Optical path switching node, optical fiber network, and optical fiber network test method

Abstract

This disclosure relates to an optical path switching node comprising: a four-way optical switch switchable to any one of a first connection state in which a first port and a second port are internally connected and a third port and a fourth port are internally connected, a second connection state in which the first port and the third port are internally connected and the second port and the fourth port are internally connected, and a third connection state in which the first port and the fourth port are internally connected and the second port and the third port are internally connected; a first optical coupler for coupling test light toward the exterior of the four-way optical switch into an optical path from the first port; a second optical coupler for coupling the test light toward the exterior of the four-way optical switch into an optical path from the second port; a third optical coupler for coupling the test light toward the exterior of the four-way optical switch into an optical path from the third port; and a fourth optical coupler for coupling the test light toward the exterior of the four-way optical switch into an optical path from the fourth port.

Description

[Technical Field]

[0001] The present disclosure relates to an optical path switching node, an optical fiber network to which the optical path switching node is applied, and a method for testing the optical fiber network. [Background technology]

[0002] In an access optical fiber network, optical fiber core wires are used to connect communication devices installed in communication buildings with user terminals installed in user homes, and optical path switching is performed to change the route of the optical fiber core wires. The configuration of a four-way optical switch applied to an optical path switching node is shown in Figure 1, and the configuration of an optical fiber network that applies the four-way optical switch of Figure 1 and its test method are shown in Figures 2 and 3 (see, for example, Non-Patent Document 1).

[0003] In FIG. 1, 10 is a four-way optical switch. The four-way optical switch 10 can have three types of connection states. (1) A first connection state in which the first port P1 and the second port P2 are internally connected, and the third port P3 and the fourth port P4 are internally connected. (2) a second connection state in which the first port P1 and the third port P3 are internally connected, and the second port P2 and the fourth port P4 are internally connected; and (3) A third connection state in which the first port P1 and the fourth port P4 are internally connected, and the second port P2 and the third port P3 are internally connected. It is possible to switch between either of the above.

[0004] 2 and 3, reference numeral 100 denotes a communication device, 101 denotes a distribution frame, 102 denotes an upper loop, 103-1, 103-2, and 103-3 denote lower loops, 104 denotes a user terminal, and 210-1, 210-2, and 210-3 denote optical path switching nodes. The optical path switching nodes 210-1, 210-2, and 210-3 are each provided with the four-way optical switch 10 described in FIG. 1. The first port P1 and the second port P2 of the four-way optical switch 10 are connected to the upper loop, and the third port P3 and the fourth port are connected to the lower loop.

[0005] 2, to connect a communication device 100 installed in a communication building with a user terminal 104 installed in a user's home via the optical fiber network, the four-way optical switch of optical path switching node 210-1 of the upper loop 102 is set to a first connection state, and the four-way optical switch of optical path switching node 210-2 is set to a second connection state. The optical fiber route from the communication device 100 passes through a distribution frame 101 in the communication building, passes through optical path switching node 210-1 of the upper loop 102, is connected to a lower loop 103-2 at optical path switching node 210-2, and reaches the user terminal 104.

[0006] The optical fiber network shown in Fig. 2 is tested using a method as shown in Fig. 3. Test light (dashed line in Fig. 3) with a wavelength different from that of the communication light is added by wavelength multiplexing from the distribution frame 101 in the communication building, and the section up to the user terminal 104 is tested via optical path switching node 210-1, optical path switching node 210-2, and lower loop 103-2 in the upper loop 102 (see, for example, Non-Patent Document 2). Because the test light has a different wavelength from the communication light, the test can be performed without affecting communication even if communication is in progress between the communication device 100 and the user terminal 104. [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] Tomohiro Kawano, Tatsuya Fujimoto, Kazuhide Nakae, Hiroshi Watanabe, Kazunori Katayama, "Study on remote optical path switching nodes for future optical access networks," 2021 Institute of Electronics, Information and Communication Engineers General Conference, B-13-16, 2021 [Non-patent document 2] Hiroshi Watanabe, Tomohiro Kawano, Chisato Fukai, Ryo Koyama, Kazuhide Nakae, Tatsuya Fujimoto, Yoshiteru Abe, Kazunori Katayama, "Remote optical path switching node operated in multistage loop optical access network," 2021 IEICE Society Conference, BK-2-3, 2021 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the configuration of an optical fiber network can also be assumed as shown in Fig. 4. In Fig. 4, 100 is a communication device, 101 is a distribution frame, 102 is an upper loop, 103-1, 103-2 and 103-3 are lower loops, 104-1 and 104-2 are user terminals, and 210-1, 210-2 and 210-3 are optical path switching nodes.

[0009] The four-way optical switch of optical path switching node 210-2 is switched to the third connection state, and the four-way optical switch of optical path switching node 210-3 is switched to the second connection state, so that the user terminals 104-1 and 104-2 are directly connected without the optical fiber route passing through a telecommunications building. In this case, the optical fiber route is the section from the user terminal 104-1 to the optical path switching node 210-2 of the lower loop 103-2, the section from the optical path switching node 210-2 to the optical path switching node 210-3 of the upper loop 102, and the section from the optical path switching node 210-3 to the user terminal 104-2 of the lower loop 103-3.

[0010] The optical fiber network shown in Fig. 4 can be tested using methods such as those shown in Fig. 5 and Fig. 6. In Fig. 5 and Fig. 6, reference numeral 100 denotes a communication device, 101 denotes a distribution frame, 102 denotes an upper loop, 103-1, 103-2 and 103-3 denote lower loops, 104-1 and 104-2 denote user terminals, and 210-1, 210-2 and 210-3 denote optical path switching nodes.

[0011] The test of the optical fiber network shown in Figure 4 is divided into the following sections A and B. Section A: Section from the user terminal 104-1 of the lower loop 103-2 to the optical path switching node 210-2 Section B: A section from the optical path switching node 210-2 to the optical path switching node 210-3 in the upper loop 102 and a section from the optical path switching node 210-3 to the user terminal 104-2 in the lower loop 103-3.

[0012] The test for Section A is carried out in the following procedure, as shown in Figure 5. 1. The optical path switching node 210-2 is switched to the second connection state. 2. Test light (dashed line in FIG. 5) is inserted from the distribution frame 101 in the communications building, and the optical fiber in section A is tested via the upper loop 102.

[0013] The test for Section B is carried out in the following procedure, as shown in Figure 6. 1. The optical path switching node 210-2 is switched to the first connection state. 2. Test light (dashed line in FIG. 6) is inserted from the distribution frame 101 in the communications building, and passes through the upper loop 102 to test the optical fiber in section B.

[0014] To test the optical fiber network using the above procedure, the optical path switching node 210-2 must be switched from the third connection state to the second connection state or the first connection state, which results in a disruption of communication between the user terminals 104-1 and 104-2. If communication is to be disrupted, consent from the user is required. Even if consent is obtained from the user, the optical path switching node 210-2 must be switched multiple times for testing, and then switched back after the testing, which could prolong the disruption of communication.

[0015] The present disclosure aims to provide an optical path switching node that enables testing of an optical fiber network without interrupting communication, an optical fiber network to which the optical path switching node is applied, and a method for testing the optical fiber network. [Means for solving the problem]

[0016] The optical path switching node of the present disclosure includes an optical coupler that couples test light, thereby enabling testing of an optical fiber network without interrupting communication.

[0017] Specifically, the optical path switching node of the present disclosure includes: a first connection state in which the first port and the second port are internally connected and the third port and the fourth port are internally connected; a second connection state in which the first port and the third port are internally connected and the second port and the fourth port are internally connected; and a four-way optical switch that can be switched to either a third connection state in which the first port and the fourth port are internally connected and a fourth connection state in which the second port and the third port are internally connected; a first optical coupler that couples test light to an optical path from the first port in a direction outside the four-way optical switch; a second optical coupler that couples test light to the optical path from the second port in a direction outside the four-way optical switch; a third optical coupler that couples test light to the optical path from the third port in a direction outside the four-way optical switch; a fourth optical coupler that couples test light to the optical path from the fourth port in a direction outside the four-way optical switch; Equipped with.

[0018] Specifically, the optical path switching node of the present disclosure includes: The optical coupler further includes a test light switch that switches the test light to any one of the first optical coupler, the second optical coupler, the third optical coupler, and the fourth optical coupler.

[0019] The optical fiber network of the present disclosure includes the optical path switching node of the present disclosure, thereby enabling testing of the optical fiber network without interrupting communication.

[0020] Specifically, the optical fiber network of the present disclosure comprises: The optical path switching node described above; a first optical fiber connected to the first port via the first optical coupler; a second optical fiber connected to the second port via the second optical coupler; a third optical fiber connected to the third port via the third optical coupler; a fourth optical fiber connected to the fourth port via the fourth optical coupler; Equipped with.

[0021] Specifically, the optical fiber network of the present disclosure comprises: a fifth optical fiber for inputting test light to the first optical coupler in a direction outward from the four-way optical switch; a sixth optical fiber for inputting test light to the second optical coupler in a direction outward from the four-way optical switch; a seventh optical fiber for inputting test light to the third optical coupler in a direction outward from the four-way optical switch; an eighth optical fiber for inputting test light to the fourth optical coupler in a direction outward from the four-way optical switch; The device further comprises:

[0022] Specifically, the optical fiber network of the present disclosure comprises: The optical path switching node described above; a first optical fiber connected to the first port via the first optical coupler; a second optical fiber connected to the second port via the second optical coupler; a third optical fiber connected to the third port via the third optical coupler; a fourth optical fiber connected to the fourth port via the fourth optical coupler; Equipped with.

[0023] Specifically, the optical fiber network of the present disclosure comprises: The test light switch further includes a ninth optical fiber for inputting test light to the test light switch.

[0024] The optical fiber network testing method of the present disclosure utilizes the optical path switching node of the present disclosure to enable testing of the optical fiber network without interrupting communication.

[0025] Specifically, the disclosed optical fiber network testing method includes: Test light is input into at least one of the fifth optical fiber, sixth optical fiber, seventh optical fiber, and eighth optical fiber of the optical fiber network described above to test any of the corresponding first optical fiber, second optical fiber, third optical fiber, and fourth optical fiber.

[0026] Specifically, the disclosed optical fiber network testing method includes: Test light is input into the ninth optical fiber of the optical fiber network described above to test any one of the first optical fiber, second optical fiber, third optical fiber, and fourth optical fiber switched and connected by the test light switch.

[0027] The above-disclosed inventions can be combined as much as possible. [Effects of the Invention]

[0028] According to the present disclosure, it is possible to provide an optical path switching node that enables testing of an optical fiber network without interrupting communication, an optical fiber network that uses the optical path switching node, and a method for testing the optical fiber network. [Brief explanation of the drawings]

[0029] [Figure 1] 1 shows the configuration of a four-way optical switch applied to an optical path switching node. [Figure 2] 1 shows an example of the configuration of an optical fiber network. [Figure 3] An example of testing an optical fiber network is shown. [Figure 4] 1 shows an example of the configuration of an optical fiber network. [Figure 5] An example of testing an optical fiber network is shown. [Figure 6] An example of testing an optical fiber network is shown. [Figure 7] 1 shows an example of the configuration of an optical path switching node. [Figure 8] 1 shows an example of the configuration of a four-way optical switch. [Figure 9] 1 shows an example of the configuration of an optical path switching node. [Figure 10] An example of testing an optical fiber network is shown. [Figure 11] An example of testing an optical fiber network is shown. [Figure 12] An example of testing an optical fiber network is shown. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below. These implementation examples are merely illustrative, and the present disclosure can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. Note that components with the same reference numerals in this specification and drawings indicate the same components.

[0031] The configuration of the optical path switching node and optical fiber network of the present disclosure is shown in Fig. 7. In Fig. 7, 10 is a four-way optical switch, 11-1 is a first optical coupler, 11-2 is a second optical coupler, 11-3 is a third optical coupler, 11-4 is a fourth optical coupler, 20-1 is a first optical fiber, 20-2 is a second optical fiber, 20-3 is a third optical fiber, 20-4 is a fourth optical fiber, 20-5 is a fifth optical fiber, 20-6 is a sixth optical fiber, 20-7 is a seventh optical fiber, 20-8 is an eighth optical fiber, and 110 is an optical path switching node.

[0032] In FIG. 7, the four-way optical switch 10 can have three different connection states. (1) A first connection state in which the first port P1 and the second port P2 are internally connected, and the third port P3 and the fourth port P4 are internally connected. (2) a second connection state in which the first port P1 and the third port P3 are internally connected, and the second port P2 and the fourth port P4 are internally connected; and (3) A third connection state in which the first port P1 and the fourth port P4 are internally connected, and the second port P2 and the third port P3 are internally connected. It is possible to switch between either of the above.

[0033] An example configuration of the four-way optical switch 10 is shown in Figure 8. In Figure 8, 15-1, 15-2, 15-3, and 15-4 are 1x3 optical switches. The 1x3 optical switch 15-1 can switch the optical path to any of the other 1x3 optical switches 15-2, 15-3, and 15-4. The same is true for the 1x3 optical switches 15-2, 15-3, and 15-4. By switching the optical paths of the 1x3 optical switches 15-1, 15-2, 15-3, and 15-4, the four-way optical switch 10 can have three types of connection states. Examples of 1x3 optical switches include mechanical optical switches and MEMS optical switches.

[0034] In FIG. 7, the optical path switching node 110 includes, in addition to the four-way optical switch 10, a first optical coupler 11-1 that couples test light to the optical path from the first port P1 in the direction outside the four-way optical switch 10, a second optical coupler 11-2 that couples test light to the optical path from the second port P2 in the direction outside the four-way optical switch 10, a third optical coupler 11-3 that couples test light to the optical path from the third port P3 in the direction outside the four-way optical switch 10, and a fourth optical coupler 11-4 that couples test light to the optical path from the fourth port P4 in the direction outside the four-way optical switch 10.

[0035] The test light input from the test terminal M1 is coupled by the first optical coupler 11-1 and output from the communication terminal T1. The test light input from the test terminals M2, M3, and M4 is coupled by the second optical coupler 11-2, the third optical coupler 11-3, and the fourth optical coupler 11-4, respectively, and output from the communication terminals T2, T3, and T4, respectively.

[0036] The first optical coupler 11-1, the second optical coupler 11-2, the third optical coupler 11-3, and the fourth optical coupler 11-4 can be optical fiber couplers or optical waveguide couplers. It is preferable to attach a non-reflection terminator to the end point where the optical path of these optical couplers is not connected. This is to prevent unnecessary reflections when testing the optical fiber.

[0037] 7, the optical fiber network of the present disclosure includes an optical path switching node 110, a first optical fiber 20-1 connected to a first port P1 via a first optical coupler 11-1, a second optical fiber 20-2 connected to a second port P2 via a second optical coupler 11-2, a third optical fiber 20-3 connected to a third port P3 via a third optical coupler 11-3, and a fourth optical fiber 20-4 connected to a fourth port P4 via a fourth optical coupler 11-4. These are communication optical fibers.

[0038] 7, the first optical fiber 20-1 is terminated at the communication terminal T1, and the communication terminal T1 and the first port P1 are connected via a first optical coupler 11-1. The second optical fiber 20-2 is terminated at the communication terminal T2, and the communication terminal T2 and the second port P2 are connected via a second optical coupler 11-2. The third optical fiber 20-3 is terminated at the communication terminal T3, and the communication terminal T3 and the third port P3 are connected via a third optical coupler 11-3. The fourth optical fiber 20-4 is terminated at the communication terminal T4, and the communication terminal T4 and the fourth port P4 are connected via a fourth optical coupler 11-4.

[0039] 7, the optical fiber network of the present disclosure may further include a fifth optical fiber 20-5 for inputting test light to the first optical coupler 11-1 in the direction outward from the four-way optical switch 10, a sixth optical fiber 20-6 for inputting test light to the second optical coupler 11-2 in the direction outward from the four-way optical switch 10, a seventh optical fiber 20-7 for inputting test light to the third optical coupler 11-3 in the direction outward from the four-way optical switch 10, and an eighth optical fiber 20-8 for inputting test light to the fourth optical coupler 11-4 in the direction outward from the four-way optical switch 10. These are test optical fibers.

[0040] 7, the fifth optical fiber 20-5 is terminated at the test terminal M1, and the test terminal M1 and the communication terminal T1 are connected via the first optical coupler 11-1. The sixth optical fiber 20-6 is terminated at the test terminal M2, and the test terminal M2 and the communication terminal T2 are connected via the second optical coupler 11-2. The seventh optical fiber 20-7 is terminated at the test terminal M3, and the test terminal M3 and the communication terminal T3 are connected via the third optical coupler 11-3. The eighth optical fiber 20-8 is terminated at the test terminal M4, and the test terminal M4 and the communication terminal T4 are connected via the fourth optical coupler 11-4.

[0041] Another configuration of the optical path switching node and optical fiber network of the present disclosure is shown in Fig. 9. In Fig. 9, 10 is a four-way optical switch, 11-1 is a first optical coupler, 11-2 is a second optical coupler, 11-3 is a third optical coupler, 11-4 is a fourth optical coupler, 12 is a test light switch, 20-1 is a first optical fiber, 20-2 is a second optical fiber, 20-3 is a third optical fiber, 20-4 is a fourth optical fiber, 20-9 is a ninth optical fiber, and 110 is an optical path switching node.

[0042] 7 in that the optical path switching node 110 of the present disclosure further includes a test light switch 12 that switches and connects the test light to any one of the first optical coupler 11-1, the second optical coupler 11-2, the third optical coupler 11-3, and the fourth optical coupler 11-4. The test light input from the test terminal M5 is switched by the test light switch 12, coupled to any one of the first optical coupler 11-1, the second optical coupler 11-2, the third optical coupler 11-3, and the fourth optical coupler 11-4, and output from any one of the communication terminals T1, T2, T3, and T4. Compared to the optical path switching node shown in FIG. 7, the optical path switching node 110 of the present disclosure can reduce the number of test optical fibers to which the test light is input.

[0043] 9, the optical fiber network of the present disclosure includes an optical path switching node 110, a first optical fiber 20-1 connected to a first port P1 via a first optical coupler 11-1, a second optical fiber 20-2 connected to a second port P2 via a second optical coupler 11-2, a third optical fiber 20-3 connected to a third port P3 via a third optical coupler 11-3, and a fourth optical fiber 20-4 connected to a fourth port P4 via a fourth optical coupler 11-4. These are communication optical fibers.

[0044] 9, the first optical fiber 20-1 is terminated at the communication terminal T1, and the communication terminal T1 and the first port P1 are connected via a first optical coupler 11-1. The second optical fiber 20-2 is terminated at the communication terminal T2, and the communication terminal T2 and the second port P2 are connected via a second optical coupler 11-2. The third optical fiber 20-3 is terminated at the communication terminal T3, and the communication terminal T3 and the third port P3 are connected via a third optical coupler 11-3. The fourth optical fiber 20-4 is terminated at the communication terminal T4, and the communication terminal T4 and the fourth port P4 are connected via a fourth optical coupler 11-4.

[0045] The optical fiber network of the present disclosure may further include a ninth optical fiber 20-9 that inputs test light to the test light switch 12. The ninth optical fiber 20-9 is a test optical fiber. In FIG. 9, the ninth optical fiber 20-9 is terminated at the test terminal M5. The test light from the ninth optical fiber 20-9 is input to the test light switch 12, and is switched and connected to any of the first optical coupler 11-1, the second optical coupler 11-2, the third optical coupler 11-3, and the fourth optical coupler 11-4, and is coupled to the outside via any of the couplers.

[0046] The optical fiber network testing method of the present disclosure is shown in Figures 10, 11, and 12. In Figures 10, 11, and 12, 100 is a communication device, 101 is a distribution frame, 102 is an upper loop, 103-1, 103-2, and 103-3 are lower loops, 104-1 and 104-2 are user terminals, 110-1, 110-2, and 110-3 are optical path switching nodes, and 120 is an optical fiber under test.

[0047] For the optical path switching node 110-2 in Figures 10, 11 and 12, the first optical fiber 20-1 shown in Figure 7 or 9 corresponds to the optical fiber in the direction from the optical path switching node 110-2 of the upper loop 102 to the optical path switching node 110-3, the second optical fiber 20-2 corresponds to the optical fiber in the direction from the optical path switching node 110-2 of the upper loop 102 to the optical path switching node 110-1, the third optical fiber 20-3 corresponds to the optical fiber in the counterclockwise direction on the drawing from the optical path switching node 110-2 of the lower loop 103-2, and the fourth optical fiber 20-4 corresponds to the optical fiber in the clockwise direction on the drawing from the optical path switching node 110-2 of the lower loop 103-2.

[0048] 10, 11, and 12, if the optical path switching node 110-2 has the configuration shown in Fig. 7, any one selected from the fifth optical fiber 20-5, the sixth optical fiber 20-6, the seventh optical fiber 20-7, and the eighth optical fiber 20-8 shown in Fig. 7 corresponds to the test optical fiber 120. In Fig. 10, 11, and 12, if the optical path switching node 110-2 has the configuration shown in Fig. 9, the ninth optical fiber 20-9 shown in Fig. 9 corresponds to the test optical fiber 120.

[0049] 10, test light (indicated by a dashed line in FIG. 10) is input to an optical path switching node 110-2 from a distribution frame 101 in a communication building via a test optical fiber 120. The test light input to the optical path switching node 110-2 is input to one of a first optical fiber 20-1, a second optical fiber 20-2, a third optical fiber 20-3, and a fourth optical fiber 20-4 by one of a first optical coupler 11-1, a second optical coupler 11-2, a third optical coupler 11-3, and a fourth optical fiber 11-4 provided in the optical path switching node 110-2. Examples of tests for optical fiber networks include OTDR (Optical Time Domain Reflectometry) and OFDR (Optical Frequency Domain Reflectometry).

[0050] Therefore, according to the optical fiber network testing method of the present disclosure, the first optical fiber 20-1, the second optical fiber 20-2, the third optical fiber 20-3, and the fourth optical fiber 20-4 can be tested regardless of the connection state of the four-way optical switch 10. If the wavelength of the test light is set to be different from the wavelength of the communication light, it is possible to test the optical fiber network without interrupting communication.

[0051] 11 and 12, the four-way optical switch of optical path switching node 210-2 is switched to the third connection state, and the four-way optical switch of optical path switching node 210-3 is switched to the second connection state, so that the user terminals 104-1 and 104-2 are directly connected without the optical fiber route passing through a telecommunications building. In this case, the optical fiber route is the section from the user terminal 104-1 to the optical path switching node 210-2 in the lower loop 103-2, the section from the optical path switching node 210-2 to the optical path switching node 210-3 in the upper loop 102, and the section from the optical path switching node 210-3 to the user terminal 104-2 in the lower loop 103-3.

[0052] Testing of such an optical fiber network can be performed using methods such as those shown in Figures 11 and 12. Testing of the optical fiber network shown in Figures 11 and 12 is divided into the following sections A and B. Section A: Section from the user terminal 104-1 of the lower loop 103-2 to the optical path switching node 210-2 Section B: A section from the optical path switching node 210-2 to the optical path switching node 210-3 in the upper loop 102 and a section from the optical path switching node 210-3 to the user terminal 104-2 in the lower loop 103-3.

[0053] As shown in Fig. 11, the test for section A involves inputting test light (dashed line in Fig. 11) from distribution frame 101 in the telecommunications building to test optical fiber 121, thereby testing the optical fiber network in section A. As shown in Fig. 12, the test for section B involves inputting test light (dashed line in Fig. 12) from distribution frame 101 in the telecommunications building to test optical fiber 121, thereby testing the optical fiber network in section B. The order of the tests for section A and section B does not matter.

[0054] 11 and 12, if the optical path switching node 110-2 has the configuration shown in Fig. 7, in the test of Section A, the eighth optical fiber 20-8 corresponds to the test optical fiber 120. In the test of Section B, the fifth optical fiber 20-5 corresponds to the test optical fiber 120. In Fig. 11 and 12, if the optical path switching node 110-2 has the configuration shown in Fig. 9, the ninth optical fiber 20-9 corresponds to the test optical fiber 120 in both the test of Section A and the test light switch 12 switches and connects the optical path from the ninth optical fiber to the fourth optical coupler 11-4 in Section A and to the first optical coupler 11-1 in Section B.

[0055] Therefore, according to the optical fiber network testing method of the present disclosure, even when user terminals are directly connected, the optical fiber network can be tested without depending on the connection state of the four-way optical switch 10. If the wavelength of the test light is set to be different from the wavelength of the communication light, it is possible to test the optical fiber network without interrupting communication.

[0056] As described above, the present disclosure can provide an optical path switching node that enables testing of an optical fiber network without interrupting communication, an optical fiber network to which the optical path switching node is applied, and a method for testing the optical fiber network. [Industrial Applicability]

[0057] The present disclosure can be applied to the information and communications industry. [Explanation of symbols]

[0058] 10: Four-way optical switch 11-1: First optical coupler 11-2: Second optical coupler 11-3: Third optical coupler 11-4: Fourth optical coupler 12: Test light switch 15-1, 15-2, 15-3 and 15-4: 1x3 optical switches 20-1: First optical fiber 20-2: Second optical fiber 20-3: Third optical fiber 20-4: Fourth optical fiber 20-5: The fifth optical fiber 20-6: 6th optical fiber 20-7: Seventh optical fiber 20-8: 8th optical fiber 20-9: 9th optical fiber 100: Communication equipment 101: Wiring rack 102: Upper loop 103-1, 103-2 and 103-3: Lower loop 104-1, 104-2: User terminals 110-1, 110-2 and 110-3: Optical path switching nodes 120: Test optical fiber

Claims

1. a first connection state in which the first port and the second port are internally connected and the third port and the fourth port are internally connected; a second connection state in which the first port and the third port are internally connected and the second port and the fourth port are internally connected; and a four-way optical switch that can be switched between a first connection state and a third connection state in which the first port and the fourth port are internally connected and the second port and the third port are internally connected; a first optical coupler for coupling test light to an optical path from the first port in a direction outward from the four-way optical switch; a second optical coupler that couples test light to the optical path from the second port in a direction outside the four-way optical switch; a third optical coupler that couples test light to the optical path from the third port in a direction outside the four-way optical switch; a fourth optical coupler that couples test light to the optical path from the fourth port in a direction outside the four-way optical switch; An optical path switching node comprising:

2. 2. The optical path switching node according to claim 1, further comprising a test light switch that switches and connects test light to any one of the first optical coupler, the second optical coupler, the third optical coupler, and the fourth optical coupler.

3. an optical path switching node according to claim 1; a first optical fiber connected to the first port via the first optical coupler; a second optical fiber connected to the second port via the second optical coupler; a third optical fiber connected to the third port via the third optical coupler; a fourth optical fiber connected to the fourth port via the fourth optical coupler; 1. An optical fiber network comprising:

4. a fifth optical fiber for inputting test light to the first optical coupler in a direction outward from the four-way optical switch; a sixth optical fiber for inputting test light to the second optical coupler in a direction toward the outside of the four-way optical switch; a seventh optical fiber for inputting test light to the third optical coupler in a direction outward from the four-way optical switch; an eighth optical fiber for inputting test light to the fourth optical coupler in a direction toward the outside of the four-way optical switch; 4. The optical fiber network of claim 3, further comprising:

5. an optical path switching node according to claim 2; a first optical fiber connected to the first port via the first optical coupler; a second optical fiber connected to the second port via the second optical coupler; a third optical fiber connected to the third port via the third optical coupler; a fourth optical fiber connected to the fourth port via the fourth optical coupler; 1. An optical fiber network comprising:

6. 6. The optical fiber network according to claim 5, further comprising a ninth optical fiber for inputting test light to said test light switch.

7. 5. A method for testing an optical fiber network, comprising inputting test light into at least one of the fifth optical fiber, the sixth optical fiber, the seventh optical fiber, and the eighth optical fiber of the optical fiber network described in claim 4, to test any of the corresponding first optical fiber, the second optical fiber, the third optical fiber, and the fourth optical fiber.

8. A method for testing an optical fiber network, comprising inputting test light into a ninth optical fiber of the optical fiber network described in claim 6, and testing any one of the first optical fiber, the second optical fiber, the third optical fiber, and the fourth optical fiber that are switched and connected by the test light switch.

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