output unit may alternately input the first optical pulse having the first wavelength and the second optical pulse having the second wavelength to each of the incident ends of the plurality of optical fiber core wires. Each of the plurality of optical demultiplexing units is a backscattered light from the corresponding optical fiber core line, and corresponds to each of the first optical pulse and the second optical pulse, and has a plurality of different distances from the incident end. The backscattered light from the position may be demultiplexed into light having the first wavelength and light having the second wavelength. The light receiving unit is provided corresponding to each of the plurality of optical demultiplexing units, and a plurality of first photoelectric conversions that convert the light having the first wavelength demultiplexed by the corresponding optical demultiplexing unit into an electric signal And a plurality of second photoelectric conversion units provided corresponding to each of the plurality of optical demultiplexing units and converting light having the second wavelength demultiplexed by the corresponding optical demultiplexing units into an electric signal And may include.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

An example of measuring device 100 is shown roughly. An example of the optical pulse output part 110 is shown schematically. An example of the optical pulse output part 310 is shown schematically. An example of the optical pulse output unit 410 is schematically shown. An example of measuring device 500 is shown roughly. An example of the light-receiving part 542 is shown schematically. An example of optical pulse output part 510 is shown roughly. An example of the optical pulse output unit 810 is schematically shown. An example of the optical pulse output unit 910 is schematically shown.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Not all the combinations of features described in the embodiments are essential for the solution of the invention. In addition, embodiments will be described with reference to the drawings, but in the description of the drawings, the same or similar parts may be denoted by the same reference numerals and redundant description may be omitted. Further, the technical matters described in relation to a specific embodiment may be applied to other embodiments as long as there is no technical contradiction.

  FIG. 1 schematically shows an example of a measuring apparatus 100. In FIG. 1, the measurement apparatus 100 will be described by taking as an example a case where an abnormality of a plurality of optical fiber core wires including the optical fiber core wire 12, the optical fiber core wire 14, and the optical fiber core wire 16 is detected using the measurement apparatus 100. Measuring device 100 may be an optical time domain reflectometer (sometimes referred to as OTDR).

  First, an outline of the measuring apparatus 100 will be described. The measuring apparatus 100 allows test light to enter the optical fiber core wire from one end of the optical fiber core wire (sometimes referred to as an incident end), and enters the incident end from a plurality of positions at different distances from the incident end of the optical fiber core wire. The optical power of the backscattered light returning to is detected at the incident end. Using the optical power of the backscattered light detected at the incident end and the time until the backscattered light returns to the incident end after the test light is incident on the incident end, the light is incident on the optical fiber core wire. Information on the optical power of the backscattered light at each position of the optical fiber core wire of the test light is obtained. The measurement of the optical power of the backscattered light is performed a plurality of times for the test light of each wavelength. By averaging a plurality of measurement results, the influence of noise can be reduced.

  By acquiring information related to the optical power of backscattered light at each position of the optical fiber core line, the absolute value of the amount of change in optical power per unit distance (sometimes referred to as optical loss) increases rapidly. It can be inferred that some abnormality has occurred at a certain position. Examples of causes of a sudden change in optical power (sometimes referred to as abnormal light loss) include bending of the optical fiber core and misalignment due to poor fusion connection of the optical fiber core.

  The measuring apparatus 100 relates to the optical power of backscattered light at each position of the optical fiber core line for each of a plurality of wavelengths by changing the wavelength of the test light or using test light including light of a plurality of wavelengths. Get information. For each of a plurality of wavelengths, by obtaining information on the optical power of the backscattered light at each position of the optical fiber core wire, a plurality of wavelengths and a change in optical power at a specific location of the optical fiber core wire at each of the plurality of wavelengths A wavelength-loss characteristic showing the relationship with the quantity is obtained. Using the slope of the wavelength versus loss characteristic, it is possible to infer the cause of the abnormality at the location where the abnormal light loss occurs.

  In this embodiment, the measuring apparatus 100 measures the optical power of backscattered light for each of the plurality of optical fiber core wires. In one embodiment, the measuring apparatus 100 makes the light pulses of the test light incident on all the optical fiber core wires to be tested almost simultaneously. In another embodiment, the measuring apparatus 100 switches all the optical fiber core wires to be tested during one cycle of the optical pulse while sequentially switching the optical fiber core wires to which the optical pulse of the test light is incident. On the other hand, an optical pulse is incident.

  According to any of the above embodiments, information regarding the optical power of the backscattered light regarding each of the plurality of optical fiber core wires can be acquired in a short time. By acquiring information on the optical power of backscattered light for each of a plurality of optical fiber core wires in a short time, the influence on the measurement results due to changes in the surrounding environment of the optical fiber core wire during the measurement period can be reduced. .

  Next, each part of the measuring apparatus 100 will be described. In the present embodiment, the measurement apparatus 100 includes an optical pulse output unit 110, a plurality of optical multiplexers / demultiplexers including an optical multiplexer / demultiplexer 112, an optical multiplexer / demultiplexer 114, and an optical multiplexer / demultiplexer 116, and a measurement unit 120. . Each of the plurality of optical multiplexers / demultiplexers is provided corresponding to each of the plurality of optical fiber core wires.

  The measurement unit 120 includes a light receiving unit 142, a signal processing unit 144, and a control unit 146. The light receiving unit 142 includes a plurality of photoelectric conversion units including a photoelectric conversion unit 152, a photoelectric conversion unit 154, and a photoelectric conversion unit 156. Each of the plurality of photoelectric conversion units is provided corresponding to each of the plurality of optical fiber core wires. The measurement unit 120 may include an input unit 162 and a notification unit 164.

  The optical pulse output unit 110 makes an optical pulse incident on each of incident ends of a plurality of optical fiber core wires. The optical pulse output unit 110 may output a plurality of types of optical pulses having different wavelengths. The optical pulse output unit 110 may perform a plurality of measurements using an optical pulse having the second wavelength after performing a plurality of measurements using the optical pulse having the first wavelength. The optical pulse output unit 110 may alternately output the optical pulse having the first wavelength and the optical pulse having the second wavelength to perform the measurement a plurality of times. When the optical pulse output unit 110 alternately outputs the optical pulse having the first wavelength and the optical pulse having the second wavelength, each of the plurality of optical multiplexers / demultiplexers and the plurality of photoelectric conversion units It is preferable to provide a plurality of wavelength demultiplexers for demultiplexing light of a plurality of wavelengths included in the plurality of backscattered light.

  The optical multiplexer / demultiplexer 112, the optical multiplexer / demultiplexer 114, and the optical multiplexer / demultiplexer 116 are provided corresponding to the optical fiber core line 12, the optical fiber core line 14, and the optical fiber core line 16, respectively. Each of the optical multiplexer / demultiplexer 112, the optical multiplexer / demultiplexer 114, and the optical multiplexer / demultiplexer 116 is provided between the optical pulse output unit 110 and the corresponding optical fiber core wire. Each of the optical multiplexer / demultiplexer 112, the optical multiplexer / demultiplexer 114, and the optical multiplexer / demultiplexer 116 is provided between the light receiving unit 142 and the corresponding optical fiber core wire.

  The optical pulse from the optical pulse output unit 110 is input to each of the optical multiplexer / demultiplexer 112, the optical multiplexer / demultiplexer 114, and the optical multiplexer / demultiplexer 116. Each of the optical multiplexer / demultiplexer 112, the optical multiplexer / demultiplexer 114, and the optical multiplexer / demultiplexer 116 outputs the input optical pulse to the optical fiber core line 12, the optical fiber core line 14, and the optical fiber core line 16.

  Back scattered light from the optical fiber core line 12, the optical fiber core line 14, and the optical fiber core line 16 is input to each of the optical multiplexer / demultiplexer 112, the optical multiplexer / demultiplexer 114, and the optical multiplexer / demultiplexer 116. Each of the optical multiplexer / demultiplexer 112, the optical multiplexer / demultiplexer 114, and the optical multiplexer / demultiplexer 116 outputs the input backscattered light to the photoelectric conversion unit 152, the photoelectric conversion unit 154, and the photoelectric conversion unit 156.

  The measurement unit 120 is backscattered light from each of a plurality of optical fiber cores corresponding to an optical pulse incident on each of the plurality of optical fiber cores, and is back from a plurality of positions at different distances from the incident end. Measure the optical power of the scattered light. The measurement unit 120 may determine a location where an abnormal light loss occurs. The measurement unit 120 may determine the cause of the abnormality at the location where the abnormal light loss occurs.

  The light receiving unit 142 receives backscattered light from each of the plurality of optical fiber core wires and converts it into an electrical signal. Each of the photoelectric conversion unit 152, the photoelectric conversion unit 154, and the photoelectric conversion unit 156 is provided corresponding to each of the optical fiber core wire 12, the optical fiber core wire 14, and the optical fiber core wire 16. Each of the photoelectric conversion unit 152, the photoelectric conversion unit 154, and the photoelectric conversion unit 156 receives backscattered light from the corresponding optical fiber core wire. Each of the photoelectric conversion unit 152, the photoelectric conversion unit 154, and the photoelectric conversion unit 156 converts the received backscattered light into an electrical signal. Each of the photoelectric conversion unit 152, the photoelectric conversion unit 154, and the photoelectric conversion unit 156 transmits an electrical signal obtained by converting the backscattered light to the signal processing unit 144.

  The signal processing unit 144 performs A / D conversion on the electrical signal received from the light receiving unit 142. The signal processing unit 144 measures the optical power of the backscattered light based on the A / D converted amplitude data. The signal processing unit 144 determines from which position in the optical fiber core the backscattered light based on the time from when the optical pulse is output from the optical pulse output unit 110 to when it returns to the incident end. To do. The signal processing unit 144 performs the above processing on the electrical signal received from each of the plurality of photoelectric conversion units. Thereby, loss distribution in each of a plurality of optical fiber core wires is acquirable.

The signal processing unit 144 may determine an abnormal location by specifying a location where an abnormal optical loss occurs in each loss distribution of the plurality of optical fiber core wires. The signal processing unit 144 may determine the cause of the abnormality at the location where the abnormal light loss occurs. For example, the signal processing unit 144 may determine the cause of the abnormality by calculating a macro bending index k _macro at a location where an abnormal light loss occurs. When the value of the macro bending index k _macro is positive, the signal processing unit 144 may determine that an abnormal bend has occurred in the optical fiber core wire. When the value of the macro bending index k _macro is negative, the signal processing unit 144 may determine that an axis deviation due to poor fusion connection has occurred.

The macro bending index k _macro can be calculated by the following equation (1).
k _macro = {Loss (λ ₂ ) −Loss (λ ₁ )} / (λ ₂ −λ ₁ ) (Formula 1)
In Equation 1, λ ₁ and λ ₂ represent the wavelength [nm] of the test light that is incident on the optical fiber core wire and the optical power of the backscattered light is measured. Loss (λ ₁ ) represents the amount of light loss [dB] at a specific location of the optical fiber core wire when the wavelength of the test light is λ ₁ . Loss (λ ₂ ) represents the amount of light loss [dB] at a specific location of the optical fiber core wire when the wavelength of the test light is λ ₂ . The macro bending index k _macro represents the slope of the wavelength versus loss characteristic. As is clear from Equation 1, even if the data when the wavelength of the test light is λ ₁ and the data when the wavelength of the test light is λ ₂ are exchanged, the macro bending index k _macro is not affected. Therefore, the program for determining at least one of the abnormal part and the cause of the abnormality can be simplified by using the macro bending index k _macro as an index for determining at least one of the abnormal part and the abnormal cause. Moreover, the influence on the output result of the program by the user's input mistake can be reduced.

  The wavelength versus loss characteristic indicates the relationship between a plurality of wavelengths and the amount of change in optical power at a specific location of the optical fiber core wire at each of the plurality of wavelengths. The wavelength versus loss characteristic represents the wavelength dependence of the amount of change in optical power at a specific location of the optical fiber core wire. The wavelength-to-loss characteristics are, for example, the wavelength value obtained by measuring the optical power of the backscattered light with the horizontal axis representing the wavelength, and the vertical axis representing the amount of change in the optical power at a specific position of the optical fiber core line, and the optical power at the wavelength. It can be determined by plotting the relationship with the amount of change. The method for determining the wavelength-to-loss characteristic is not particularly limited as long as it is a method that can acquire the correspondence between each of a plurality of wavelengths and the amount of change in optical power at each wavelength.

  The control unit 146 controls operations of the optical pulse output unit 110 and the measurement unit 120. The control unit 146 may receive information from the input unit 162. The control unit 146 may transmit information to the notification unit 164. The control unit 146 may be realized by hardware, may be realized by software, or may be realized by a combination of hardware and software. Further, the computer may function as a part of the control unit 146 by executing the program. The program may be stored in a computer-readable medium, or may be stored in a storage device connected to a network.

  The control unit 146 may be realized by activating software or a program that defines the operation of each unit of the control unit 146 in an information processing apparatus having a general configuration. The information processing device used as the control unit 146 includes a data processing device having a CPU, a ROM, a RAM, a communication interface, an input device such as a keyboard, a touch panel, and a microphone, and an output device such as a display device, a speaker, and a vibration device. And a storage device such as a memory or an HDD.

  The controller 146 may determine the output pattern of the light pulse from the light pulse output unit 110. As an output pattern of the optical pulse from the optical pulse output unit 110, a pattern in which the optical pulse output unit 110 outputs optical pulses almost simultaneously to all of the plurality of optical fiber core wires to be tested (first pattern). The optical pulse output unit 110 sequentially outputs the optical pulses so that the timings at which the optical pulses are incident on the plurality of optical fiber cores to be tested do not overlap each other (the first pattern). 2), so that the timing at which the optical pulse output unit 110 enters the optical pulses to some of the optical fiber cores among the plurality of optical fiber cores to be tested overlaps. An example is a pattern in which optical pulses are sequentially output (sometimes referred to as a third pattern).

  The control unit 146 may determine parameters for controlling the operations of the optical pulse output unit 110 and the measurement unit 120. The controller 146 includes a number N of optical fiber core wires (N is an integer of 1 or more), a pulse width tw of an optical pulse, a period T of an optical pulse, and a wavelength number m (m is an integer of 1 or more). .) The maximum value of at least one of the number N of optical fiber core wires and the pulse width tw of the optical pulse may be determined based on at least one output pattern of the optical pulse.

  The number of wavelengths m indicates the number of wavelengths of light used for the test light, and indicates how many types of optical pulses with different wavelengths are included in the optical pulses output during the period T. For example, the optical pulse output unit 110 performs a plurality of measurements using an optical pulse having a period T and a first wavelength, and then performs a plurality of measurements using an optical pulse having a period T and a second wavelength. In the case of performing the above, one light pulse is output during the period T. In this case, m = 1. In the case where the optical pulse output unit 110 alternately outputs the optical pulse having the period T and the first wavelength and the optical pulse having the period T and the second wavelength to perform the measurement a plurality of times. When the delay amount of the optical pulse having the second wavelength with respect to the optical pulse having the first wavelength is shorter than the period T, the optical pulse having the first wavelength and the second wavelength during the period T One light pulse having each of is output. In this case, m = 2.

  When at least one of the number N of the plurality of optical fiber core wires and the pulse width tw of the optical pulse is larger than the determined maximum value, the control unit 146 notifies the user or the maximum value via the notification unit 164. May be notified. Further, the control unit 146 may prompt the user to change the setting of the number N of the plurality of optical fiber core wires and the pulse width tw of the optical pulse via the notification unit 164. For example, when the number N of the plurality of optical fiber core wires is larger than the maximum value, the control unit 146 notifies the user so that the number of optical fiber core wires to be tested is equal to or less than the maximum value. In this case, the measuring apparatus 100 measures a plurality of optical fiber core wires in a plurality of times.

  When the pulse width tw of the optical pulse is larger than the determined maximum value, the control unit 146 may limit the input from the input unit 162 so that the input from the input unit 162 is equal to or less than the maximum value. Good. The controller 146 may increase at least one of the number of measurements and the optical power of the optical pulse after setting the pulse width tw of the optical pulse to the maximum value.

  For example, when the output pattern of the optical pulse is the second pattern, the control unit 146 sets at least the number N of the plurality of optical fiber core wires and the pulse width tw of the optical pulse so that m × N × tw <T. Decide one. For example, when the output pattern of light pulses is the third pattern, the timing of outputting m light pulses having different wavelengths can be overlapped. In this case, the control unit 146 may determine at least one of the number N of the plurality of optical fiber core wires and the pulse width tw of the optical pulse so that N × tw <T.

  The input unit 162 receives input from the user. For example, the input unit 162 receives an input regarding at least one of the period T of the optical pulse and the pulse width tw of the optical pulse. The input unit 162 may be a keyboard, a touch panel, a microphone, or the like.

  The period T of the light pulse may be determined based on the length of the optical fiber core wire to be tested. For example, if the length of the optical fiber core wire is long, a large value is set as the period T of the optical pulse. The pulse width tw of the optical pulse may be determined based on the optical power of the optical pulse and the required distance resolution. For example, if the demand for resolution is high, a small value is set as the pulse width tw of the optical pulse. If the optical power of the optical pulse is small, a large value may be set as the pulse width tw of the optical pulse.

  The notification unit 164 notifies the user of information. The notification unit 164 may be a display device, a speaker, a vibration device, or the like.

  FIG. 2 schematically shows an example of the optical pulse output unit 110. In the present embodiment, the optical pulse output unit 110 includes a light source 210, an optical splitter 220, and a pulse generator 230 that generates a pulse signal. In the present embodiment, the optical pulse output unit 110 outputs optical pulses almost simultaneously to all of the plurality of optical fiber cores to be tested.

  The light source 210 generates light. A pulse signal is input from the pulse generator 230 to the light source 210. The light source 210 may generate light pulses by generating light based on the input pulse signal. The light source 210 may generate light with a specific wavelength, or may change the wavelength of the generated light.

  Light from the light source 210 is input to the optical splitter 220. The optical branching device 220 branches the input light and outputs it to each of the plurality of optical multiplexers / demultiplexers. Thereby, an optical pulse is incident on each of the plurality of optical fiber core wires.

  FIG. 3 schematically shows an example of the optical pulse output unit 310. The optical pulse output unit 310 is different from the optical pulse output unit 110 described with reference to FIG. 2 in that an optical pulse is generated using an optical switch. In the present embodiment, the optical pulse output unit 310 outputs optical pulses almost simultaneously to all of the plurality of optical fiber core wires to be tested.

  In the present embodiment, the optical pulse output unit 310 includes a plurality of light including a light source 210, an optical branching device 220, a pulse generator 230, a signal branching device 340, an optical switch 352, an optical switch 354, and an optical switch 356. And a switch. The plurality of optical switches are provided corresponding to each of the plurality of optical fiber core wires. The pulse generator 230 may be an example of a drive signal generation unit that generates a drive signal for driving each of the plurality of optical switches.

  The pulse signal from the pulse generator 230 is input to the signal branching unit 340. The signal branching device 340 branches the input pulse signal and outputs it to a plurality of optical switches.

  Each of the optical switch 352, the optical switch 354, and the optical switch 356 is provided corresponding to each of the optical fiber core wire 12, the optical fiber core wire 14, and the optical fiber core wire 16. Each of the optical switch 352, the optical switch 354, and the optical switch 356 is provided between the optical branching device 220 and the corresponding optical fiber core wire. Each of the optical switch 352, the optical switch 354, and the optical switch 356 switches whether the light from the light source 210 is incident on the corresponding optical fiber core wire.

  Each of the optical switch 352, the optical switch 354, and the optical switch 356 includes an input terminal to which light from the light source 210 is input, and an optical fiber core line that corresponds to the light input to the input terminal when connected to the input terminal. And a drive terminal to which a pulse signal from the pulse generator 230 is input. Each of the optical switch 352, the optical switch 354, and the optical switch 356 outputs an optical pulse by switching the connection state between the input terminal and the output terminal based on the pulse signal input to the drive terminal.

  For example, each of the plurality of optical switches connects the input terminal and the output terminal when the input pulse signal is H logic, and outputs light input to the input terminal from the output terminal. In addition, each of the plurality of optical switches does not connect the input terminal and the output terminal when the input pulse signal is L logic.

  FIG. 4 schematically shows an example of the optical pulse output unit 410. The optical pulse output unit 410 is different from the optical pulse output unit 310 described in relation to FIG. 3 in that an optical pulse is generated using an optical switch having a plurality of output terminals for one input terminal. To do. A PLZT high-speed optical switch manufactured by Epiphotonics Co., Ltd. may be used as an optical switch having a plurality of output terminals for one input terminal. In the present embodiment, the optical pulse output unit 410 sequentially outputs optical pulses so that the timings at which the optical pulses are incident on a plurality of optical fiber cores to be tested do not overlap each other.

  In the present embodiment, the optical pulse output unit 410 includes a light source 210, a pulse generator 230, a signal branching unit 340, an optical switch 450, a delay unit 462, a delay unit 464, and a delay unit 466. With. In the present embodiment, the signal branching device 340 branches the input pulse signal and outputs the branched pulse signal to each of the plurality of delay devices.

  The optical switch 450 has an input terminal IT1, a plurality of output terminals including an output terminal OT1, an output terminal OT2, and an output terminal OTN, and a plurality of drive terminals including a drive terminal DT1, a drive terminal DT2, and a drive terminal DTN. Each of the plurality of output terminals is provided corresponding to each of the plurality of optical fiber core wires. Each of the plurality of drive terminals is provided corresponding to each of the plurality of output terminals.

  Each of the plurality of delay devices is provided corresponding to each of the plurality of drive terminals. Each of the plurality of delay devices is provided between the pulse generator 230 and each of the plurality of drive terminals. A pulse signal from the pulse generator 230 is input to each of the plurality of delay units via the signal branching unit 340. Each of the plurality of delay devices delays the input pulse signal and outputs it to the corresponding drive terminal. The delay device may be an example of a delay unit.

  The amount of delay in each of the plurality of delay units may be determined by the control unit 146. The controller 146 delays so that only one of the plurality of drive terminals is supplied with one of H logic or L logic and the other drive terminal is supplied with the other of H logic or L logic. The amount may be determined.

The control unit 146 may determine a delay amount in each of the plurality of delay devices based on the number N of the plurality of optical fiber core wires, the period T of the optical pulse, and the pulse width tw of the optical pulse. The control by the control unit 146 is an example in which the output pattern of the optical pulse is the second pattern and m × N optical pulses are output at regular intervals from the light source 210 in the period corresponding to the period T. explain. In this case, assuming that the time interval of the optical pulse input to the input terminal IT1 is t _P , the delay amounts in the delay unit 462, the delay unit 464, and the delay unit 466 are 0, tw + t _P and 2 × (tw + t _P ), respectively. It becomes. The time interval t _P indicates the time from when the optical pulse input to the input terminal IT1 becomes L logic to the next H logic.

In the above case, the control unit 146 may determine the time interval t _P so that m × {N × tw + (N−1) × t _P } <T. For example, after the optical pulse output unit 410 performs a plurality of measurements using an optical pulse having a period T and a first wavelength, the optical pulse output unit 410 uses the optical pulse having a period T and a second wavelength to perform a plurality of times. When performing the measurement of (i.e., when m = 1), the control unit 146 may determine the time interval t _P such that N × tw + (N−1) × t _P <T. Control unit 146 determines the time based on the interval t _P, it may determine the amount of delay in each of the plurality of delay devices.

Similarly, the output pattern of the optical pulses is the third pattern, m optical pulses having different wavelengths are output at the same timing, and m × N optical pulses are output at regular intervals during the period T. (That is, when N optical pulses are output at equal intervals during the period T for each wavelength), the control unit 146 satisfies N × tw + (N−1) × t _P <T. In addition, the time interval t _P may be determined.

It should be noted that the time interval t _P may be zero. Even the time interval t _P is 0, an output destination of light pulses, by sequentially switching from the output terminal OT1 to the output terminal OTN, in each of the plurality of optical fiber core, the optical pulse does not collide. Further, it is preferable that the time interval t _P are equally spaced, the time interval t _P between at least a portion of the light pulses may be different from the time interval t _P between other optical pulses. For example, when light pulses are sequentially incident from the optical fiber core line 12 to the optical fiber core line 16 and then repeatedly incident from the optical fiber core line 12 to the optical fiber core line 16 again, the optical pulse is the optical fiber core line 12. The time interval t _P between the incident light beams from the optical fiber core line 16 to the optical fiber core line 16 is an equal interval, and the optical pulse incident on the optical fiber core line 12 after the optical pulse incident on the optical fiber core line 16 becomes L logic. The time interval t _P until “H” becomes H logic may be zero.

  The optical switch 450 switches whether or not the light from the light source 210 is incident on each of the plurality of optical fiber core wires. Light from the light source 210 is input to the input terminal IT1. The output terminal OT1, the output terminal OT2, and the output terminal OTN are provided corresponding to the optical fiber core wire 12, the optical fiber core wire 14, and the optical fiber core wire 16, respectively. When each of the output terminal OT1, the output terminal OT2, and the output terminal OTN is connected to the input terminal IT1, the light input to the input terminal IT1 is output to the corresponding optical fiber core wire.

  The drive terminal DT1, the drive terminal DT2, and the drive terminal DTN are provided corresponding to the output terminal OT1, the output terminal OT2, and the output terminal OTN, respectively. The pulse signal from the pulse generator 230 is input to each of the drive terminal DT1, the drive terminal DT2, and the drive terminal DTN via the delay unit 462, the delay unit 464, and the delay unit 466, respectively.

  The optical switch 450 connects the input terminal IT1 and an output terminal corresponding to each of the plurality of drive terminals based on a pulse signal input to each of the plurality of drive terminals via each of the plurality of delay devices. By switching the state, an optical pulse is output. For example, when the pulse signal input to the drive terminal DT1 is H logic and the pulse signals input to the other drive terminals are L logic, the optical switch 450 connects the input terminal IT1 and the output terminal OT1. Then, the light input to the input terminal IT1 is output from the output terminal OT1.

  FIG. 5 schematically shows an example of the measuring apparatus 500. In the present embodiment, the measuring apparatus 500 alternately outputs an optical pulse having a first wavelength and an optical pulse having a second wavelength. The measuring apparatus 500 includes a plurality of wavelength demultiplexers that demultiplex a plurality of wavelengths of light included in a plurality of backscattered light between each of a plurality of optical multiplexers / demultiplexers and a plurality of photoelectric conversion units. Is different from the measuring apparatus 100 described in relation to FIGS. 1 to 4. Thereby, the optical pulse having the first wavelength and the optical pulse having the second wavelength are alternately output, and a plurality of measurements can be performed. As a result, the time required to measure all the optical fiber core wires is shorter than when the measuring apparatus 100 is used. The measuring apparatus 500 may have the same configuration as the measuring apparatus 100 with respect to points other than the above differences.

  In the present embodiment, the measurement apparatus 500 includes an optical pulse output unit 510, a plurality of optical multiplexers / demultiplexers including an optical multiplexer / demultiplexer 112, an optical multiplexer / demultiplexer 114, and an optical multiplexer / demultiplexer 116, and a measurement unit 520. . The measurement unit 520 includes a light receiving unit 542, a plurality of wavelength demultiplexers including a wavelength demultiplexer 552, a wavelength demultiplexer 554, and a wavelength demultiplexer 556, a signal processing unit 144, and a control unit 146. The measurement unit 520 may include an input unit 162 and a notification unit 164. The plurality of wavelength demultiplexers are provided corresponding to each of the plurality of optical fiber core wires. Each of the plurality of wavelength demultiplexers may be an example of an optical demultiplexing unit.

  In the present embodiment, the optical pulse output unit 510 alternates between the first optical pulse having the first wavelength and the second optical pulse having the second wavelength at each of the incident ends of the plurality of optical fiber core wires. Is incident on. Each of the wavelength demultiplexer 552, the wavelength demultiplexer 554, and the wavelength demultiplexer 556 is provided corresponding to the optical fiber core line 12, the optical fiber core line 14, and the optical fiber core line 16, respectively. Each of the wavelength demultiplexer 552, the wavelength demultiplexer 554, and the wavelength demultiplexer 556 is backscattered light from the corresponding optical fiber core line, and corresponds to each of the first optical pulse and the second optical pulse. Then, the backscattered light from a plurality of positions having different distances from the incident end is demultiplexed into light having the first wavelength and light having the second wavelength.

  FIG. 6 schematically shows an example of the light receiving unit 542. In the present embodiment, the light receiving unit 542 includes a plurality of first photoelectric conversion units including a first photoelectric conversion unit 652, a first photoelectric conversion unit 654, and a first photoelectric conversion unit 656, and a second photoelectric conversion. A plurality of second photoelectric conversion units including a unit 662, a second photoelectric conversion unit 664, and a second photoelectric conversion unit 666. Each of the plurality of first photoelectric conversion units is provided corresponding to each of the plurality of optical demultiplexing units. Each of the plurality of second photoelectric conversion units is provided corresponding to each of the plurality of optical demultiplexing units.

  The first photoelectric conversion unit 652, the first photoelectric conversion unit 654, and the first photoelectric conversion unit 656 correspond to the wavelength demultiplexer 552, the wavelength demultiplexer 554, and the wavelength demultiplexer 556, respectively. Provided. Each of the first photoelectric conversion unit 652, the first photoelectric conversion unit 654, and the first photoelectric conversion unit 656 converts light having the first wavelength demultiplexed by the corresponding wavelength demultiplexer into an electric signal. To do. Each of the first photoelectric conversion unit 652, the first photoelectric conversion unit 654, and the first photoelectric conversion unit 656 transmits an electrical signal obtained by converting the backscattered light to the signal processing unit 144.

  Each of the second photoelectric conversion unit 662, the second photoelectric conversion unit 664, and the second photoelectric conversion unit 666 corresponds to the wavelength demultiplexer 552, the wavelength demultiplexer 554, and the wavelength demultiplexer 556, respectively. Provided. Each of the second photoelectric conversion unit 662, the second photoelectric conversion unit 664, and the second photoelectric conversion unit 666 converts light having the second wavelength demultiplexed by the corresponding wavelength demultiplexer into an electric signal. To do. Each of the second photoelectric conversion unit 662, the second photoelectric conversion unit 664, and the second photoelectric conversion unit 666 transmits an electrical signal obtained by converting the backscattered light to the signal processing unit 144.

  FIG. 7 schematically shows an example of the optical pulse output unit 510. In the present embodiment, the optical pulse output unit 510 includes a light source 712, a light source 714, a wavelength multiplexer 720, an optical splitter 220, a pulse generator 230, and a delay 730. The light source 712 and the light source 714 may be an example of a first light source and a second light source, respectively. The wavelength multiplexer 720 may be an example of an optical multiplexer.

  In the present embodiment, the optical pulse output unit 510 outputs an optical pulse having the first wavelength almost simultaneously to all of the plurality of optical fiber core wires to be tested. The optical pulse output unit 510 outputs an optical pulse having the second wavelength almost simultaneously to all of the plurality of optical fiber core wires to be tested.

  The light source 712 generates light having a first wavelength. A pulse signal is input from the pulse generator 230 to the light source 712. The light source 714 generates light having the second wavelength. A pulse signal from the pulse generator 230 is input to the light source 714 via the delay unit 730. The wavelength multiplexer 720 receives light from the light source 712 and light from the light source 714. The wavelength combiner 720 combines the light from the light source 712 and the light from the light source 714 and outputs the combined light to the optical branching device 220.

  The delay device 730 is provided between the pulse generator 230 and the light source 714. The pulse signal from the pulse generator 230 is input to the delay unit 730. The delay device 730 delays the input pulse signal and outputs the delayed pulse signal to the light source 714. The delay device may be an example of a delay unit. Thereby, the optical pulse output unit 510 can alternately output the optical pulse having the first wavelength and the optical pulse having the second wavelength.

  FIG. 8 schematically shows an example of the optical pulse output unit 810. The optical pulse output unit 810 is the light described with reference to FIG. 7 in that the optical pulse is generated using an optical switch and the pulse signal is input from the pulse generator 230 to the light source 712 and the light source 714. Different from the pulse output unit 510. The optical pulse output unit 810 is different from the optical pulse output unit 310 in that light having a first wavelength and light having a second wavelength are input to the optical branching device 220.

  In the present embodiment, the optical pulse output unit 810 includes a light source 712, a light source 714, a wavelength multiplexer 720, an optical branching device 220, a pulse generator 230, a signal branching device 340, an optical switch 352, an optical switch. A plurality of optical switches including a switch 354 and an optical switch 356. In the present embodiment, light from the wavelength multiplexer 720 is input to the input terminals of the optical switch 352, the optical switch 354, and the optical switch 356 via the optical splitter 220. The optical switch 352, the optical switch 354, and the optical switch 356 switch the connection state between the input terminal and the output terminal based on the pulse signal input to the drive terminal, so that the first optical pulse and the second optical pulse are switched. And are output alternately.

  Thereby, the optical pulse output unit 810 outputs an optical pulse having the first wavelength almost simultaneously to all of the plurality of optical fiber core wires to be tested. The optical pulse output unit 810 outputs an optical pulse having the second wavelength almost simultaneously to all of the plurality of optical fiber core wires to be tested.

  FIG. 9 schematically shows an example of the optical pulse output unit 910. The optical pulse output unit 910 generates an optical pulse using an optical switch having a plurality of output terminals with respect to two input terminals, and the optical pulse output unit 410 described with reference to FIG. 8 is different from the optical pulse output unit 810 described in connection with FIG. A PLZT high-speed optical switch manufactured by Epiphotonics Co., Ltd. may be used as an optical switch having a plurality of output terminals for two input terminals.

  In this embodiment, the optical pulse output unit 910 includes a light source 712, a light source 714, a pulse generator 230, a signal branching unit 340, an optical switch 950, a delay unit 462, a delay unit 464, and a delay unit 466. A plurality of first delay devices and a plurality of second delay devices including a delay device 962, a delay device 964, and a delay device 966 are provided. In the present embodiment, the signal branching unit 340 branches the input pulse signal and outputs the branched pulse signal to each of the plurality of first delay units and each of the plurality of second delay units.

  The optical switch 950 is different from the optical switch 450 in that it has a plurality of output terminals for two input terminals. The optical switch 950 includes an input terminal IT1, an input terminal IT2, a plurality of output terminals including an output terminal OT1, an output terminal OT2, and an output terminal OTN, and a plurality of first terminals including a drive terminal DT11, a drive terminal DT12, and a drive terminal DT1N. And a plurality of second drive terminals including the drive terminal DT21, the drive terminal DT22, and the drive terminal DT2N. Each of the plurality of first drive terminals is provided corresponding to each of the input terminal IT1 and the plurality of output terminals. Each of the plurality of second drive terminals is provided corresponding to each of the input terminal IT2 and the plurality of output terminals.

  Each of the plurality of first delay devices is provided corresponding to each of the plurality of first drive terminals. Each of the plurality of first delay devices is provided between the pulse generator 230 and each of the plurality of first drive terminals. A pulse signal from the pulse generator 230 is input to each of the plurality of first delay units via the signal branching unit 340. Each of the plurality of first delay devices delays the input pulse signal and outputs it to the corresponding first drive terminal. The amount of delay in each of the plurality of first delay units may be determined by the control unit 146. The first delay unit may be an example of a first delay unit.

  Each of the plurality of second delay devices is provided corresponding to each of the plurality of second drive terminals. Each of the plurality of second delay devices is provided between the pulse generator 230 and each of the plurality of second drive terminals. A pulse signal from the pulse generator 230 is input to each of the plurality of second delay devices via the signal branching unit 340. Each of the plurality of second delay devices delays the input pulse signal and outputs it to the corresponding second drive terminal. The amount of delay in each of the plurality of second delay devices may be determined by the control unit 146. The second delay device may be an example of a second delay unit.

  The controller 146 is based on the number of optical fiber core wires, the period of the first optical pulse and the period of the second optical pulse, and the pulse width of the first optical pulse and the pulse width of the second optical pulse. Thus, the delay amount in each of the plurality of first delay units may be determined. The controller 146 is based on the number of optical fiber core wires, the period of the first optical pulse and the period of the second optical pulse, and the pulse width of the first optical pulse and the pulse width of the second optical pulse. Thus, the delay amount in each of the plurality of second delay units may be determined.

  The optical switch 950 switches whether or not light from at least one of the light source 712 and the light source 714 enters each of the plurality of optical fiber core wires. Light from the light source 712 is input to the terminal IT1. Light from the light source 714 is input to the input terminal IT2. Each of the plurality of output terminals outputs light from one of the input terminal IT1 and the input terminal IT2 to the corresponding optical fiber core wire when connected to one of the input terminal IT1 and the input terminal IT2.

  The drive terminal DT11, the drive terminal DT12, and the drive terminal DT1N are provided corresponding to the input terminal IT1, the output terminal OT1, the output terminal OT2, and the output terminal OTN, respectively. The pulse signal from the pulse generator 230 is input to each of the drive terminal DT11, the drive terminal DT12, and the drive terminal DT1N via the delay unit 462, the delay unit 464, and the delay unit 466, respectively.

  The drive terminal DT21, the drive terminal DT22, and the drive terminal DT2N are provided corresponding to the input terminal IT2, the output terminal OT1, the output terminal OT2, and the output terminal OTN, respectively. A pulse signal from the pulse generator 230 is input to each of the drive terminal DT21, the drive terminal DT22, and the drive terminal DT2N via each of the delay device 962, the delay device 964, and the delay device 966.

  The optical switch 950 switches the connection state between the input terminal DT1 and the output terminal corresponding to each of the plurality of first drive terminals based on the pulse signal input to each of the plurality of first drive terminals. The optical switch 950 switches the connection state between the input terminal DT2 and the output terminal corresponding to each of the plurality of second drive terminals based on the pulse signal input to each of the plurality of second drive terminals.

  Thereby, the optical switch 950 can output an optical pulse having the first wavelength and an optical pulse having the second wavelength. The optical switch 950 may output the optical pulse having the first wavelength and the optical pulse having the second wavelength at the same time, or may output the optical pulses at different timings.

  In one embodiment, the optical pulse output unit 910 sequentially outputs optical pulses so that the timings at which optical pulses are incident on a plurality of optical fiber core wires to be tested do not overlap each other. In another embodiment, the optical pulse output unit 910 sequentially outputs the optical pulses so that the timings at which the optical pulses are incident on a part of the optical fiber cores among a plurality of optical fiber cores to be tested overlap. To do. More specifically, the timing at which an optical pulse having a first wavelength is incident on a specific one optical fiber core line, and the optical pulse having a second wavelength on another optical fiber core line The light pulses are sequentially output so that the timings at which the light enters are overlapped.

  For example, when a pulse signal input to the drive terminal DT11 is H logic and a pulse signal input to the other first drive terminal is L logic at a specific timing, the optical switch 950 includes the input terminal IT1. Are connected to the output terminal OT1, and the light input to the input terminal IT1 is output from the output terminal OT1. At this time, when the pulse signal input to the drive terminal DT2N is H logic and the pulse signals input to the other second drive terminals are L logic, the optical switch 950 includes the input terminal IT2 and The output terminal OTN is connected, and the light input to the input terminal IT2 is output from the output terminal OTN. Thereby, the measuring apparatus 500 can enter the optical pulse having the first wavelength into the optical fiber core line 12 and the optical pulse having the second wavelength into the optical fiber core line 16.

  At the next timing, the pulse signal input to the drive terminal DT12 is H logic, and the pulse signals input to the other first drive terminals are L logic. At this time, the pulse signal input to the drive terminal DT21 is H logic, and the pulse signals input to the other second drive terminals are L logic. As a result, the measuring apparatus 500 makes the optical pulse having the first wavelength incident on the optical fiber core wire 14 and makes the optical pulse having the second wavelength incident on the optical fiber core wire 12. As described above, the measuring apparatus 500 controls the delay amounts in the first delay device and the second delay device, and thereby, with respect to some of the optical fiber core wires to be tested, The light pulses can be sequentially output so that the timings at which the light pulses are incident overlap.

The timing at which an optical pulse having the first wavelength is incident on one specific optical fiber core line overlaps with the timing at which an optical pulse having the second wavelength is incident on another optical fiber core line Thus, by sequentially outputting the optical pulses, the time required for measuring all the optical fiber core wires can be shortened. Further, it is possible to overlap at least a part of the timing in which a plurality of optical pulses having different wavelengths is output, it is possible to increase the time interval t _P. Therefore, the pulse width tw of the optical pulse can be increased. As a result, the peak light power of the light pulse can be reduced.

  In the present embodiment, the case where the optical pulse output unit 910 generates an optical pulse using an optical switch having a plurality of output terminals for two input terminals has been described. However, the optical pulse output unit 910 is not limited to this embodiment. The optical pulse output unit 910 may generate an optical pulse using an optical switch having a plurality of output terminals for four input terminals. In this case, the light from the light source 712 may be branched and input to the two input terminals, and the light from the light source 714 may be branched and input to the other two input terminals. Thereby, the time required for the measurement of all the optical fiber core wires can be further shortened.

  In the present embodiment, the case where the optical pulse output unit 910 generates an optical pulse using a single optical switch has been described. However, the optical pulse output unit 910 is not limited to this embodiment. The optical pulse output unit 910 may generate an optical pulse using a plurality of optical switches. In this case, the light from the light source 712 may be branched and input to the plurality of optical switches, and the light from the light source 714 may be branched and input to the plurality of optical switches. Thereby, the time required for the measurement of all the optical fiber core wires can be further shortened.

The execution order of each process such as operation, procedure, step, and stage in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the specification, and the drawings, even if it is described using “first”, “next”, etc. for the sake of convenience, it means that it is essential to carry out in this order. It is not a thing.
[Item 1]
An optical pulse output unit for inputting an optical pulse to each of incident ends of the plurality of optical fiber core wires; and
Back scattered light from each of the plurality of optical fiber cores corresponding to the light pulse incident on each of the plurality of optical fiber cores, and back scattered light from a plurality of positions having different distances from the incident end A measurement unit for measuring the optical power of
With
The measurement unit has a light receiving unit that receives backscattered light from each of the plurality of optical fiber core wires,
The light receiving unit is provided corresponding to each of the plurality of optical fiber cores, and has a plurality of photoelectric conversion units that convert backscattered light from the corresponding optical fiber cores into electric signals.
measuring device.
[Item 2]
The optical pulse output unit is
A light source that generates light;
A plurality of optical switches that are provided corresponding to each of the plurality of optical fiber core wires, and that switch whether or not light from the light source is incident on the corresponding optical fiber core wires;
A drive signal generator for generating a drive signal for driving each of the plurality of optical switches;
Have
Each of the plurality of optical switches
An input terminal for receiving light from the light source;
When connected to the input terminal, an output terminal that outputs light input to the input terminal to a corresponding optical fiber core; and
A drive terminal to which the drive signal is input;
Including
Based on the drive signal input to the drive terminal, the optical pulse is output by switching the connection state between the input terminal and the output terminal.
Item 1. The measuring device according to Item 1.
[Item 3]
The optical pulse output unit is
A light source that generates light;
An optical switch for switching whether or not light from the light source is incident on each of the plurality of optical fiber cores;
A drive signal generator for generating a drive signal for driving the optical switch;
Have
The optical switch
An input terminal for receiving light from the light source;
A plurality of output terminals that are provided corresponding to each of the plurality of optical fiber core wires and output to the corresponding optical fiber core wires when light is input to the input terminals when connected to the input terminals;
A plurality of drive terminals provided corresponding to each of the plurality of output terminals and receiving the drive signal;
Including
Based on the drive signal input to each of the plurality of drive terminals, the optical pulse is output by switching the connection state between the input terminal and an output terminal corresponding to each of the plurality of drive terminals. ,
Item 1. The measuring device according to Item 1.
[Item 4]
A control unit for controlling the optical pulse output unit;
The optical pulse output unit is
Corresponding to each of the plurality of drive terminals, a plurality of delay units provided between the drive signal generation unit and each of the plurality of drive terminals and delaying the drive signal received from the drive signal generation unit Have
The control unit determines a delay amount in each of the plurality of delay units based on the number of the plurality of optical fiber core wires, the period of the optical pulse, and the pulse width of the optical pulse,
Item 4. The measuring device according to Item 3.
[Item 5]
The measurement unit further includes a plurality of optical demultiplexing units provided corresponding to each of the plurality of optical fiber core wires,
The optical pulse output unit alternately enters a first optical pulse having a first wavelength and a second optical pulse having a second wavelength at each of incident ends of the plurality of optical fiber core wires,
Each of the plurality of optical demultiplexing units is backscattered light from a corresponding optical fiber core line, corresponds to each of the first optical pulse and the second optical pulse, and is a distance from the incident end. Are demultiplexed into light having the first wavelength and light having the second wavelength, and
The light receiving unit is
A plurality of first photoelectric conversion units provided corresponding to each of the plurality of optical demultiplexing units and converting the light having the first wavelength demultiplexed by the corresponding optical demultiplexing unit into an electrical signal; ,
A plurality of second photoelectric conversion units provided corresponding to each of the plurality of optical demultiplexing units, and converting the light having the second wavelength demultiplexed by the corresponding optical demultiplexing unit into an electric signal; ,
including,
Item 1. The measuring device according to Item 1.
[Item 6]
The optical pulse output unit is
A first light source for generating light having the first wavelength;
A second light source for generating light having the second wavelength;
An optical multiplexing unit for multiplexing the light from the first light source and the light from the second light source;
A plurality of optical switches that are provided corresponding to each of the plurality of optical fiber core wires, and that switch whether or not light from the optical multiplexing unit is incident on the corresponding optical fiber core wires;
A drive signal generator for generating a drive signal for controlling the operation of each of the plurality of optical switches;
Have
Each of the plurality of optical switches
An input terminal to which light from the optical multiplexing unit is input;
When connected to the input terminal, an output terminal that outputs light input to the input terminal to a corresponding optical fiber core; and
A drive terminal to which the drive signal is input;
Including
The first optical pulse and the second optical pulse are alternately output by switching the connection state between the input terminal and the output terminal based on the drive signal input to the drive terminal.
Item 6. The measuring device according to Item 5.
[Item 7]
The optical pulse output unit is
A first light source for generating light having the first wavelength;
A second light source for generating light having the second wavelength;
An optical switch for switching whether or not light from at least one of the first light source and the second light source is incident on each of the plurality of optical fiber cores;
A drive signal generator for generating a drive signal for driving the optical switch;
Have
The optical switch
A first input terminal to which light from the first light source is input;
A second input terminal to which light from the second light source is input;
The first input terminal and the second input terminal provided corresponding to each of the plurality of optical fiber core wires and connected to one of the first input terminal and the second input terminal. A plurality of output terminals for outputting light from one of the optical fiber core wires,
A plurality of first drive terminals provided corresponding to each of the first input terminal and the plurality of output terminals, to which the drive signal is input;
A plurality of second drive terminals provided corresponding to each of the second input terminal and the plurality of output terminals, to which the drive signal is input;
Including
Based on the drive signal input to each of the plurality of first drive terminals, the connection state between the first input terminal and the output terminal corresponding to each of the plurality of first drive terminals is switched. The connection state between the second input terminal and an output terminal corresponding to each of the plurality of second drive terminals is determined based on the drive signal input to each of the plurality of second drive terminals. By switching, the first light pulse and the second light pulse are alternately output.
Item 6. The measuring device according to Item 5.
[Item 8]
A control unit for controlling the optical pulse output unit;
The optical pulse output unit is
Corresponding to each of the plurality of first drive terminals, the drive signal received from the drive signal generation unit is provided between the drive signal generation unit and each of the plurality of first drive terminals. A plurality of first delay units for delaying;
Corresponding to each of the plurality of second drive terminals, the drive signal received from the drive signal generation unit is provided between the drive signal generation unit and each of the plurality of second drive terminals. A plurality of second delay units for delaying;
Have
The control unit includes the number of the plurality of optical fiber core wires, the period of the first optical pulse, the period of the second optical pulse, the pulse width of the first optical pulse, and the second optical pulse. A delay amount in each of the plurality of first delay units and the plurality of second delay units is determined based on the pulse width of
Item 8. The measuring device according to Item 7.
[Item 9]
The control unit
Based on at least one of the number of types of wavelengths of the optical pulse, the number of optical fiber core wires, the pulse width of the optical pulse, the period of the optical pulse, and the operation mode of the optical switch, Determining the maximum value of at least one of the number of fiber cores and the pulse width of the optical pulse;
Item 9. The measuring device according to Item 8.

  12 optical fiber core wire, 14 optical fiber core wire, 16 optical fiber core wire, 100 measuring device, 110 optical pulse output unit, 112 optical multiplexer / demultiplexer, 114 optical multiplexer / demultiplexer, 116 optical multiplexer / demultiplexer, 120 measuring unit, 142 light receiving unit 144 signal processing unit, 146 control unit, 152 photoelectric conversion unit, 154 photoelectric conversion unit, 156 photoelectric conversion unit, 162 input unit, 164 notification unit, 210 light source, 220 optical branching unit, 230 pulse generator, 310 optical pulse output Unit, 340 signal branching unit, 352 optical switch, 354 optical switch, 356 optical switch, 410 optical pulse output unit, 450 optical switch, 462 delay unit, 464 delay unit, 466 delay unit, 500 measuring device, 510 optical pulse output unit 520 measuring unit, 542 light receiving unit, 552 wavelength demultiplexer, 554 wavelength demultiplexer 556 Wavelength demultiplexer, 652 Photoelectric conversion unit, 654 Photoelectric conversion unit, 656 Photoelectric conversion unit, 662 Photoelectric conversion unit, 664 Photoelectric conversion unit, 666 Photoelectric conversion unit, 712 Light source, 714 Light source, 720 Wavelength combiner, 730 Delay Unit, 810 optical pulse output unit, 910 optical pulse output unit, 950 optical switch, 962 delay unit, 964 delay unit, 966 delay unit

Claims (5)

An optical pulse output unit for inputting an optical pulse to each of incident ends of the plurality of optical fiber core wires; and
Back scattered light from each of the plurality of optical fiber core wires corresponding to light pulses incident on each of the plurality of optical fiber core wires, and from a plurality of positions having different distances from the incident end. A measurement unit for measuring the optical power of
With
The measuring unit is
A light receiving unit that receives backscattered light from each of the plurality of optical fiber cores ;
A plurality of optical demultiplexing units provided corresponding to each of the plurality of optical fiber cores;
Have
The optical pulse output unit alternately enters a first optical pulse having a first wavelength and a second optical pulse having a second wavelength at each of incident ends of the plurality of optical fiber core wires,
Each of the plurality of optical demultiplexing units is backscattered light from a corresponding optical fiber core line, corresponds to each of the first optical pulse and the second optical pulse, and is a distance from the incident end. Demultiplexing backscattered light from a plurality of different positions into light having the first wavelength and light having the second wavelength,
The light receiving portion is provided corresponding to each of the plurality of optical fiber core, for converting the backscattered light from the corresponding optical fiber core into an electric signal, have a plurality of photoelectric conversion portions,
The plurality of photoelectric conversion units are
A plurality of first photoelectric conversion units provided corresponding to each of the plurality of optical demultiplexing units, and converting light having the first wavelength demultiplexed by the corresponding optical demultiplexing unit into an electric signal; ,
A plurality of second photoelectric conversion units that are provided corresponding to each of the plurality of optical demultiplexing units and that convert the light having the second wavelength demultiplexed by the corresponding optical demultiplexing units into an electrical signal; ,
including,
measuring device. The optical pulse output unit is
A first light source for generating light having the first wavelength;
A second light source for generating light having the second wavelength;
An optical multiplexing unit for multiplexing the light from the first light source and the light from the second light source;
A plurality of optical switches that are provided corresponding to each of the plurality of optical fiber core wires, and that switch whether or not light from the optical multiplexing unit is incident on the corresponding optical fiber core wires;
A drive signal generator for generating a drive signal for controlling the operation of each of the plurality of optical switches;
Have
Each of the plurality of optical switches is
An input terminal to which light from the optical multiplexing unit is input;
When connected to the input terminal, an output terminal that outputs light input to the input terminal to a corresponding optical fiber core; and
A drive terminal to which the drive signal is input;
Including
Based on the drive signal input to the drive terminal, the first optical pulse and the second optical pulse are alternately output by switching the connection state between the input terminal and the output terminal.
The measuring apparatus according to claim 1 . The optical pulse output unit is
A first light source for generating light having the first wavelength;
A second light source for generating light having the second wavelength;
An optical switch for switching whether or not light from at least one of the first light source and the second light source is incident on each of the plurality of optical fiber cores;
A drive signal generator for generating a drive signal for driving the optical switch;
Have
The optical switch is
A first input terminal to which light from the first light source is input;
A second input terminal to which light from the second light source is input;
The first input terminal and the second input terminal provided corresponding to each of the plurality of optical fiber core wires and connected to one of the first input terminal and the second input terminal. A plurality of output terminals for outputting light from one of the optical fiber core wires,
A plurality of first drive terminals provided corresponding to each of the first input terminal and the plurality of output terminals, to which the drive signal is input;
A plurality of second drive terminals provided corresponding to each of the second input terminal and the plurality of output terminals, to which the drive signal is input;
Including
Based on the drive signal input to each of the plurality of first drive terminals, the connection state of the first input terminal and the output terminal corresponding to each of the plurality of first drive terminals is switched. The connection state between the second input terminal and the output terminal corresponding to each of the plurality of second drive terminals is determined based on the drive signal input to each of the plurality of second drive terminals. By switching, the first light pulse and the second light pulse are alternately output,
The measuring apparatus according to claim 1 . A control unit for controlling the optical pulse output unit;
The optical pulse output unit is
Corresponding to each of the plurality of first drive terminals, the drive signal received from the drive signal generation unit is provided between the drive signal generation unit and each of the plurality of first drive terminals. A plurality of first delay units for delaying;
Corresponding to each of the plurality of second drive terminals, the drive signal received from the drive signal generation unit is provided between the drive signal generation unit and each of the plurality of second drive terminals. A plurality of second delay units for delaying;
Have
The control unit includes the number of the plurality of optical fiber core wires, the period of the first optical pulse and the period of the second optical pulse, the pulse width of the first optical pulse, and the second optical pulse. A delay amount in each of the plurality of first delay units and the plurality of second delay units is determined based on the pulse width of
The measuring apparatus according to claim 3 . The controller is
Based on at least one of the number of types of wavelengths of the optical pulse, the number of optical fiber core wires, the pulse width of the optical pulse, the period of the optical pulse, and the operation mode of the optical switch, Determining the maximum value of at least one of the number of fiber cores and the pulse width of the optical pulse;
The measuring apparatus according to claim 4 .