JP2012127693A - Distance measuring equipment, optical multiplexer, optical network, and distance measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide distance measuring equipment capable of specifying a failure position or the like in an optical fiber without using an exclusive tester (OTDR), and to provide an optical multiplexer, an optical network and a distance measuring method.SOLUTION: The distance measuring equipment includes: an AD wavelength light selection switch 50 capable of transmitting a pulse-like optical signal to a measuring optical fiber by switching an output to the measuring optical fiber only for predetermined time by using inputted light; a directional coupler 60 for branching return light returned by reflecting or scattering the optical signal transmitted from the AD wavelength light selection switch 50 on a position to be inspected within the measuring optical fiber from the measuring optical fiber; and an optical receiver 70 for receiving the return light branched by the directional coupler 60. A distance from the optical receiver 70 or the like up to the position to be inspected is measured by time required from the transmission of the optical signal from the AD wavelength light selection switch 50 up to the reception of the return light by the optical receiver 70.

Description

  The present invention relates to a distance measuring device, an optical multiplexing device, an optical network, and a distance measuring method for measuring a distance from a measurement position to an inspection target position in order to specify an inspection target position (failure location or the like) in an optical fiber. Is.

In recent years, in an optical network, a ROADM (Reconfigurable Optical Add / Drop Multiplexer (Reconfigurable Optical Add / Drop Multiplexer) that can perform signal processing without converting an optical signal into an electrical signal and can remotely control a path setting. Drop Multiplexer)) and the like have been developed (see Patent Document 1).

  In general, in order to specify a position to be inspected in an optical fiber, an OTDR (Optical Time Domain (Optical Time Domain) composed of a light source that emits an optical pulse, a detector that detects backscattered light due to Rayleigh scattering, and the like. Reflectmeter)) is used (see Patent Document 2). As described above, also in an optical network using an optical multiplexing device, it is possible to specify an inspection target position such as a failure location in an optical fiber constituting the optical network using OTDR.

JP 2010-98545 A JP 11-142293 A

  As described above, by using a dedicated tester (OTDR) for examining a failure location or the like, a position to be inspected such as a failure location in the optical fiber can be specified.

  However, the inventor of the present application pays attention to the function of the optical multiplexing device (more specifically, the function of the device provided in the optical multiplexing device), and skillfully uses the function, so that a dedicated tester can be used. Even without using it, the position of the inspection object in the optical fiber can be specified.

  An object of the present invention is to provide a distance measuring device, an optical multiplexing device, an optical network, and a distance measuring method that can identify a failure location in an optical fiber without using a dedicated tester (OTDR). is there.

  The present invention employs the following means in order to solve the above problems.

That is, the distance measuring device of the present invention is
By switching the output to the measurement optical fiber among the plurality of optical fibers connected to the output side for a predetermined time using the input light, a pulsed optical signal (for example, about 20 ms) is supplied to the measurement optical fiber. An optical switch capable of transmitting an optical pulse signal (for example, a MEMS optical switch or a waveguide optical switch);
The optical signal transmitted from the optical switch is reflected (for example, reflected from the connection point of the optical fiber) or scattered (for example, scattered at the failure point) at the inspection target position in the measurement optical fiber. A directional coupler (such as a directional coupling coupler) for branching the returning light from the measurement optical fiber;
An optical receiver for receiving the return light branched by the directional coupler;
With
Measuring the distance from the optical switch or the optical receiver to the position to be inspected according to the time from when the optical signal is transmitted from the optical switch to when the return light is received by the optical receiver. Features.

Further, the distance measuring device of another invention uses the input light to switch the output to the measuring optical fiber connected to the output side from the cut-off state to the passing state for a predetermined time. An optical breaker capable of transmitting a pulsed optical signal (for example, an optical pulse signal of about 20 ms);
The optical signal transmitted from the optical breaker is reflected (for example, reflected from the connection point of the optical fiber) or scattered (for example, scattered at the failure point) at the inspection target position in the measurement optical fiber. A directional coupler (such as a directional coupling coupler) for branching the returning light from the measurement optical fiber;
An optical receiver for receiving the return light branched by the directional coupler;
With
Measuring the distance from the optical interrupter or the optical receiver to the inspection target position according to the time from when the optical signal is transmitted from the optical interrupter to when the return light is received by the optical receiver. Features.

According to still another aspect of the invention, the distance measuring device uses the input light to release the output to the measuring optical fiber connected to the output side from the cut-off state for a predetermined time. An optical attenuator capable of transmitting an optical signal (for example, an optical pulse signal of about 20 ms);
The optical signal transmitted from the optical attenuator is reflected back (for example, reflected from the connection point of the optical fiber) or scattered (for example, scattered at the failure point) at the inspection target position in the measurement optical fiber. A directional coupler (such as a directional coupling coupler) for branching the returning light from the measurement optical fiber;
An optical receiver for receiving the return light branched by the directional coupler;
With
Measuring a distance from the optical attenuator or the optical receiver to the position to be inspected according to a time from when an optical signal is transmitted from the optical attenuator to when the return light is received by the optical receiver. Features.

  In these inventions, by using an optical switch, optical breaker or optical attenuator (hereinafter referred to as “optical switch etc.” as appropriate), a pulsed optical signal is transmitted to the measurement optical fiber. A configuration is adopted in which the distance from the optical switch or the like or the optical receiver to the position to be inspected is measured. Thereby, the inspection target position can be specified. Therefore, in a network or the like provided with “an optical switch or the like capable of transmitting a pulsed optical signal to a measurement optical fiber”, by adopting the configuration of the present invention, a dedicated tester (OTDR) is not used. It is possible to specify the inspection target position (failure location, etc.) in the optical fiber.

  The optical switch or the like may be an optical switch or the like that is capable of transmitting a pulsed optical signal to the measurement optical fiber using input light having a plurality of different wavelengths.

  Thereby, it is possible to specify the inspection target position on the path through which light of a specific wavelength passes.

  The optical switch or the like can be incident on the measurement fiber of the plurality of optical fibers connected to the output side by reflecting the input optical signal with a micro mirror whose inclination position is changed by on / off control. A good DMD.

  As a result, even if the optical signal input to the optical switch or the like is continuous light, a pulsed optical signal can be transmitted by switching the direction of reflected light from the micromirror by on / off control to the DMD. .

Further, the measurement optical fiber is an optical fiber constituting a backbone network,
In an optical multiplexing device including an add optical switch capable of adding light of an arbitrary wavelength to the measurement optical fiber,
The add optical switch is used as the optical switch in the distance measuring apparatus.

  In this way, when an optical multiplexing device is connected to the measurement optical fiber, a pulsed optical signal is generated by the add optical switch provided in the optical multiplexing device, so that the inspection target position is Can be specified. The light to be input to the add optical switch may use light transmitted from a transponder in an optical multiplexing device including the add optical switch, or a transponder in another optical multiplexing device. The light transmitted from the light source may be used, or light from a light source other than the optical multiplexing device may be used.

  Here, the add optical switch includes the directional coupler and the optical receiver in the distance measuring device in the optical multiplexing device used as the optical switch in the distance measuring device. Good.

  In this way, since the optical switch for transmitting a pulsed optical signal and the optical receiver are provided in one multiplexer, the optical receiver after the optical signal is transmitted from the optical switch. Therefore, the time until reception can be measured with a simple configuration.

The optical network of the present invention
A backbone network composed of measurement optical fibers;
A plurality of optical multiplexing devices provided on the backbone network;
A plurality of local networks respectively connected to each optical multiplexer;
In an optical network comprising:
An add optical switch provided in at least one of the plurality of optical multiplexers is used as the optical switch in the distance measuring apparatus.

  Thereby, it is possible to specify the inspection target position in the optical fiber constituting the backbone network without using a dedicated tester (OTDR).

The distance measuring method of the present invention is
Optical switching that can transmit a pulsed optical signal to the measurement optical fiber by switching the output to the measurement optical fiber among a plurality of optical fibers connected to the output side for a predetermined time using the input light And
A directional coupler for branching from the measurement optical fiber return light that is returned when the optical signal transmitted from the optical switch is reflected or scattered at the inspection target position in the measurement optical fiber;
An optical receiver for receiving the return light branched by the directional coupler;
Use
Transmitting a pulsed optical signal from the optical switch to the measurement optical fiber;
Receiving the return light returned from the inspection target position in the optical fiber by being branched by the directional coupler by the optical receiver;
Deriving a distance from the optical switch or the optical receiver to the inspection target position according to a time from when an optical signal is transmitted from the optical switch to when the return light is received by the optical receiver; ,
It is characterized by having.

  In addition, said each structure can be employ | adopted combining as much as possible.

  As described above, according to the present invention, it is possible to specify a position to be inspected such as a failure location in an optical fiber without using a dedicated tester (OTDR).

FIG. 1 is a schematic configuration diagram of an optical network using an optical multiplexing device. FIG. 2 is a block diagram of the optical multiplexing apparatus according to the first embodiment of the present invention. FIG. 3 is a schematic configuration diagram of the wavelength selective switch. FIG. 4 is a block diagram of the distance measuring apparatus according to the first embodiment of the present invention. FIG. 5 is a block diagram showing an application example 1 of the distance measuring apparatus according to the first embodiment of the present invention. FIG. 6 is a block diagram showing an application example 2 of the distance measuring apparatus according to the first embodiment of the present invention. FIG. 7 is a schematic configuration diagram of a wavelength blocker (wavelength filter). FIG. 8 is a block diagram of a distance measuring apparatus according to the second embodiment of the present invention.

  DETAILED DESCRIPTION Exemplary embodiments for carrying out the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

(First embodiment)
A distance measuring device, an optical multiplexing device, an optical network, and a distance measuring method according to the first embodiment of the present invention will be described with reference to FIGS.

<Optical network>
In particular, an optical network to which the distance measuring apparatus according to the first embodiment of the present invention can be applied will be described with reference to FIG.

  In this optical network, an optical multiplexing device (ROADM) capable of both optical branching and optical insertion is installed at a plurality of locations of a backbone network N composed of ring-shaped optical fibers. In the example shown in FIG. 1, the case where the optical multiplexing apparatus is each installed in four places, A point, B point, C point, and D point is shown. Hereinafter, for convenience of explanation, the optical multiplexing devices arranged at points A, B, C, and D are appropriately selected from the first optical multiplexing device 100a, the second optical multiplexing device 100b, and the third optical multiplexing device, respectively. 100c and the fourth optical multiplexer 100d. The first optical multiplexing device 100a, the second optical multiplexing device 100b, the third optical multiplexing device 100c, and the fourth optical multiplexing device 100d include a local network for connecting a user and a network such as an office or a home. n1, n2, n3, and n4 are connected to each other.

ROADM, which is a typical example of an optical multiplexing apparatus, can extract an optical signal of an arbitrary wavelength from wavelength-multiplexed optical signals flowing through the backbone network N and send it to the local network n. It is also possible to send an optical signal having an arbitrary wavelength from the network n to the backbone network N. In FIG. 1, as an example, an optical signal having a certain wavelength is sent from the local network n1 to the backbone network N by the first optical multiplexing device 100a and sent to the local network n3 by the third optical multiplexing device 100c (in the drawing). , Arrow P1) and a case where an optical signal of another wavelength is sent from the local network n2 to the backbone network N by the second optical multiplexer 100b and sent to the local network n4 by the fourth optical multiplexer 100d (in the figure, Arrow P2) is shown. Note that an arrow S in the figure indicates the direction of the optical signal flow in the positive direction.

  Here, the optical multiplexing apparatus can perform signal processing without converting an optical signal into an electrical signal. Therefore, an optical network using an optical multiplexing device has an advantage that the transmission speed of the optical signal between the backbone network N and the local network n can be maintained at a high speed. Further, in an optical network using an optical multiplexing device, since the optical multiplexing device node can be remotely controlled from the operation center 200, there is an advantage that a path (light path of a certain wavelength) can be freely set.

<Optical multiplexer>
In particular, an optical multiplexing device (ROADM) 100 according to the first embodiment of the present invention will be described with reference to FIG.

  The optical multiplexer 100 includes an optical coupler 10 that branches an optical signal that flows through the backbone network N, a drop wavelength selective switch (WSS) 20 that drops an optical signal having a specific wavelength among the branched optical signals, and The first transponder 30 receives the dropped optical signal and outputs it to the local network n side. The optical multiplexing apparatus 100 receives the optical signal from the local network n side, blocks the second transponder 40 output to the backbone network N side, and the optical signal having the dropped wavelength, and outputs the second optical signal. An add wavelength selective switch (WSS) 50 that adds light of a specific wavelength to the backbone network N among optical signals transmitted from the transponder 40 is provided. In the drawing, the portion surrounded by a dotted line 100X indicates a configuration group included in a general ROADM.

  In the optical multiplexing apparatus 100 according to the present embodiment, in addition to the configuration provided in the general ROADM 100X, an optical signal that flows in the reverse direction (the direction opposite to the arrow S in FIGS. A directional coupler 60 for branching and an optical receiver 70 for receiving an optical signal branched by the directional coupler 60 are provided.

<Wavelength selective switch (WSS)>
The add wavelength selective switch 50 provided in the optical multiplexing apparatus 100 will be described. Since the wavelength selective switch itself is a known technique, only the outline will be described with reference to the schematic diagram of FIG. In the following description, the add wavelength selective switch 50 will be described. However, the drop wavelength selective switch 20 has the same configuration except that the light traveling direction is reversed. Further, the wavelength selective switch is also provided with optical components such as a lens for condensing light and a collimator lens for converting the diffusing light into parallel light, which are omitted in FIG. FIG. 3 shows a 1 × 2 wavelength selective switch. By repeating the connection of the 1 × 2 wavelength selective switch to the subsequent stage n times, a 1 × 2n wavelength selective switch can be configured.

  The add wavelength selective switch 50 includes a DMD (Digital Micromirror Device) 51, a fiber array 52 that couples the input fiber f1, the first output fiber f2, and the second output fiber f3, and an optical multiplexer / demultiplexer 53. ing.

The DMD 51 includes a plurality of movable micro mirrors. Hereinafter, for convenience of explanation, in FIG.
From the top, the first micromirror 51a, the second micromirror 51b, the third micromirror 51c, the fourth micromirror 51d, the fifth micromirror 51e, and the sixth micromirror 51f will be described as appropriate. Each of these micromirrors is configured to take two tilt positions by on / off control.

  The optical multiplexer / demultiplexer 53 demultiplexes the multiplexed optical signals having different wavelengths into the optical signals of the respective wavelengths, and multiplexes the optical signals having different wavelengths. And AWG (Arrayed Waveguide Grating).

  With the above configuration, a plurality of multiplexed optical signals having different wavelengths input from the input fiber f1 to the optical multiplexer / demultiplexer 53 are demultiplexed into optical signals of the respective wavelengths. In the example shown in FIG. 3, the optical signals of six types of wavelengths are demultiplexed, and the optical signals of each wavelength are respectively the first micromirror 51a, the second micromirror 51b, the third micromirror 51c, and the fourth micromirror 51d. , Are incident on the fifth micro mirror 51e and the sixth micro mirror 51f. For example, each micromirror reflects incident light so as to be guided to the H portion of the optical multiplexer / demultiplexer 53 when turned on, and reflects the incident light when combined with the optical multiplexer / demultiplexer. It is configured to reflect so as to be guided to the I part of 53. In the example shown in FIG. 3, by turning off only the second micromirror 51b and turning on the other micromirrors, the reflected light from the second micromirror 51b is guided to the second output fiber f3, and from the other micromirrors. In this case, the reflected light is guided to the first output fiber f2 in a state of being multiplexed by the optical multiplexer / demultiplexer 53.

  As described above, the wavelength selective switch (WSS) guides an optical signal having an arbitrary wavelength from the multiplexed optical signals having different wavelengths to the first output fiber f2, and transmits the optical signals having the remaining wavelengths. It can be led to a two-output fiber f3.

  An example of a wavelength selective switch is disclosed in US Patent Publication US2009 / 0028501A1. In the wavelength selective switch disclosed in this publication, a configuration in which reflected light from the DMD is also guided with respect to a collimator lens for entering the DMD in a state where the demultiplexed optical signal is converted into parallel light. Is disclosed.

<Distance measuring device>
In particular, a distance measuring apparatus according to the first embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram showing a main configuration related to distance measurement.

  As described above, in the optical multiplexing apparatus 100, an optical signal from the local network n side is sent to the add wavelength selective switch 50 via the second transponder 40 (in FIG. 2 and FIG. 4, arrows). T10). When distance measurement is performed, the controller 82 controls the DMD 51 provided in the add wavelength selective switch 50 on the basis of a command from the control unit of the computer 81, so that the light constituting the backbone network N is controlled. A pulsed optical signal is transmitted to the fiber (arrow T20 in FIGS. 2 and 4).

Here, a specific method for transmitting light having a desired wavelength as a pulsed optical signal will be described by taking the add wavelength selective switch 50 shown in FIG. 3 as an example. For example, when an optical signal having a wavelength incident on the second micromirror 51b is to be used as an optical signal for distance measurement, the second micromirror 51b is turned off for a short time from the on state and then turned on again. When DMD is used, it is possible to set the turn-off time to a short time of about 20 ms. Thereby, the reflected light from the second micro mirror 51b is guided to the second output fiber f3 only for a short time. Therefore, by adding the optical signal passing through the second output fiber f3 to the multiplexed optical signal passing through the backbone network N, the optical signal having a wavelength incident on the second micromirror 51b is pulsed. Thus, it is possible to transmit to the optical fiber constituting the backbone network N.

  The transmitted pulsed optical signal is reflected or scattered at the inspection target position P in the optical fiber constituting the backbone network N. That is, when the inspection target position P is an optical fiber connection place or the like, the pulsed optical signal is reflected by the position. Further, when the inspection target position P is a failure location or the like, the pulsed optical signal is scattered by the position.

  As described above, the return light that is returned by being reflected or scattered at the inspection target position P is branched from the optical fiber constituting the backbone network N by the directional coupler 60 (in FIG. 2 and FIG. 4, arrows T30). Then, the return light branched from the optical fiber by the directional coupler 60 is received by the optical receiver 70.

  In the computer 81, based on the time from when the pulsed optical signal is transmitted from the DMD 51 until the return light is received by the optical receiver 70, the position to be inspected is detected from the add wavelength selective switch 50 or the optical receiver 70. The distance to P is derived. Note that the distance between the two may be derived. Thereby, the inspection target position P can be specified.

<Distance measurement method>
A method (procedure) for measuring the distance from the add wavelength selective switch 50 or the optical receiver 70 to the inspection target position P will be described in more detail.

  In the computer 81, data on the distance (optical path length) from the DMD 51 to the optical receiver 70 is stored in advance. When distance measurement is performed, a pulsed optical signal is transmitted from the DMD 51 to the optical fiber constituting the backbone network N in accordance with a command from the control unit of the computer 81 as described above. In the computer 81, the time from when the pulsed optical signal is transmitted until the return light is received by the optical receiver 70 is measured. Then, in the computer 81, the position to be inspected from the add wavelength selective switch 50 or the optical receiver 70 based on the above measured time and the previously stored data of the distance from the DMD 51 to the optical receiver 70. The distance to P is calculated (derived).

  When the distance is derived, a pulsed optical signal is transmitted a plurality of times, the distance is calculated each time, and an average value of the plurality of calculation results is inspected from the add wavelength selective switch 50 or the optical receiver 70. By deriving the distance to the target position P, the accuracy of the distance can be improved.

<Excellent points of this embodiment>
According to the distance measuring apparatus and the distance measuring method according to the present embodiment, the add wavelength selective switch 50 or the add wavelength selective switch 50 or the add wavelength selective switch 50 provided in the optical multiplexing apparatus 100 emits a pulsed optical signal. The distance from the optical receiver 70 to the inspection target position P can be measured. Therefore, it is possible to specify the inspection target position (failure location or the like) in the optical fiber constituting the backbone network N without using a dedicated tester (OTDR).

  In the present embodiment, the add wavelength selective switch 50 can transmit a pulsed optical signal having a desired wavelength to the optical fiber. Can be specified.

In the present embodiment, a directional coupler 60 and an optical receiver are further provided for the optical multiplexing apparatus 100 including the add wavelength selective switch 50 for transmitting a pulsed optical signal for measuring the distance. 70 is employed. Therefore, the measurement of the time from when the optical signal is transmitted from the add wavelength selective switch 50 to when it is received by the optical receiver 70 can be realized with a simple configuration. That is, for example, in the optical network shown in FIG. 1, the optical multiplexing apparatus installed in a certain place among the plurality of optical multiplexing apparatuses arranged is simply the optical multiplexing apparatus 100 shown in FIG. The above time can be measured.

<Others>
In the above embodiment, the case where a pulsed optical signal is transmitted from the add wavelength selective switch 50 provided in the optical multiplexing apparatus 100 provided with the directional coupler 60 and the optical receiver 70 has been described. However, the add wavelength selective switch 50 that transmits a pulsed optical signal is provided in an optical multiplexing device different from the optical multiplexing device in which the directional coupler 60 and the optical receiver 70 are provided. It is also possible.

  For example, in the optical network shown in FIG. 1, a directional coupler 60 and an optical receiver 70 are provided in the second optical multiplexer 100b disposed at the point B, and the first optical multiplexer disposed at the point A. A pulse-shaped optical signal may be transmitted from the add wavelength selective switch 50 provided in 100a. A case where such a distance measuring device is employed will be described with reference to FIG.

  In the distance measuring apparatus shown in FIG. 5, the directional coupler 60 and the optical receiver 70 are provided in the second optical multiplexing apparatus 100b in the same manner as the optical multiplexing apparatus 100 shown in FIG. When distance measurement is performed, the backbone network N is configured using the optical signal (arrow T11 in the figure) sent from the second transponder 40 to the add wavelength selective switch 50 in the first optical multiplexing device 100a. A pulsed optical signal is transmitted to the optical fiber (arrow T21 in the figure). Then, the return light from the inspection target position is received by the optical receiver 70 provided in the second optical multiplexing apparatus 100b (arrow T31 in the figure).

  Thereby, the distance to a test object position can be measured like the distance measuring apparatus and method mentioned above. When such a distance measuring apparatus is employed, the second transponder 40 and the add wavelength selective switch 50 are not required for the second optical multiplexing apparatus 100b disposed at the point B for distance measurement (see FIG. 5).

  Further, in the above embodiment, when a pulsed optical signal is transmitted from the add wavelength selective switch 50, it is transmitted from the second transponder 40 in the optical multiplexing apparatus 100 provided with the add wavelength selective switch 50. The case where an optical signal to be used is used has been described. However, the light input to the add wavelength selective switch 50 is not limited to such light. For example, a pulse-shaped optical signal is transmitted from the add wavelength selective switch 50 using light transmitted from the second transponder 40 in another optical multiplexer or light from a light source other than the optical multiplexer. It may be. The case where the latter distance measuring device is employed will be described with reference to FIG.

  In the distance measuring apparatus shown in FIG. 6, a directional coupler 91 and a transmitter 92 are attached to an optical fiber constituting the backbone network N. That is, the directional coupler 91 and the transmitter 92 are attached outside the optical multiplexing apparatus 100. When performing distance measurement, an optical signal (arrow T12 in the figure) sent from the transmitter 92 to the add wavelength selective switch 50 in the optical multiplexer 100 via the directional coupler 91 is used. A pulsed optical signal is transmitted to the optical fiber constituting the network N (arrow T22 in the figure). Then, the return light from the inspection target position is received by the optical receiver 70 provided in the optical multiplexing apparatus 100 (arrow T32 in the figure). Thereby, the distance to a test object position can be measured like the distance measuring apparatus and method mentioned above.

  Moreover, although the case where the directional coupler 60 and the optical receiver 70 for receiving the return light are provided in the optical multiplexing device has been described in the above embodiment, these are not necessarily provided in the optical multiplexing device. There is no need. That is, you may attach these directional coupler 60 and the optical receiver 70 to the optical fiber which comprises the backbone network N as an apparatus for exclusive use for receiving return light.

  Moreover, although the case where a pulse-shaped optical signal was transmitted by the wavelength selective switch (MEMS type optical switch) provided with DMD was shown in the said embodiment, an optical switch (optical switching device) is not restricted to this. . That is, other optical switches can be applied as long as they can transmit a pulsed optical signal to the measurement optical fiber using the input light. For example, a waveguide type optical switch is also applicable. However, in the case of a waveguide type optical switch, the pulse length is longer than that of DMD.

  In addition, when specifying the inspection target position on the path through which light of a specific wavelength passes, it is possible to transmit a pulsed optical signal using light of a specific wavelength from a plurality of input light of different wavelengths It is necessary to adopt a simple optical switch. However, when it is not necessary to specify the wavelength, an optical switch that does not have a function of selecting the wavelength can be employed.

(Second Embodiment)
7 and 8 show a second embodiment. In the first embodiment, the case where an optical switch (optical switch) is employed as an optical device that emits a pulsed optical signal using input light has been described. On the other hand, this embodiment demonstrates the case where an optical blocker (light interrupter) is employ | adopted as said optical apparatus. Since the basic configuration is the same as that of the first embodiment, the same configuration is denoted by the same reference numeral, and the description thereof is omitted as appropriate.

  Since the optical blocker itself is a known technique, only the outline will be described with reference to the schematic configuration of FIG. The optical blocker is also provided with optical components such as a lens for condensing light and a collimator lens for converting the diffusing light into parallel light, which are omitted in FIG.

The optical blocker 50X includes a DMD (Digital Micromirror Device) 51X, a fiber array 52X that couples the input fiber f4 and the output fiber f5, and an optical multiplexer / demultiplexer 53X. As described in the above embodiment, the DMD 51X includes a plurality of micro mirrors (first micro mirror 51Xa, second micro mirror 51Xb, third micro mirror 51Xc, fourth micro mirror 51Xd, fifth micro mirror 51Xe, 6 minute mirrors 51Xf).

  A plurality of multiplexed optical signals having different wavelengths input from the input fiber f4 to the optical multiplexer / demultiplexer 53X are demultiplexed into optical signals of the respective wavelengths and are incident on the micromirrors. For example, when the micromirrors are on, the incident light is reflected so as to be guided to the J portion of the optical multiplexer / demultiplexer 53X. When the micromirrors are off, the incident light is removed from the J portion. It is comprised so that it may reflect. Thereby, the reflected light guided to the J part is guided to the output fiber f5 in a state of being multiplexed by the optical multiplexer / demultiplexer 53X (passing state), and is reflected in a direction to be removed from the J part. Is not guided to the output fiber f5 (blocked state).

  As described above, the optical blocker 50X can output an optical signal having an arbitrary wavelength from the multiplexed optical signals having different wavelengths from the output fiber f5, and can block the light having the remaining wavelengths. .

Next, a distance measuring apparatus and method according to the second embodiment of the present invention will be described with reference to FIG. As for the distance measuring apparatus according to the present embodiment, in the first embodiment described above, the configuration other than that in which the add wavelength selective switch 50 is changed to the optical blocker 50X is basically the configuration shown in FIG. Are the same.

  Also in the present embodiment, similarly to the first embodiment, the light blocker 50X can be used to transmit light having a desired wavelength as a pulsed optical signal. For example, when an optical signal having a wavelength incident on the fourth micromirror 51Xd shown in FIG. 7 is to be used as an optical signal for distance measurement, the fourth micromirror is turned off for a short time after being turned off. To do. Thereby, the reflected light from the fourth micro mirror 51Xd is guided to the output fiber f5 for a short time. Thereby, similarly to the first embodiment, a pulsed optical signal can be transmitted to the optical fiber constituting the backbone network N.

  In the present embodiment, a pulsed optical signal is transmitted to the optical fiber constituting the backbone network N (arrow T20X in the figure) using the optical signal (arrow T10X in the figure) sent from the transmitter 93. As for the transmitter 93, when the transmitter 93 is provided in an apparatus provided with the optical blocker 50X, the one in the apparatus may be used. When the ROADM is provided in the backbone network N, the transmitter 93 is provided in the ROADM. A transponder may be used, or an external transmitter may be used as in the configuration shown in FIG.

  As in the case of the first embodiment, the transmitted pulsed optical signal is reflected or scattered at the inspection target position P in the optical fiber constituting the backbone network N. Then, the return light that is returned by being reflected or scattered at the inspection target position P is branched from the optical fiber constituting the backbone network N by the directional coupler 60 (arrow T30X in FIG. 8). Then, the return light branched from the optical fiber by the directional coupler 60 is received by the optical receiver 70. Thus, as in the case of the first embodiment, the distance from the optical blocker 50X or the optical receiver 70 to the inspection target position P can be derived, and the inspection target position P can be specified. .

  In addition, an optical filter (optical attenuator) can also be employed as an optical device that emits a pulsed optical signal using input light. As the optical filter, the same configuration as the optical blocker 50X shown in FIG. 7 described above can be adopted.

  That is, in the above description, in the configuration shown in FIG. 7, for convenience of explanation, the optical signal demultiplexed to each wavelength has been explained as if each is guided to one minute mirror. In general, optical signals of wavelengths are respectively guided to a plurality of micromirror groups. Therefore, the intensity of the output light can be controlled by controlling the number of micromirrors to be turned on and the micromirrors to be turned off in the group of micromirrors to which an optical signal having a certain wavelength is incident.

  If all the micromirrors in the group of micromirrors to which an optical signal of a certain wavelength is incident are turned off so as not to be guided to the output fiber f5, the optical signal of a certain wavelength can be blocked in the same manner as the optical blocker. it can. Thus, by releasing the blocked state from a state where light of a certain wavelength is blocked for a short time, a pulsed optical signal can be transmitted as in the case of using an optical blocker. Therefore, in the configuration shown in FIG. 8, the inspection target position in the optical fiber can be specified also as an optical filter instead of the optical blocker 50X.

<Others>
In each of the above-described embodiments, a configuration in which an optical signal including location data (data including the distance to the optical receiver 70) and pulse generation time data as information is superimposed on an optical signal used for distance measurement and transmitted. It can also be adopted. In this way, in the computer 81, data on the distance from the optical receiver 70 to the DMDs 51 and 51X (in the case where an optical switch or the like not equipped with a DMD is used) is transmitted. Even if it is not stored in advance, the distance from the optical receiver 70 to the inspection target position P can be derived.

  Further, even if the light transmitted to the DMDs 51 and 51X is continuous light, a pulsed optical signal can be transmitted by the on / off control of the micromirror as described above. Here, the light sent to the DMDs 51 and 51X need not be continuous light, and may be pulsed light. That is, as long as pulsed light can be transmitted from the DMDs 51 and 51X, the light input to the DMDs 51 and 51X may be continuous light or pulsed light. The same applies to other optical switches, optical blockers, and optical filters.

  The present invention can also be applied to a system in which a plurality of (n) input optical fibers and output fibers are connected to one optical multiplexing apparatus. That is, the present invention can also be applied to a case where a plurality of (n) multiplexed lights can be simultaneously processed by a single optical multiplexing device.

  In the above embodiment, in order to specify the inspection target position P in the optical fiber constituting the backbone network N, the distance from the optical receiver 70 or the like to the inspection target position P is measured. The optical fiber to be measured is not limited to the one constituting the backbone network N. For example, in the optical network shown in FIG. 1 described above, it is possible to specify the inspection target position in the optical fiber constituting the local network. In this case, an optical pulse may be transmitted using the drop wavelength selective switch 20 in the optical multiplexing apparatus 100. In addition to the optical switch (which may be an optical blocker or an optical filter) capable of transmitting an optical pulse using input light as described above, the above-described directional coupler and optical receiver are connected to the optical fiber. If so, it is possible to specify the inspection target position in various optical fibers as well as the optical fibers constituting the optical network.

  50: Add wavelength selective switch, 60: Directional coupler, 70: Optical receiver, N: Core network, P: Inspection target position

Claims (13)

Optical switching that can transmit a pulsed optical signal to the measurement optical fiber by switching the output to the measurement optical fiber among a plurality of optical fibers connected to the output side for a predetermined time using the input light And
A directional coupler for branching from the measurement optical fiber return light that is returned when the optical signal transmitted from the optical switch is reflected or scattered at the inspection target position in the measurement optical fiber;
An optical receiver for receiving the return light branched by the directional coupler;
With
Measuring the distance from the optical switch or the optical receiver to the position to be inspected according to the time from when the optical signal is transmitted from the optical switch to when the return light is received by the optical receiver. Characteristic distance measuring device.   2. The optical switch according to claim 1, wherein the optical switch is an optical switch that is capable of transmitting a pulsed optical signal to the measurement optical fiber using input light of a plurality of different wavelengths. Distance measuring device.   The optical switch can be incident on the measurement fiber among the plurality of optical fibers connected to the output side by reflecting an input optical signal with a micro mirror whose inclination position is changed by on / off control. The distance measuring device according to claim 1, further comprising a DMD. By using the input light, the output to the measurement optical fiber connected to the output side is switched from the cut-off state to the pass state for a predetermined time, so that a light-blocking light can be transmitted to the measurement optical fiber. And
A directional coupler for branching the return light returned from the measurement optical fiber by reflecting or scattering the optical signal transmitted from the optical breaker at the inspection target position in the measurement optical fiber;
An optical receiver for receiving the return light branched by the directional coupler;
With
Measuring the distance from the optical interrupter or the optical receiver to the inspection target position according to the time from when the optical signal is transmitted from the optical interrupter to when the return light is received by the optical receiver. Characteristic distance measuring device.   5. The optical circuit breaker according to claim 4, wherein the optical circuit breaker is an optical circuit breaker capable of transmitting a pulsed optical signal to the measurement optical fiber using input light of a plurality of different wavelengths. Distance measuring device.   The optical circuit breaker can be incident on the measurement fiber of the plurality of optical fibers connected to the output side by reflecting an input optical signal with a micro mirror whose inclination position is changed by on / off control. 6. The distance measuring device according to claim 4, further comprising a DMD. An optical attenuator capable of transmitting a pulsed optical signal to the measurement optical fiber by releasing the output to the measurement optical fiber connected to the output side from the cut off state for a predetermined time using the input light; ,
A directional coupler for branching from the measurement optical fiber return light that is returned by reflection or scattering of an optical signal transmitted from the optical attenuator at a position to be inspected in the measurement optical fiber;
An optical receiver for receiving the return light branched by the directional coupler;
With
Measuring a distance from the optical attenuator or the optical receiver to the position to be inspected according to a time from when an optical signal is transmitted from the optical attenuator to when the return light is received by the optical receiver. Characteristic distance measuring device.   The optical attenuator is an optical attenuator capable of transmitting a pulsed optical signal to the measurement optical fiber by using input light of a plurality of different wavelengths. Distance measuring device.   The optical attenuator can be incident on the measurement fiber among the plurality of optical fibers connected to the output side by reflecting an input optical signal with a micro mirror whose inclination position is changed by on / off control. The distance measuring device according to claim 7, further comprising a DMD. The measurement optical fiber is an optical fiber constituting a backbone network,
In an optical multiplexing device including an add optical switch capable of adding light of an arbitrary wavelength to the measurement optical fiber,
4. The optical multiplexing device, wherein the add optical switch is used as the optical switch in the distance measuring device according to claim 1, 2, or 3.   The optical multiplexing apparatus according to claim 10, comprising the directional coupler and the optical receiver in the distance measuring apparatus according to claim 1. A backbone network composed of measurement optical fibers;
A plurality of optical multiplexing devices provided on the backbone network;
A plurality of local networks respectively connected to each optical multiplexer;
In an optical network comprising:
The add optical switch provided in at least one of the plurality of optical multiplexers is used as the optical switch in the distance measuring device according to claim 1, 2, or 3. An optical network characterized by Optical switching that can transmit a pulsed optical signal to the measurement optical fiber by switching the output to the measurement optical fiber among a plurality of optical fibers connected to the output side for a predetermined time using the input light And
A directional coupler for branching from the measurement optical fiber return light that is returned when the optical signal transmitted from the optical switch is reflected or scattered at the inspection target position in the measurement optical fiber;
An optical receiver for receiving the return light branched by the directional coupler;
Use
Transmitting a pulsed optical signal from the optical switch to the measurement optical fiber;
Receiving the return light returned from the inspection target position in the optical fiber by being branched by the directional coupler by the optical receiver;
Deriving a distance from the optical switch or the optical receiver to the inspection target position according to a time from when an optical signal is transmitted from the optical switch to when the return light is received by the optical receiver; ,
A distance measuring method characterized by comprising:

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