Optical connection node
Patent Information
- Application Number
- JP2024043434
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-03-19
- Publication Date
- 2025-10-02
Smart Images
Figure 2025143920000001_ABST
Abstract
Description
[Technical Field]
[0001] The present disclosure relates to an optical connection node that connects two optical transmission lines having different numbers of cores. [Background technology]
[0002] Non-Patent Document 1 discloses an optical submarine cable using a multi-core optical fiber (MCF). MCF is an optical fiber containing multiple cores. By using MCF, the transmission capacity of an optical transmission line can be increased. MCF can be used in long-distance optical transmission systems, etc. [Prior art documents] [Non-patent literature]
[0003] [Non-Patent Document 1] Boosting Subsea Cables with Multi-Core Fiber Technology, [online], September 13, 2023, [Retrieved February 16, 2024] <URL:https: / / cloud.google.com / blog / products / infrastructure / delivering-multi-core-fiber-technology-in-subsea-cables?hl=en> Summary of the Invention [Problem to be solved by the invention]
[0004] Since currently installed optical cables mainly accommodate single-core optical fibers (SCFs) with only one core, situations may arise where an optical transmission system must be constructed by mixing a first optical transmission line made up of an MCF and a second optical transmission line made up of an SCF. In such cases, it may be impossible to secure the same number of SCFs as the number of cores contained in one MCF, that is, a situation may arise where all optical signals carried by the multiple cores of the first optical transmission line must be carried by the second optical transmission line, which has fewer cores than the first optical transmission line.
[0005] The present disclosure provides an optical connection node that connects two optical transmission lines having different numbers of cores. [Means for solving the problem]
[0006] According to one aspect of the present disclosure, an optical connection node that connects a first optical transmission line including N cores used to transmit signal light of a first band and a second optical transmission line including M cores used to transmit signal light of each of the first band to Q-th band includes M wavelength multiplexing / demultiplexing devices, each of the M wavelength multiplexing / demultiplexing devices having a q-th port for inputting / outputting signal light of a q-th band (q is an integer from 1 to Q) and a wavelength multiplexing port for inputting / outputting each of the signal light of the first band to the Q-th band, and the M wavelength multiplexing ports of the M wavelength multiplexing / demultiplexing devices are configured to be connected one-to-one with the M cores of the second optical transmission line. and a connecting means including a p-th wavelength converting means connected to a first port of one of the M wavelength multiplexing / demultiplexing devices, and performing wavelength conversion between the p-th band and the first band, wherein, of the signal light of the first band transmitted through the N cores of the first optical transmission line, a first signal light that is transmitted as signal light of the first band in the second optical transmission line is connected to a first port of one of the M wavelength multiplexing / demultiplexing devices, and the connecting means connects, of the signal light of the first band transmitted through the N cores of the first optical transmission line, a p-th signal light that is transmitted as signal light of the p-th band in the second optical transmission line to the p-th wavelength converting means, wherein N is an integer equal to or greater than 2, Q is an integer equal to or greater than 2, and M is an integer smaller than N and equal to or greater than N divided by Q. [Effects of the Invention]
[0007] According to the present disclosure, an optical connection node is provided that connects two optical transmission lines having different numbers of cores. [Brief explanation of the drawings]
[0008] [Figure 1] FIG. 2 is a diagram showing an example of the configuration of an optical connection node. [Figure 2] FIG. 2 is a diagram showing an example of signal light carried in a first optical transmission line and a second optical transmission line. [Figure 3] FIG. 2 is a diagram showing an example of the configuration of an optical connection node. [Figure 4] FIG. 2 is a diagram showing an example of signal light carried in a first optical transmission line and a second optical transmission line. [Figure 5] FIG. 2 is a diagram showing an example of the configuration of an optical connection node. [Figure 6] FIG. 2 is a diagram showing an example of signal light carried in a first optical transmission line and a second optical transmission line. [Figure 7] FIG. 2 is a diagram showing an example of the configuration of an optical connection node. DETAILED DESCRIPTION OF THE INVENTION
[0009] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention as claimed, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the features described in the embodiments may be arbitrarily combined. Furthermore, the same reference numerals are used for the same or similar components, and redundant explanations will be omitted.
[0010] First Embodiment The optical connection node according to this embodiment connects a first optical transmission line and a second optical transmission line. As shown in Fig. 1, the first optical transmission line is one MCF having N cores, and the second optical transmission line is M SCFs. In the following description, the N cores included in the first optical transmission line will be referred to as the first core to the Nth core, and the M cores included in the second optical transmission line will be referred to as the first core to the Mth core.
[0011] Each of the first to Nth cores of the first optical transmission line carries a plurality of optical signals in one band (bandwidth) B#1, and each of the first to Mth cores of the second optical transmission line is used to carry a plurality of optical signals in each of Q bands B#1 to B#Q. N is an integer equal to or greater than 2, Q is an integer equal to or greater than 2, and M is an integer smaller than N and equal to or greater than the number obtained by dividing N by Q. In the following description, as shown in FIG. 1, the direction from the first optical transmission line to the second optical transmission line is referred to as the first direction, and the direction from the second optical transmission line to the first optical transmission line is referred to as the second direction.
[0012] FIG. 1 shows an example of the configuration of an optical connection node where Q=2 and M=N / 2. The optical connection node includes M wavelength multiplexing / demultiplexing devices (WDMs) 5-1 to 5-M. In the following description, the WDMs 5-1 to 5-M are collectively referred to as WDMs 5. The WDM 5 wavelength-multiplexes the signal light of band B#1 input to port #1 and the signal light of band B#2 input to port #2 and outputs the multiplexed signal from the wavelength multiplexing port, and also outputs the signal light of band B#1 input to the wavelength multiplexing port from port #1 and the signal light of band B#2 input to the wavelength multiplexing port from port #2. In other words, it is an optical device that performs wavelength multiplexing / demultiplexing. A total of M wavelength multiplexing ports of the M WDMs 5 are configured to be connected one-to-one to M cores of the second optical transmission line.
[0013] The optical connection node further includes a connection unit 10. In this example, the connection unit 10 includes M wavelength conversion units 2-1 to 2-M. In the following description, the wavelength conversion units 2-1 to 2-M will also be collectively referred to as wavelength conversion unit 2. The wavelength conversion unit 2 is an optical device that converts the wavelength of signal light between band B#1 and band B#2. The connection unit 10 further includes a fan-in / fan-out (FIFO) 1. The fan-in / fan-out (FIFO) 1 is an optical device for connecting N cores of the first optical transmission line to N cores of SCFs in the connection unit 10 on a one-to-one basis. The FIFO 1 has N ports for connecting to the N cores of SCFs in the connection unit 10. In this example, the connection unit 10 connects M (=N / 2) of the N ports of the FIFO1 to M ports #1 of the M WDMs 5 in a one-to-one relationship, and also connects the remaining M of the N ports of the FIFO1 to M wavelength converters 2 in a one-to-one relationship. Furthermore, the connection unit 10 connects the M wavelength converters 2 to M ports #2 of the M WDMs 5 in a one-to-one relationship.
[0014] In the example of Figure 1, the odd-numbered cores of the first optical transmission line are used to transmit signal light in a first direction, the even-numbered cores of the first optical transmission line are used to transmit signal light in a second direction, and each core of the second optical transmission line is used to transmit signal light of band B#1 in the first direction and signal light of band B#2 in the second direction.
[0015] The connection unit 10 connects the (2k-1)th core (k is an integer from 1 to N / 2=M) of the first optical transmission line to port #1 of the WDM 5-k. Therefore, the signal light of band B#1 from the (2k-1)th core of the first optical transmission line is output directly to the kth core of the second optical transmission line. The connection unit 10 also connects the 2kth core of the first optical transmission line to port #2 of the WDM 5-k via the wavelength conversion unit 2-k. Therefore, the signal light of band B#2 from the kth core of the second optical transmission line is converted into signal light of band B#1 by the wavelength conversion unit 2-k and output to the 2kth core of the first optical transmission line.
[0016] Fig. 2(A) shows the signal light carried by the (2k-1)th core of the first optical transmission line, Fig. 2(B) shows the signal light carried by the 2kth core of the first optical transmission line, and Fig. 2(C) shows the signal light carried by the kth core of the second optical transmission line. Each vertical line in each band represents a signal light.
[0017] In the configuration example of Figure 1, odd-numbered cores of the first optical transmission line carry signal light in a first direction, even-numbered cores of the first optical transmission line carry signal light in a second direction, and each core of the second optical transmission line carries both signal light in the first direction and signal light in the second direction.However, since FIFO 1, wavelength conversion unit 2, and WDM 5 are capable of propagating signal light in both directions, the direction of signal light carried by each core is not limited to the form of Figure 1.
[0018] For example, the signal light transmission direction in both the first and second cores of the first optical transmission line can be defined as the first direction, and the signal light transmission direction in both the third and fourth cores of the first optical transmission line can be defined as the second direction. In this case, the first core of the second optical transmission line is used to transmit the signal light of bands B#1 and B#2 in the first direction, and the second core of the second optical transmission line is used to transmit the signal light of bands B#1 and B#2 in the second direction. Furthermore, all N cores of the first optical transmission line can be used only for transmission in the first direction, or only for transmission in the second direction.
[0019] 3 shows an example of the configuration of an optical connection node when Q = 3 and M = N / 3. When Q = 3, the WDM 5 wavelength-multiplexes the signal light of band B#1 input to port #1, the signal light of band B#2 input to port #2, and the signal light of band B#3 input to port #3, and outputs the multiplexed signals from the wavelength multiplexed ports, and also outputs the signal light of band B#1 input to the wavelength multiplexed port from port #1, outputs the signal light of band B#2 input to the wavelength multiplexed port from port #2, and outputs the signal light of band B#3 input to the wavelength multiplexed port from port #3.
[0020] Furthermore, when Q=3, the connection unit 10 is also provided with M wavelength conversion units 3-1 to 3-M. In the following description, the wavelength conversion units 3-1 to 3-M are collectively referred to as wavelength conversion unit 3. The wavelength conversion unit 3 is an optical device that converts the wavelength of signal light between band B#1 and band B#3. In this example, the connection unit 10 connects M ports of a first set of N ports of FIFO1 to M ports #1 of M WDMs 5 in a one-to-one relationship, connects M ports of a second set of N ports of FIFO1 to M wavelength conversion units 2 in a one-to-one relationship, and connects M ports of a third set of N ports of FIFO1 to M wavelength conversion units 3 in a one-to-one relationship. Furthermore, the connection unit 10 connects M wavelength conversion units 2 to M ports #2 of M WDMs 5 in a one-to-one relationship, and connects M wavelength conversion units 3 to M ports #3 of M WDMs 5 in a one-to-one relationship.
[0021] In the example of Figure 3, all cores of the first optical transmission line are used to transmit signal light in a first direction, and all cores of the second optical transmission line are used to transmit signal light of bands B#1 to B#3 in the first direction.
[0022] The connection unit 10 connects the (3k-2)th core (k is an integer between 1 and N / 3=M) of the first optical transmission line to port #1 of the WDM 5-k. Therefore, the signal light of band B#1 from the (3k-2)th core of the first optical transmission line is output directly to the kth core of the second optical transmission line. The connection unit 10 also connects the (3k-1)th core of the first optical transmission line to port #2 of the WDM 5-k via the wavelength converter 2-k. Therefore, the signal light of band B#1 from the (3k-1)th core of the first optical transmission line is converted by the wavelength converter 2-k into signal light of band B#2 and output to the kth core of the second optical transmission line. The connection unit 10 also connects the 3kth core of the first optical transmission line to port #3 of the WDM 5-k via the wavelength converter 3-k. Therefore, the signal light of band B#1 from the 3k-th core of the first optical transmission line is converted into signal light of band B#3 by the wavelength converter 3-k and output to the k-th core of the second optical transmission line.
[0023] Fig. 4(A) shows the signal light carried by the (3k-2)th core of the first optical transmission line, Fig. 4(B) shows the signal light carried by the (3k-1)th core of the first optical transmission line, Fig. 4(C) shows the signal light carried by the 3kth core of the first optical transmission line, and Fig. 4(D) shows the signal light carried by the kth core of the second optical transmission line. Each vertical line in each band represents a signal light.
[0024] In the configuration example shown in FIG. 3 , all cores of the first optical transmission line carry the signal light in a first direction. However, all cores of the first optical transmission line can also carry the signal light in a second direction. That is, the direction of signal transmission in each core of the first optical transmission line can be set arbitrarily. For example, the first, second, and fourth cores of the first optical transmission line can carry the signal light in a first direction, and the third, fifth, and sixth cores can carry the signal light in a second direction. In this case, the first core of the second optical transmission line carries the signal light of bands B#1 and B#2 in the first direction and the signal light of band B#3 in the second direction, and the second core of the second optical transmission line carries the signal light of band B#1 in the first direction and the signal light of bands B#2 and B#3 in the second direction.
[0025] 5 shows an example of the configuration of an optical connection node when Q = 4 and M = N / 4. When Q = 4, the WDM 5 wavelength-multiplexes the signal light of band B#1 input to port #1, the signal light of band B#2 input to port #2, the signal light of band B#3 input to port #3, and the signal light of band B#4 input to port #4, and outputs the multiplexed signals from the wavelength multiplexed ports, and also outputs the signal light of band B#1 input to the wavelength multiplexed port from port #1, outputs the signal light of band B#2 input to the wavelength multiplexed port from port #2, outputs the signal light of band B#3 input to the wavelength multiplexed port from port #3, and outputs the signal light of band B#4 input to the wavelength multiplexed port from port #4.
[0026] Furthermore, when Q=4, the connection unit 10 is also provided with M wavelength conversion units 4-1 to 4-M. In the following description, the wavelength conversion units 4-1 to 4-M are collectively referred to as wavelength conversion unit 4. The wavelength conversion unit 4 is an optical device that converts the wavelength of signal light between band B#1 and band B#4. In this example, the connection unit 10 connects M ports of a first set of N ports of FIFO1 to M ports #1 of M WDMs 5 in a one-to-one relationship, connects M ports of a second set of N ports of FIFO1 to M wavelength conversion units 2 in a one-to-one relationship, connects M ports of a third set of N ports of FIFO1 to M wavelength conversion units 3 in a one-to-one relationship, and connects M ports of a fourth set of N ports of FIFO1 to M wavelength conversion units 4 in a one-to-one relationship. Furthermore, the connection unit 10 connects M wavelength conversion units 2 to M ports #2 of M WDMs 5 in a one-to-one relationship, connects M wavelength conversion units 3 to M ports #3 of M WDMs 5 in a one-to-one relationship, and connects M wavelength conversion units 4 to M ports #4 of M WDMs 5 in a one-to-one relationship.
[0027] In the example of Figure 5, the odd-numbered cores of the first optical transmission line are used to transmit signal light in a first direction, the even-numbered cores of the first optical transmission line are used to transmit signal light in a second direction, and the cores of the second optical transmission line are used to transmit signal light of bands B#1 and B#3 in the first direction and signal light of bands B#2 and B#4 in the second direction.
[0028] The connection unit 10 connects the (4k-3)th core (k is an integer between 1 and N / 4=M) of the first optical transmission line to port #1 of the WDM 5-k. Therefore, the signal light of band B#1 from the (4k-3)th core of the first optical transmission line is output directly to the kth core of the second optical transmission line. The connection unit 10 also connects the (4k-2)th core of the first optical transmission line to port #2 of the WDM 5-k via the wavelength converter 2-k. Therefore, the signal light of band B#2 from the kth core of the second optical transmission line is converted by the wavelength converter 2-k to signal light of band B#1 and output to the (4k-2)th core of the first optical transmission line. The connection unit 10 also connects the (4k-1)th core of the first optical transmission line to port #3 of the WDM 5-k via the wavelength converter 3-k. Therefore, the signal light of band B#1 from the (4k-1)th core of the first optical transmission line is converted to the signal light of band B#3 by the wavelength converter 3-k and output to the kth core of the second optical transmission line. Furthermore, the connection unit 10 connects the 4kth core of the first optical transmission line to port #4 of the WDM 5-k via the wavelength converter 4-k. Therefore, the signal light of band B#4 from the kth core of the second optical transmission line is converted to the signal light of band B#1 by the wavelength converter 4-k and output to the 4kth core of the first optical transmission line.
[0029] Fig. 6(A) shows the signal light carried by the (4k-3)th core of the first optical transmission line, Fig. 6(B) shows the signal light carried by the (4k-2)th core of the first optical transmission line, Fig. 6(C) shows the signal light carried by the (4k-1)th core of the first optical transmission line, Fig. 6(D) shows the signal light carried by the 4kth core of the first optical transmission line, and Fig. 6(E) shows the signal light carried by the kth core of the second optical transmission line. Each vertical line in each band represents a signal light.
[0030] In the configuration example of Figure 5, odd-numbered cores of the first optical transmission line carry signal light in a first direction, even-numbered cores of the first optical transmission line carry signal light in a second direction, and each core of the second optical transmission line carries both signal light in the first direction and signal light in the second direction, but the direction of signal light carried by each core is not limited to the form of Figure 5.
[0031] As described above, in this embodiment, the optical connection node has M WDMs 5. Each of the M WDMs 5 has ports #1 to #Q and a wavelength multiplexing port. A total of M wavelength multiplexing ports of the M WDMs 5 are connected one-to-one to M cores of the second optical transmission line. The WDM 5 outputs signal light of band B#q input to port #q (q is an integer from 1 to Q) from the wavelength multiplexing port, and outputs signal light of band B#q input to the wavelength multiplexing port from port #q.
[0032] The optical connection node further includes a connection unit 10. The connection unit 10 is connected to a p-th port (p is an integer from 2 to Q) of each of the M WDMs 5, and includes a wavelength conversion unit p that performs wavelength conversion between band B#p and band B#1. The connection unit 10 is configured to connect, among the signal light of band B#1 transmitted through the N cores of the first optical transmission line, a first signal light that is transmitted as signal light of band B#1 in the second optical transmission line to port #1 of one of the M WDMs 5, and to connect, among the signal light of band B#1 transmitted through the N cores of the first optical transmission line, a p-th signal light that is transmitted as signal light of band B#p in the second optical transmission line to the wavelength conversion unit p.
[0033] For example, the connection unit 10 has M wavelength conversion units p connected one-to-one to M ports #p of the M WDMs 5. The connection unit 10 connects M first cores of the N cores of the first optical transmission line one-to-one to M ports #1 of the M WDMs 5, and connects M pth cores of the N cores of the first optical transmission line one-to-one to M wavelength conversion units p. The wavelength conversion unit p wavelength-converts signal light of band B#1 input from the pth core of the first optical transmission line to signal light of band B#p and outputs it to port #p of the WDMs 5, and also wavelength-converts signal light of band B#p input from port #p of the WDMs 5 to signal light of band B#1 and outputs it to the pth core of the first optical transmission line.
[0034] Second Embodiment Next, the second embodiment will be described, focusing on the differences from the first embodiment. In this embodiment, an optical switch, for example, a wavelength selective switch (WSS) 6, is provided in the connection unit 10 of the first embodiment. FIG. 7 shows a configuration in which a WSS 6 is provided in the configuration example of FIG. 1 of the first embodiment. N first ports of the WSS 6 are connected one-to-one to N cores of the first optical transmission line via FIFO 1. Furthermore, M second ports of the N second ports of the WSS 6 are connected one-to-one to M ports #1 of M WDMs 5. Furthermore, M p-th ports of the N second ports of the WSS 6 are connected one-to-one to M wavelength conversion units p.
[0035] WSS6 switches the optical signals in units of optical signals so that each of the optical signals in band B#1 input to the first port is output to one of the N second ports, and each of the optical signals in band B#1 input to the second port is output to one of the N first ports. By providing WSS6, the optical signals carried in each of the N cores of the first optical transmission line can be transmitted as optical signals in any of bands B#1 to B#Q in any core of the second optical transmission line.
[0036] <Other forms> In the first and second embodiments, the first optical transmission line is one MCF having N cores, and the second optical transmission line is M SCFs. However, the first optical transmission line may be a plurality of MCFs with a total number of cores of N. Furthermore, the first optical transmission line may be N SCFs. Furthermore, the first optical transmission line may include one or more MCFs and one or more SCFs with a total number of cores of N. Note that FIFO1 is used only for the MCF. Therefore, if the first optical transmission line is N SCFs, there is no need to provide FIFO1 in the connection unit 10.
[0037] Note that band B#1 described in the first and second embodiments may be, for example, C-band or a band within C-band. When Q=2, band B#2 may be S-band, L-band, U-band, a band included in S-band, a band included in L-band, or a band included in U-band. When Q=3, band B#2 may be S-band, L-band, U-band, a band included in S-band, a band included in L-band, or a band included in U-band, and band B#3 may be different from band B#2 and may be S-band, L-band, U-band, a band included in S-band, a band included in L-band, or a band included in U-band. When Q=4, bands B#2 to B#4 may be S-band, L-band, U-band, a band included in S-band, a band included in L-band, or a band included in U-band, but different from each other.
[0038] Furthermore, band B#1 described in the first and second embodiments may be, for example, a band combining C-band and L-band, or a band within the band combining C-band and L-band. Furthermore, band B#1 described in the first and second embodiments may be a band combining C-band and S-band, or a band within the band combining C-band and S-band. Bands B#2 to B#Q may be different bands from band #1 and may be different bands from each other.
[0039] This configuration makes it possible to connect two optical transmission lines with different numbers of cores, thereby contributing to Goal 9 of the United Nations' Sustainable Development Goals (SDGs), which is to "Build resilient infrastructure, promote sustainable industrialization, and foster innovation."
[0040] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention. [Explanation of symbols]
[0041] 5-1~5-M: WDM, 10: Connection section
Claims
1. An optical connection node connecting a first optical transmission line including N cores used to transmit signal light of a first band and a second optical transmission line including M cores used to transmit signal light of each of the first band to Q bands, N is an integer of 2 or more, Q is an integer of 2 or more, M is an integer smaller than N and equal to or greater than the number obtained by dividing N by Q, The optical connection node comprises: M wavelength multiplexing / demultiplexing devices, each of the M wavelength multiplexing / demultiplexing devices having a q-th port for inputting / outputting signal light of a q-th band (q is an integer from 1 to Q) and a wavelength multiplexing port for inputting / outputting signal light of each of the first band to the Q-th band, and the M wavelength multiplexing ports of the M wavelength multiplexing / demultiplexing devices are configured to be connected one-to-one to the M cores of the second optical transmission line; a connecting means including a p-th wavelength converting means connected to a p-th port (p is an integer from 2 to Q) of each of the M wavelength demultiplexing devices and performing wavelength conversion between the p-th band and the first band, wherein the connecting means connects, among the signal light of the first band transmitted through the N cores of the first optical transmission line, a first signal light that is transmitted as signal light of the first band in the second optical transmission line, to a first port of one wavelength demultiplexing device of the M wavelength multiplexing / demultiplexing devices, and connects, among the signal light of the first band transmitted through the N cores of the first optical transmission line, a p-th signal light that is transmitted as signal light of the p-th band in the second optical transmission line to the p-th wavelength converting means; An optical connection node comprising:
2. The connection means is M p-th wavelength conversion means; M first cores among the N cores of the first optical transmission line are connected to M first ports of the M wavelength multiplexing / demultiplexing devices in a one-to-one relationship; 2. The optical connection node according to claim 1, wherein M p-th cores among said N cores of said first optical transmission line are connected to said M p-th wavelength conversion means in a one-to-one relationship.
3. 2. The optical connection node according to claim 1, wherein the connection means is connected to the N cores of the first optical transmission path, the M first ports of the M wavelength multiplexing / demultiplexing devices, and the p wavelength conversion means, and comprises an optical switch that switches the first band signal light between the N cores, the M first ports, and the p wavelength conversion means.
4. 2. The optical connection node according to claim 1, wherein the second optical transmission line includes M single-core optical fibers.
5. The optical connection node according to claim 1 , wherein the first optical transmission line includes one or more multi-core optical fibers having a total number of cores of N.
6. 2. The optical connection node according to claim 1, wherein said first optical transmission line includes N single-core optical fibers.
7. 2. The optical connection node according to claim 1, wherein the first optical transmission line includes one or more multi-core optical fibers having a total number of cores of N and one or more single-core optical fibers.
8. 2. The optical connection node according to claim 1, wherein the first band is a C-band or a band within the C-band.
9. Q is 2, 9. The optical connection node according to claim 8, wherein the second band is an S band, an L band, a U band, a band included in the S band, a band included in the L band, or a band included in the U band.
10. Q is 3, the second band is an S band, an L band, a U band, a band included in the S band, a band included in the L band, or a band included in the U band, 9. The optical connection node according to claim 8, wherein the third band is different from the second band and is an S band, an L band, a U band, a band included in the S band, a band included in the L band, or a band included in the U band.
11. Q is 4, the second band is an S band, an L band, a U band, a band included in the S band, a band included in the L band, or a band included in the U band, the third band is different from the second band and is an S band, an L band, a U band, a band included in the S band, a band included in the L band, or a band included in the U band; 9. The optical connection node according to claim 8, wherein the fourth band is different from the second band and the third band and is an S band, an L band, a U band, a band included in the S band, a band included in the L band, or a band included in the U band.
12. 2. The optical connection node according to claim 1, wherein the first band is a band that combines a C band and an L band, or a band within the band that combines a C band and an L band.
13. 2. The optical connection node according to claim 1, wherein the first band is a band that combines a C band and an S band, or a band within the band that combines a C band and an S band.