Distributed optical fiber sensors for multi-wavelength communication

Abstract

To provide a distributed fiber optic sensor used for multi-wavelength communication, including an interrogator, a first optical add-drop multiplexer, a second optical add-drop multiplexer, and an optical amplifier.SOLUTION: An interrogator is used to transmit detection light to a first optical fiber, and the first optical fiber is used to transmit communication light. A first optical add-drop multiplexer includes a first shared port, a first express port used to transmit the communication light, and a first add-drop port used to transmit the detection light, where the first shared port is optically coupled to the interrogator via the first optical fiber. A second optical add-drop multiplexer includes a second shared port, a second express port, and a second add-drop port, where the second express port is optically coupled to the first express port and the second add-drop port is optically coupled to the first add-drop port. The optical amplifier is installed between the first and second express ports.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a distributed optical fiber sensor used for multi-wavelength communication. [Background technology]

[0002] Distributed optical fiber sensing technology uses optical fiber as an element for detecting the environment, and can input pulse detection light into the optical fiber to generate backscattered light in the optical fiber. The characteristics of the backscattered light from the optical fiber change due to environmental factors in the optical fiber portion (e.g., vibration or temperature change), so it is possible to detect the environmental conditions near the optical fiber by analyzing the change in the characteristics of the backscattered light. Because distributed optical fiber sensing technology must detect backscattered light, the optical fiber line route used cannot use communication devices that only allow unidirectional transmission.

[0003] Furthermore, in order to increase the transmission distance of multi-wavelength communication, the optical fiber used in multi-wavelength communication must use elements such as amplifiers that allow only unidirectional transmission. For this reason, it is difficult to implement distributed optical fiber sensing technology in the optical fiber used in multi-wavelength communication. If a user wants to place a distributed optical fiber sensor at a specific point, the user needs to lay new optical fiber to implement distributed optical fiber sensing technology. This means that the user cannot use the existing optical fiber in the telecommunications network. Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention provides a distributed optical fiber sensor used in multi-wavelength communication, which can simultaneously implement multi-wavelength communication technology and distributed optical fiber sensing technology on the same optical fiber, thereby solving the technical problem that traditional optical fibers cannot be used to implement distributed optical fiber sensing technology. [Means for solving the problem]

[0005] The distributed optical fiber sensor for multi-wavelength communication of the present invention includes an interrogator, a first optical add-drop multiplexer, a second optical add-drop multiplexer, and an optical amplifier. The interrogator is used to transmit detection light to a first optical fiber, and the first optical fiber is used to transmit communication light. The first optical add-drop multiplexer includes a first shared port, a first express port used to transmit the communication light, and a first add-drop port used to transmit the detection light, and the first shared port is optically coupled to the interrogator via the first optical fiber. The second optical add-drop multiplexer includes a second shared port, a second express port, and a second add-drop port, and the second express port is optically coupled to the first express port, and the second add-drop port is optically coupled to the first add-drop port. The optical amplifier is disposed between the first express port and the second express port.

[0006] In one embodiment of the present invention, the above-mentioned distributed optical fiber sensor further includes a detection light processing module, which is disposed between the first add drop port and the second add drop port, and the optical fiber detection light processing module is used to transmit the detection light from the first add drop port to the second add drop port, and is used to transmit the backscattered light corresponding to the detection light from the second optical add drop port to the first optical add drop port.

[0007] In one embodiment of the present invention, the detection light processing module includes a first optical combiner, a second optical combiner and a first optical amplifier. The first optical combiner includes a first port, a second port and a third port, and the first port is optically coupled to the first add / drop port. The second optical combiner includes a fourth port, a fifth port and a sixth port, and the fourth port is optically coupled to the second add / drop port, the fifth port is optically coupled to the second port, and the sixth port is optically coupled to the third port. The first optical amplifier is disposed between the second port and the fifth port, and an input end of the first optical amplifier is optically coupled to the second port, and an output end of the first optical amplifier is optically coupled to the fifth port.

[0008] In one embodiment of the present invention, the detection light processing module further includes a second optical amplifier, the second optical amplifier is disposed between the third port and the sixth port, the input end of the second optical amplifier is optically coupled to the sixth port, and the output end of the second optical amplifier is optically coupled to the third port.

[0009] In one embodiment of the present invention, the detection light processing module further includes an optical filter, the optical filter being disposed between the output end of the first optical amplifier and the fifth port.

[0010] In one embodiment of the present invention, the detection light processing module further includes an optical filter, the optical filter being disposed between the output end of the second optical amplifier and the third port.

[0011] In one embodiment of the present invention, the detection light processing module includes a first optical combiner, a second optical combiner and a second optical amplifier. The first optical combiner includes a first port, a second port and a third port, and the first port is optically coupled to the first add / drop port. The second optical combiner includes a fourth port, a fifth port and a sixth port, and the fourth port is optically coupled to the second add / drop port, the fifth port is optically coupled to the second port, and the sixth port is optically coupled to the third port. The second optical amplifier is disposed between the third port and the sixth port, and the input end of the second optical amplifier is optically coupled to the sixth port and the output end of the first optical amplifier is optically coupled to the third port.

[0012] In one embodiment of the present invention, the first optical coupling device is an optical splitter, the first port is a common port of the optical splitter, and the second port and the third port are a first branch port and a second branch port of the optical splitter respectively.

[0013] In one embodiment of the present invention, the first optical coupling device is an optical circulator. In one embodiment of the present invention, the second optical coupling device is an optical splitter, the fifth port is a common port of the optical splitter, and the fourth port and the sixth port are respectively a first branch port and a second branch port of the optical splitter.

[0014] In one embodiment of the present invention, the second optical coupling device is an optical circulator. In one embodiment of the present invention, the input end of the optical amplifier is optically coupled to a first express port, and the output end of the optical amplifier is optically coupled to a second express port.

[0015] In one embodiment of the present invention, the distributed optical fiber sensor further includes a dense wavelength division multiplexer, which includes a first channel port used for receiving communication light, a second channel port used for receiving detection light, and a common port, the common port being optically coupled to the first shared port.

[0016] In one embodiment of the present invention, the distributed optical fiber sensor further includes a dense wavelength division multiplexer, the dense wavelength division multiplexer including a common port used for receiving the communication light and the detection light, a first channel port used for transmitting the communication light, and a second channel port used for transmitting the detection light, the common port being optically coupled to the second shared port. Effect of the Invention

[0017] In view of the above, the present invention allows a communication optical fiber to be used as a distributed optical fiber sensor without affecting the communication quality of multi-wavelength optical communication. Therefore, existing optical fibers in a telecommunication network can be converted into optical fibers with a function of detecting environmental conditions (e.g., vibration or temperature), thereby expanding the application of conventional optical fiber networks. For example, the present invention enables conventional communication optical fibers to be used for monitoring traffic conditions, monitoring the health of infrastructure, monitoring and control regarding the safety of underground cables, and monitoring and control functions regarding the safety of the homeland, such as earthquake alert or debris flow alert. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram showing the installation of a distributed optical fiber sensor. [Diagram 2]1 is a schematic diagram of a distributed optical fiber sensor used for multi-wavelength communication according to one embodiment of the present invention. [Diagram 3] FIG. 2 is a schematic diagram of a detection light processing module according to one embodiment of the present invention. [Figure 4] FIG. 4 is a schematic diagram of a detection light processing module according to another embodiment of the present invention. [Diagram 5] FIG. 4 is a schematic diagram of a detection light processing module according to another embodiment of the present invention. [Figure 6] FIG. 4 is a schematic diagram of a detection light processing module according to another embodiment of the present invention. [Figure 7] 1 is a schematic diagram of an optical coupling device according to one embodiment of the present invention. [Figure 8] 4 is a schematic diagram of an optical coupling device according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Embodiment Distributed optical fiber sensing technology uses the optical fiber itself as the sensor element, and its detection principle is to send pulse detection light into the optical fiber by an interrogator. The interrogator can receive and analyze the backscattered light generated when the pulse detection light is transmitted along the optical fiber. The backscattered light is affected by environmental factors (e.g., vibration or temperature), and the interrogator can measure the environmental vibration or temperature change at each position of the optical fiber through the backscattered light, as shown in Figure 1.

[0020] In order to receive the backscattered light, the optical fiber line route of the conventional distributed optical fiber sensor should not have a driving / driven element, such as an isolator or an erbium-doped optical fiber amplifier (EDFA), which blocks the backscattered light and feeds it back to the interrogator. Optical fiber line networks have already spread to all over the world due to communication needs. Using the conventional optical fiber as an environmental detection element not only saves the cost of optical fiber construction, but also expands the detection range, so that the conventional optical fiber can be applied to infrastructure health monitoring, homeland security and traffic monitoring, etc. However, in order to increase the communication distance, the current communication system is usually equipped with an optical amplifier that is only allowed for unidirectional transmission. Due to the restriction that the optical fiber line route should not have a driving / driven element, which blocks the backscattered light and feeds it back to the interrogator, the use of the conventional optical fiber in the communication network as an environmental detection element is limited.

[0021] In view of the above, the present invention provides a distributed optical fiber sensor for multi-wavelength communication, which can transmit the detection light or backscattered light while avoiding the route of the one-way transmission element for communication. The transmission route of the detection light or backscattered light can be arranged so that the optical amplifier increases the detection distance. The distributed optical fiber sensor of the present invention can realize distributed optical fiber sensing and multi-wavelength communication using the same optical fiber, and thus can expand the application to the conventional optical fiber network.

[0022] 2 is a schematic diagram of a distributed optical fiber sensor 100 used for multi-wavelength communication according to an embodiment of the present invention. The distributed optical fiber sensor 100 may include an interrogator 01, an optical add / drop multiplexer (OADM) 07, an optical add / drop multiplexer 08, and an optical amplifier 06. In an embodiment, the distributed optical fiber sensor 100 may further include a detection light processing module 10, a dense wavelength division multiplexer (DWDM) 04, a dense wavelength division multiplexer 11, and an optical line route switching mechanism 12. In the distributed optical fiber sensor 100, each element is optically coupled to each other via an optical fiber, and these optical fibers (e.g., optical fiber 05 or optical fiber 13) can simultaneously transmit communication light 03, detection light 02, and backscattered light 09.

[0023] The dense wavelength division multiplexer 04 includes a channel port 41 used to receive the communication light 03, a channel port 42 used to receive the detection light 02 and transmit the backscattered light 09, and a common or line port 43. The communication light 03 has wavelengths λ1, λ2, λ3, ..., λ n The communication lights of different wavelengths are input to the dense wavelength division multiplexer 04 via different channel ports of the dense wavelength division multiplexer 04.

[0024] The interrogator 01 may be optically coupled to a channel port 42 of the dense wavelength division multiplexer 04 via an optical fiber. The interrogator 01 is coupled to a channel port 42 of the dense wavelength division multiplexer 04 at a wavelength of λ sf The detected light 02 having a wavelength of λ can be transmitted to a dense wavelength division multiplexer 04, from which the detected light having a wavelength of λ sbThe interrogator 01 can receive backscattered light 09 corresponding to the detected light 02, which is a distance between the optical fiber 100 and the backscattered light 09. When used for environmental monitoring, the interrogator 01 can analyze whether there is a change in the characteristics of the backscattered light 09, thereby determining whether there is an environmental change in the area passed by the optical fiber of the distributed optical fiber sensor 100. When the interrogator 01 detects that there is a change in the backscattered light 09, the interrogator 01 can output an alert message to inform a user.

[0025] The common port 43 of the dense wavelength division multiplexer 04 can be optically coupled to the dense wavelength division multiplexer 11 via an optical fiber 05, and can transmit the detection light 02 or communication light 03 to the dense wavelength division multiplexer 11 via the optical fiber 05, or can receive backscattered light 09 from the dense wavelength division multiplexer 11 via the optical fiber 05. An optical add-drop multiplexer 07, an optical add-drop multiplexer 08, an optical amplifier 06, and a detection light processing module 10 may be disposed on the route of the optical fiber 05 between the dense wavelength division multiplexer 04 and the dense wavelength division multiplexer 11.

[0026] The optical add / drop multiplexer 07 may include a common port 71, an express port 72, and an add / drop port 73. The common port 43 of the dense wavelength division multiplexer 04 is optically coupled to the common port 71 via an optical fiber 05. Based on this, the interrogator 01 is optically coupled to the common port 71 via the dense wavelength division multiplexer 04 and the optical fiber 05. The dense wavelength division multiplexer 04 can transmit the communication light 03 from the channel port 41 and the detection light 02 from the channel port 42 to the common port 71 of the optical add / drop multiplexer 07 via the optical fiber 05. The optical add / drop multiplexer 07 splits the optical signal received by the common port 71 into the detection light 02 and the communication light 03, and outputs the detection light 02 and the communication light 03 through different channels, where the detection light 02 is output from the add / drop port 73 and the communication light 03 is output from the express port 72.

[0027] The optical add-drop multiplexer 08 may include a shared port 81, an express port 82, and an add-drop port 83. The express port 72 of the optical add-drop multiplexer 07 may be optically coupled to the express port 82 of the optical add-drop multiplexer 08 via the optical amplifier 06. That is, the optical amplifier 06 may be disposed between the express port 72 and the express port 82. The add-drop port 73 of the optical add-drop multiplexer 07 may be optically coupled to the add-drop port 83 of the optical add-drop multiplexer 08 via the detection optical processing module 10. That is, the detection optical processing module 10 may be disposed between the add-drop port 73 and the add-drop port 83.

[0028] The optical amplifier 06 is, for example, an erbium-doped optical amplifier. The input end of the optical amplifier 06 can be optically coupled to an express port 72 of the optical add-drop multiplexer 07, and the output end of the optical amplifier 06 can be optically coupled to an express port 82 of the optical add-drop multiplexer 08. The optical amplifier 06 can transmit optical signals in one direction. The input port of the optical amplifier 06 is connected to the express port 72, and can transmit optical signals from the express port 72 to the express port 82, but cannot transmit optical signals from the express port 82 to the express port 72. Therefore, the route between the express port 72 and the express port 82 is only used to transmit unidirectional transmission light (e.g., communication light 03), and cannot transmit transmission light in the reverse direction (e.g., backscattered light 09). The optical amplifier 06 can receive the communication light 03 from the express port 72 of the optical add-drop multiplexer 07. The optical amplifier 06 amplifies the communication light 03 and can transmit the amplified communication light 03 to an express port 82 of the optical add-drop multiplexer 08 .

[0029] The optical amplifier 06 is used to amplify the communication light 03, thereby extending the optical communication distance. The detection light 02 and the multi-wavelength communication light 03 may be transmitted in the same direction or in opposite directions. If the detection light 02 and the communication light are transmitted in opposite directions, the detection light 02 cannot pass through the optical amplifier 06. If the detection light 02 and the communication light are transmitted in the same direction, the noise amplified by the optical amplifier 06 affects the optical fiber sensing performance, and the backscattered light 09 cannot pass through the optical amplifier 06. To solve the above problem, the distributed optical fiber sensor 100 of the present invention can change and transmit the detection light 02 (or the backscattered light 09) via the detection light processing module 10, bypassing the optical amplifier 06.

[0030] The detection light processing module 10 can transmit optical signals in both directions. The detection light processing module 10 can transmit an optical signal from the add-drop port 73 to the add-drop port 83, and can also transmit an optical signal from the add-drop port 83 to the add-drop port 73. Therefore, the route between the add-drop port 73 and the add-drop port 83 can be used to transmit detection light (e.g., detection light 02) or backscattered light (e.g., backscattered light 09). Specifically, the detection light processing module 10 can receive the detection light 02 from the add-drop port 73 of the optical add-drop multiplexer 07 and transmit the detection light 02 to the add-drop port 83 of the optical add-drop multiplexer 08. In addition, the detection light processing module 10 can receive the backscattered light 09 from the add-drop port 83 of the optical add-drop multiplexer 08 and transmit the backscattered light 09 to the add-drop port 73 of the optical add-drop multiplexer 07.

[0031] The optical add-drop multiplexer 08 can focus optical signals such as the communication light 03 acquired by the express port 82 and the detection light 02 acquired by the add-drop port 83, and output the focused optical signal to the dense wavelength division multiplexer 11 via the shared port 81. In addition, the shared port 81 of the optical add-drop multiplexer 08 can receive backscattered light 09 from the direction of the dense wavelength division multiplexer 11. The add-drop port 83 of the optical add-drop multiplexer 08 can transmit the backscattered light 09 to the add-drop port 73 of the optical add-drop multiplexer 07 via the detection light processing module 10.

[0032] The dense wavelength division multiplexer 11 includes a common port 115 used to receive the communication light 03 and the detection light 02, which is optically coupled to the shared port 81 of the optical add-drop multiplexer 08. The dense wavelength division multiplexer 11 can be optically coupled to the dense wavelength division multiplexer 04 via the common port 115, and can receive the focused communication light 03 and the detection light 02 via the common port 115, or can transmit the backscattered light 09 to the dense wavelength division multiplexer 04 via the common port 115.

[0033] The dense wavelength division multiplexer 11 may further include one or more channel ports 111 used to transmit the communication light 03, and may include a channel port 112 used to receive the backscattered light 09 or transmit the detection light 02. After obtaining the focused optical signal, the dense wavelength division multiplexer 11 may split the focused optical signal into the communication light 03 and the detection light 02. The communication light 03 has wavelengths λ1, λ2, λ3, ..., λ nThe communication light of different wavelengths may be output via a channel port 111 of the dense wavelength division multiplexer 11. The detection light 02 may be output via a channel port 112 of the dense wavelength division multiplexer 11 to the optical line route switch mechanism 12, which is used to connect the channel port 112 to another optical fiber 13, thereby extending the detection range of the distributed optical fiber sensor 100. The channel port 112 may receive the backscattered light 09 from the optical fiber 13 via the optical line route switch mechanism 12, and transmit the backscattered light 09 to the shared port 81 of the optical add-drop multiplexer 08.

[0034] 3 is a schematic diagram of a detected light processing module 10 according to one embodiment of the present invention. The light processing module 10 may include an optical fiber 23. The add-drop port 73 of the optical add-drop multiplexer 07 may transmit the detected light 02 to the add-drop port 83 of the optical add-drop multiplexer 08 via the optical fiber 23. The add-drop port 83 of the optical add-drop multiplexer 08 may transmit the backscattered light 09 to the add-drop port 73 of the optical add-drop multiplexer 07 via the optical fiber 23.

[0035] 4 is a schematic diagram of a detection light processing module 10 according to another embodiment of the present invention, which can be used to improve the communication quality of the detection light 02. The detection light processing module 10 may include an optical combiner 50, an optical amplifier 16, an optical filter 17, and an optical combiner 60. The optical combiner 50 may include a port 51, a port 52, and a port 53. The port 51 of the optical combiner 50 can be optically coupled to an add-drop port 73 of the optical add-drop multiplexer 07. The optical combiner 60 may include a port 61, a port 62, and a port 63. The port 61 of the optical combiner 60 can be optically coupled to an add-drop port 83 of the optical add-drop multiplexer 08. The port 52 of the optical combiner 50 can be optically coupled to the port 62 of the optical combiner 60 via an optical fiber 23, and the optical amplifier 16 and the optical filter 17 can be disposed on the optical fiber 23. A port 53 of the optical coupler 50 can be optically coupled to a port 63 of an optical coupler 60 via an optical fiber 20 .

[0036] The optical amplifier 16 is disposed between the port 52 of the optical combiner 50 and the port 62 of the optical combiner 60. The optical amplifier 16 can transmit an optical signal unidirectionally. Specifically, the input end of the optical amplifier 16 can be optically coupled to the port 52, and the output end of the optical amplifier 16 can be optically coupled to the port 62. The optical amplifier 16 can amplify the detection light 02 from the port 52 of the optical combiner 50, and transmit the amplified detection light 02 to the port 62 of the optical combiner 60. The optical filter 17 is disposed between the output end of the optical amplifier 16 and the port 62 of the optical combiner 60, and can be used to filter the detection light 02 amplified by the optical amplifier 16.

[0037] 5 is a schematic diagram of a detection light processing module 10 according to another embodiment of the present invention, which can be used to improve the communication quality of the backscattered light 09. The detection light processing module 10 may include an optical combiner 50, an optical amplifier 21, an optical filter 22, and an optical combiner 60. The optical combiner 50 may include a port 51, a port 52, and a port 53. The port 51 of the optical combiner 50 can be optically coupled to the add-drop port 73 of the optical add-drop multiplexer 07. The optical combiner 60 may include a port 61, a port 62, and a port 63. The port 61 of the optical combiner 60 can be optically coupled to the add-drop port 83 of the optical add-drop multiplexer 08. The port 52 of the optical combiner 50 can be optically coupled to the port 62 of the optical combiner 60 via an optical fiber 23. A port 53 of the optical coupler 50 can be optically coupled to a port 63 of an optical coupler 60 via an optical fiber 20 on which an optical amplifier 21 and an optical filter 22 can be disposed.

[0038] The optical amplifier 21 is disposed between the port 53 of the optical combiner 50 and the port 63 of the optical combiner 60. The optical amplifier 21 can transmit an optical signal in one direction. Specifically, the input end of the optical amplifier 21 can be optically coupled to the port 63, and the output end of the optical amplifier 21 can be optically coupled to the port 53. The optical amplifier 21 can amplify the backscattered light 09 from the port 63 (53) of the optical combiner 60 and transmit the amplified backscattered light 09 to the port 53 of the optical combiner 50. The optical filter 22 can be disposed between the output end of the optical amplifier 21 and the port 53 of the optical combiner 50, and can be used to filter the backscattered light 09 (22) amplified by the optical amplifier 21.

[0039] FIG. 6 is a schematic diagram of a detection light processing module 10 according to another embodiment of the present invention, which can be used to improve the communication quality of the detection light 02 and the backscattered light 09. The detection light processing module 10 (100) may include an optical combiner 50, an optical amplifier 16, an optical filter 17, an optical combiner 60, an optical amplifier 21, and an optical filter 22. The optical combiner 50 may include a port 51, a port 52, and a port 53. The port 51 of the optical combiner 50 can be optically coupled to the add-drop port 73 of the optical add-drop multiplexer 07. The optical combiner 60 may include a port 61, a port 62, and a port 63. The port 61 of the optical combiner 60 can be optically coupled to the add-drop port 83 of the optical add-drop multiplexer 08. The port 52 of the optical combiner 50 can be optically coupled to the port 62 of the optical combiner 60 via an optical fiber 23, and the optical amplifier 16 and the optical filter 17 can be disposed on the optical fiber 23. A port 53 of the optical coupler 50 can be optically coupled to a port 63 of an optical coupler 60 via an optical fiber 20 on which an optical amplifier 21 and an optical filter 22 can be disposed.

[0040] The optical amplifier 16 is disposed between the port 52 of the optical combiner 50 and the port 62 of the optical combiner 60. The optical amplifier 16 can transmit an optical signal in one direction. Specifically, the input end of the optical amplifier 16 can be optically coupled to the port 52, and the output end of the optical amplifier 16 can be optically coupled to the port 62. The optical amplifier 16 can amplify the detection light 02 from the port 52 of the optical combiner 50, and transmit the amplified detection light 02 to the port 62 of the optical combiner 60. The optical filter 17 is disposed between the output end of the optical amplifier 16 and the port 62 of the optical combiner 60, and can be used to filter the detection light 02 amplified by the optical amplifier 16.

[0041] The optical amplifier 21 is disposed between the port 53 of the optical combiner 50 and the port 63 of the optical combiner 60. The optical amplifier 21 can transmit an optical signal in one direction. Specifically, the input end of the optical amplifier 21 can be optically coupled to the port 63, and the output end of the optical amplifier 21 can be optically coupled to the port 53. The optical amplifier 21 can amplify the backscattered light 09 from the port 63 (53) of the optical combiner 60 and transmit the amplified backscattered light 09 to the port 53 of the optical combiner 50. The optical filter 22 is disposed between the output end of the optical amplifier 21 and the port 53 of the optical combiner 50, and can be used to filter the backscattered light 09 (22) amplified by the optical amplifier 21.

[0042] In one embodiment, the optical combiner 50 is, for example, an optical splitter 14 as shown in FIG. 7, and the port 51 of the optical combiner 50 may be the common port 141 of the optical splitter 14, and the ports 52 and 53 of the optical combiner 50 may be the branch ports 142 and 143 of the optical splitter 14, respectively.

[0043] In one embodiment, the optical combiner 60 is, for example, an optical splitter 18 as shown in FIG. 7, and the port 61 of the optical combiner 60 may be a common port 181 of the optical splitter 18, and the ports 62 and 63 of the optical combiner 60 may be branch ports 182 and 183, respectively, of the optical splitter 18.

[0044] 8, and the port 51, the port 52, and the port 53 of the optical combiner 50 may be the second port 152, the third port 153, and the first port 151 of the optical circulator 15, respectively. After the detection light 02 enters the second port 152 of the optical circulator 15, the optical circulator 15 can output the detection light 02 via the third port 153. After the backscattered light 09 enters the first port 151 of the optical circulator 15, the optical circulator 15 can output the backscattered light 09 via the second port 152.

[0045] 8, and the port 61, the port 62, and the port 63 of the optical combiner 60 may be the second port 192, the first port 191, and the third port 193 of the optical circulator 19, respectively. After the detection light 02 enters the first port 191 of the optical circulator 19, the optical circulator 19 can output the detection light 02 via the second port 192. After the backscattered light 09 enters the second port 192 of the optical circulator 19, the optical circulator 19 can output the backscattered light 09 via the third port 193.

[0046] From the above, the distributed optical fiber sensor used for multi-wavelength communication of the present invention has the following features and effects. The present invention allows an optical fiber used for communication to be used as a distributed optical fiber sensor in a situation where the communication quality of multi-wavelength communication is not affected, thereby achieving an environmental detection function. The present invention can extend the sensing distance of a distributed optical fiber sensor, convert existing optical fibers in a telecommunication network into distributed optical fibers with a function of detecting various environmental conditions (e.g., vibration or temperature), and expand the application of conventional communication optical fibers to fields such as traffic condition monitoring, monitoring and control regarding the safety of underground cables, and warning against earthquakes or debris flows. The distributed optical fiber sensor of the present invention is composed of elements such as an optical add-drop multiplexer, an optical splitter, an optical circulator, an optical amplifier, and an optical filter. All of the elements used in the present invention are mass-produced products that are easy to obtain and low-cost. Therefore, the present invention allows distributed optical fiber sensors to be installed in users with minimal introduction costs, thereby increasing operating revenue. [Industrial Applicability]

[0047] The distributed optical fiber sensor of the present invention is applicable to the optical communications field. [Explanation of symbols]

[0048] 01 Interrogator 02 Detection light 03 Communication Light 04 Dense Wavelength Division Multiplexer 05, 13, 20, 23 Optical fiber 06, 16, 21 Optical amplifier 07, 08 Optical add-drop multiplexer 09 Backscattered light 10. Detected light processing module 100 Distributed optical fiber sensor 11 Dense Wavelength Division Multiplexer 12 Optical fiber line route switching mechanism 14, 18 Optical splitter 17, 22 Optical filters 15, 19 Optical Circulator 41, 42, 111, 112 Dense Wavelength Division Multiplexer Channel Ports 43, 115 Common port of dense wavelength division multiplexer 141, 181 Optical splitter common port 142, 143, 182, 183 Optical splitter branching ports 181, 191 First port of optical circulator 182, 192 Second port of optical circulator 183, 193 Third port of optical circulator 50, 60 optical coupler 51, 52, 53, 61, 62, 63 ports 71, 81 shared ports 72, 82 Express Port 73, 83 Add / Drop Port

Claims

1. an interrogator adapted to transmit detection light into a first optical fiber adapted to transmit communication light; a first optical add-drop multiplexer including a first shared port optically coupled to the interrogator via the first optical fiber, a first express port used to transmit the communication light, and a first add-drop port used to transmit the detection light; a second optical add / drop multiplexer including a second shared port, a second express port optically coupled to the first express port, and a second add / drop port optically coupled to the first add / drop port; an optical amplifier disposed between the first express port and the second express port; a detection light processing module disposed between the first add / drop port and the second add / drop port, the detection light processing module being used to transmit the detection light from the first add / drop port to the second add / drop port and to transmit backscattered light corresponding to the detection light from the second add / drop port to the first add / drop port; a first dense wavelength division multiplexer including a first common port used to receive the communication light and the detection light, a first channel port used to transmit the communication light, and a second channel port used to transmit the detection light, the first common port being optically coupled to the second shared port; an optical line rerouting mechanism coupled to the second channel port and used to connect the first optical fiber to a second optical fiber; The detection light processing module includes: a first optical coupling device including a first port, a second port, and a third port optically coupled to the first add / drop port; a second optical coupling device including a fourth port optically coupled to the second add / drop port, a fifth port optically coupled to the second port, and a sixth port optically coupled to the third port; a first optical amplifier disposed between the second port and the fifth port, the first optical amplifier having an input end optically coupled to the second port and an output end optically coupled to the fifth port; A distributed optical fiber sensor for use in multi-wavelength communication, comprising:

2. The detection light processing module includes: a second optical amplifier disposed between the third port and the sixth port, the second optical amplifier having an input end optically coupled to the sixth port and an output end optically coupled to the third port; The distributed optical fiber sensor of claim 1 further comprising:

3. The detection light processing module includes: an optical filter disposed between the output end of the first optical amplifier and the fifth port; The distributed optical fiber sensor of claim 1 further comprising:

4. The detection light processing module includes: an optical filter disposed between the output end of the second optical amplifier and the third port; The distributed optical fiber sensor of claim 2 further comprising:

5. The detection light processing module includes: a second optical amplifier disposed between the third port and the sixth port, the second optical amplifier having an input end optically coupled to the sixth port and an output end optically coupled to the third port; The distributed fiber optic sensor of claim 1 further comprising:

6. the first optical coupling device is an optical splitter, the first port is a common port of the optical splitter, and the second port and the third port are a first branch port and a second branch port of the optical splitter, respectively; 2. The distributed optical fiber sensor according to claim 1.

7. The distributed optical fiber sensor of claim 1 , wherein the first optical coupling device is an optical circulator.

8. the second optical coupling device is an optical splitter, the fifth port is a common port of the optical splitter, and the fourth port and the sixth port are a first branch port and a second branch port of the optical splitter, respectively; 2. The distributed optical fiber sensor according to claim 1.

9. 2. The distributed optical fiber sensor of claim 1, wherein the second optical coupling device is an optical circulator.

10. an input end of the optical amplifier is optically coupled to the first express port, and an output end of the optical amplifier is optically coupled to the second express port; 2. The distributed optical fiber sensor according to claim 1.

11. a second dense wavelength division multiplexer including a third channel port adapted to receive the communication light, a fourth channel port adapted to receive the detection light, and a second common port optically coupled to the first shared port; The distributed fiber optic sensor of claim 1 further comprising:

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