Optical communication system, optical node, and optical power supply method

Abstract

The purpose of the present invention is to provide: an optical communication system that can avoid loss of stored energy at each optical node; an optical node; and an optical power supply method.　The present invention provides an optical communication system 301 wherein a plurality of optical nodes (1-1, 1-2, 1-3, ...) are connected in series by an optical fiber 2 in the downstream direction from an upstream controller 13, and the controller 13 performs optical power supply to each of the optical nodes (1-1, 1-2, 1-3, ...). The controller 13 inputs, into an optical fiber 2-0, wavelength multiplexed light in which light of differing wavelengths per optical node 1 is multiplexed. An optical node 1 comprises: an optical branching part (wavelength filter 23) that, of the wavelength multiplexed light from the upstream side, branches and extracts light of a wavelength assigned to the optical node 1, and outputs wavelength multiplexed light including other wavelengths to the downstream side; and photoelectric conversion parts (photoelectric conversion elements 24, 30) that charge storage batteries (26, 27) with light of the wavelength branched by the optical branching part.

Description

[Technical Field]

[0001] The present disclosure relates to an optical communication system that optically powers an optical node, the optical node, and an optical power supply method therefor. [Background technology]

[0002] In optical fiber networks, especially access networks that connect telecommunications carriers and optical terminals, optical line switching is frequently performed to efficiently use facilities during installation and maintenance, such as connecting optical fiber cores to desired routes or changing routes. Normally, such work is performed by visiting the site and physically switching connections, but a technology has been proposed that allows this to be done remotely using optical switches.

[0003] For example, Non-Patent Document 1 reports a technology for connecting and controlling multiple optical nodes that remotely operate optical switches to a communication building equipped with lasers via a single optical fiber. The optical nodes are equipped with self-holding optical switches, enabling optical power supply to and communication with multiple optical nodes using a single laser. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Tomohiro Kawano, Tetsuya Manabe, Akihiro Kuroda, Kazuhide Nakae, Hiroshi Watanabe, Kazunori Katayama, "A Study on Serial Connection Method of Remote Optical Path Switching Nodes", IEICE General Conference 2022, B-13-28 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the system described in Non-Patent Document 1 has a problem in that if the stored energy of the optical node is lost for some reason, the optical switch cannot be controlled, making it difficult to optically power the optical node and communicate with the optical node.

[0006] Therefore, in order to solve the above-mentioned problems, an object of the present invention is to provide an optical communication system, an optical node, and an optical power feeding method that can prevent the loss of stored energy in each optical node. [Means for solving the problem]

[0007] In order to achieve the above object, the optical communication system according to the present invention makes it possible to supply optical power to all optical nodes simultaneously by changing the wavelength of the optical power supply for each optical node.

[0008] Specifically, the optical communication system according to the present invention is an optical communication system in which a plurality of optical nodes are connected in series via optical fibers from an upstream controller in a downstream direction, and the controller optically supplies power to the optical nodes, the controller inputs wavelength-multiplexed light obtained by multiplexing light of different wavelengths for each of the optical nodes into the optical fiber; The optical node comprises: an optical branching unit that branches and extracts light of a wavelength assigned to itself from the wavelength multiplexed light from the upstream side, and outputs the wavelength multiplexed light including other wavelengths to the downstream side; a photoelectric conversion unit that charges a storage battery with light of a wavelength branched by the optical branch unit; The present invention is characterized by comprising:

[0009] Furthermore, an optical node according to the present invention is configured such that a plurality of optical nodes are connected in series from an upstream controller in a downstream direction by optical fibers, and each of the optical nodes is optically powered by the controller, an optical branching unit that branches and extracts light of a wavelength assigned to itself from wavelength-multiplexed light obtained by multiplexing light of wavelengths different for each optical node input into the optical fiber by the controller, and outputs the wavelength-multiplexed light including other wavelengths to a downstream side; a photoelectric conversion unit that charges a storage battery with light of a wavelength branched by the optical branch unit; The present invention is characterized by comprising:

[0010] Furthermore, an optical power supply method according to the present invention is an optical power supply method for supplying power from an upstream controller to an optical node in an optical communication system in which a plurality of optical nodes are connected in series via optical fibers from the upstream controller in a downstream direction, the method comprising: In each of the optical nodes, branching and extracting light of a wavelength assigned to itself from wavelength-multiplexed light obtained by multiplexing light of different wavelengths for each optical node input into the optical fiber by the controller, and outputting the wavelength-multiplexed light including other wavelengths to a downstream side; Charging its storage battery with the branched light of the wavelength assigned to itself; and It is characterized by:

[0011] The controller multiplexes wavelengths of light that differ for each optical node and transmits them to the optical fiber as wavelength-multiplexed light. Each optical node is assigned an exclusive specific wavelength. Each optical node uses a wavelength filter to extract the light of its own wavelength from the wavelength-multiplexed light transmitted from the upstream side of the optical fiber and uses it for optical power supply. This allows the controller to simultaneously supply optical power to all optical nodes.

[0012] Therefore, the present invention can provide an optical communication system, an optical node, and an optical power feeding method that can prevent the loss of stored energy in each optical node.

[0013] Furthermore, in the case of the system described in Non-Patent Document 1, the logical connection between the communication building and the optical node is one-to-one, so while communicating with a certain optical node, communication with other nodes is not possible, and there is also the issue that it is difficult to manage the excess or deficiency of optical power supply for all optical nodes. Furthermore, in the case of the system of Non-Patent Document 1, while communicating with a certain optical node, it is not possible to constantly monitor other optical nodes, which makes it difficult to improve the efficiency of optical power feeding.

[0014] The optical node of the optical communication system of the present invention is characterized by further comprising a control unit that grasps the power storage status of the storage battery and notifies the controller to adjust the light intensity of the light of the wavelength assigned to the optical node. In addition, the optical node of the optical communication system of the present invention further includes an optical receiver that receives light of the wavelength assigned to the optical node and modulated by the controller, and a modulation unit that modulates the light of the wavelength assigned to the optical node based on the notification and transmits it to the controller.

[0015] This optical communication system uses wavelength-multiplexed light, which allows the controller to modulate it and communicate with all optical nodes simultaneously. Therefore, this optical communication system can constantly monitor all optical nodes and manage the excess or deficiency of optical power supply. In particular, energy efficiency can be improved by increasing the optical intensity of wavelengths sent to optical nodes with low stored energy and decreasing the optical intensity of wavelengths sent to optical nodes with sufficient stored energy.

[0016] The optical node of the optical communication system according to the present invention is characterized in that it comprises two storage batteries, one of which is for a load and the other of which is for the control unit.

[0017] When the load of an optical node requires a large amount of power, a voltage drop in the storage battery may occur, causing malfunctions in the control unit. Therefore, by separating the storage battery for the load from the storage battery for the control unit, malfunctions in the control unit can be avoided even when the load requires a large amount of power.

[0018] The above inventions can be combined as much as possible. [Effects of the Invention]

[0019] The present invention can provide an optical communication system, an optical node, and an optical power feeding method that can prevent the loss of stored energy in each optical node. According to the present invention, by preparing a corresponding number of lasers for multiple optical nodes and multiplexing and transmitting the lasers, it is possible to simultaneously realize optical power supply function and optical communication function for multiple optical nodes using a single optical fiber, and communication with optical nodes can be performed at any time, thereby providing a highly reliable optical communication system.

[0020] Furthermore, by constantly monitoring and understanding the amount of power stored in the optical nodes, it becomes possible to control the optimal amount of optical power supply, thereby providing an optical communication system that allows efficient power supply from a remote location. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a diagram illustrating the configuration of an optical communication system and an optical node according to the present invention; [Figure 2] 1A to 1C are diagrams illustrating an optical power supply method according to the present invention. [Figure 3] FIG. 2 is a diagram illustrating a voltage curve resulting from charging of a storage battery. DETAILED DESCRIPTION OF THE INVENTION

[0022] The following description of the preferred embodiments of the present invention will be given with reference to the accompanying drawings. The preferred embodiments described below are examples of the present invention, and the present invention is not limited to the preferred embodiments. In this specification and the drawings, components having the same reference numerals are intended to represent the same components.

[0023] (Embodiment 1) FIG. 1 is a diagram illustrating the configuration of an optical communication system 301 and an optical node 1 according to this embodiment. In the optical communication system 301, a plurality of optical nodes (1-1, 1-2, 1-3, ...) are connected in series via optical fibers 2 from an upstream controller 13 in the downstream direction, and the controller 13 supplies optical power to each of the optical nodes (1-1, 1-2, 1-3, ...).

[0024] In this specification, when describing individual optical nodes, they will be distinguished by symbols such as 1-1, 1-2, 1-3, etc., and when describing content common to all optical nodes, they will be described as "optical node 1." Similarly, when describing individual optical fibers, they will be distinguished by symbols such as 2-0, 2-1, 2-2, 2-3, etc., and when describing content common to all optical fibers, they will be described as "optical fiber 2." In addition, in this specification, the direction toward the controller 13 is referred to as "upstream," and the direction toward the optical node 1-1, optical node 1-2, optical node 1-3, . . . is referred to as "downstream."

[0025] The controller 13 inputs wavelength-multiplexed light, which is obtained by multiplexing light of different wavelengths for each optical node 1, into the optical fiber 2-0. Specifically, the controller 13 includes a control unit 11, a first power supply laser 3-1 that outputs light of a first wavelength, a second power supply laser 3-2 that outputs light of a second wavelength different from the first wavelength, a first modulator 5 that modulates the light from the first power supply laser 3, a second modulator 6 that modulates the light from the second power supply laser 4, an optical circulator 12, a first optical receiver 7, a second optical receiver 8, a WDM coupler 9 that multiplexes downstream signals, and a WDM coupler 10 that demultiplexes upstream signals. The controller 13 is installed in a communications building where power is available. The laser light emitted from the first power supply laser 3 and the second power supply laser 4 is input to the optical fiber 2-0 via the WDM coupler 9 and the optical circulator 12. In FIG. 1, the number of power supply lasers is two, but the number of power supply lasers can be increased or decreased depending on the number of optical nodes.

[0026] The optical nodes 1 are installed, for example, in a location without a power source. Each optical node 1 is connected in series to the controller 13 via optical fibers (2-0, 2-1, 2-2, 2-3, ...). In this way, the optical communication system 301 is characterized by a configuration in which a plurality of optical nodes 1 are connected in series to one controller device 13 via optical fibers 2.

[0027] Optical node 1 is an optical branching unit (wavelength filter 23) that branches and extracts light of a wavelength assigned to itself from wavelength multiplexed light from the upstream side, and outputs wavelength multiplexed light containing other wavelengths to the downstream side; a photoelectric conversion unit (photoelectric conversion elements 24, 30) that charges a storage battery (26, 27) with light of a wavelength branched by the optical branch unit; Equipped with.

[0028] The optical node 1 extracts only the light of the wavelength assigned to the optical node from the wavelength-multiplexed downstream light from the optical fiber 2 using the wavelength filter 23, converts it into electricity using a photoelectric conversion element, and stores it in a storage battery.The storage battery then supplies driving power to all active elements (optical switch 31, etc.) included in the optical node.

[0029] The optical branching unit 20 is a branching ratio coupler, for example, with a branching ratio of 90:10 or 99:1, and branches a larger amount of optical power to the photoelectric conversion element 24 for power supply. The photoelectric conversion element 24 is an element suitable for the long wavelength band of 1300 nm to 1600 nm used for communications, and is made of, for example, indium gallium arsenide. Photoelectric conversion elements with an open circuit voltage of 5 V or less and a conversion efficiency of approximately 30% are readily available. Therefore, the wavelength of light output from each laser in the controller 13 is set to a wavelength corresponding to the photoelectric conversion element.

[0030] Device power storage unit 27 stores the electric power energy converted by photoelectric conversion element 24. Device power storage unit 27 is, for example, an electric double layer capacitor. Note that when supplying voltage to each active element, a boost circuit 28 (such as a DC / DC converter) adjusts the supply voltage as appropriate.

[0031] The light with low optical power branched by the optical branching unit 20 is guided to the optical branching unit 22 via the optical circulator 21 and input to the photoelectric conversion element 30 for receiving the optical signal and the upstream communication unit 29. The photoelectric conversion element 30 receives a control signal from the controller 13. The upstream communication unit 29 is an optical switch that can be turned on and off to determine whether or not to attenuate a portion of the downstream light, and modulates the upstream communication light directed to the controller 13. The upstream communication unit 29 desirably operates at a low voltage and with very little power consumption of a few nW or less; for example, an electrostatically driven MEMS optical switch that requires little drive power and is generally available can be used.

[0032] The optical node 1 has a microcontroller 25 for control purposes. The microcontroller 25 is mainly configured with four functions (1) to (4). (1) Downstream frame analysis function The microcontroller 25 analyzes the downstream frame contained in the downstream light from the controller 13 received by the photoelectric conversion element 30. The frame contains a request for node information, an execution instruction related to switching, and the like. (2) Uplink signal generation function The microcontroller 25, in cooperation with the downstream frame analysis function, modulates the upstream communication unit 29 to generate an upstream signal light. (3) Optical switch operation control function The microcontroller 25 cooperates with the downstream frame analysis function to, for example, read instructions from the controller 13 and operate an optical switch 31 that switches communication services. (4) Power monitoring function The microcontroller 25 monitors the amount of stored energy in the storage battery 27. The microcontroller 25 constantly monitors the amount of stored energy in the storage battery 27 via a voltage monitor or the like, and notifies the controller 13 of the amount via the signal generation function based on a set threshold.

[0033] As described above, the microcontroller 25 is characterized by the fact that the optical node itself manages the amount of stored energy, communicates with the controller 13, and receives execution instructions from the controller 13 by linking the above four functions together.

[0034] The optical node 1 preferably has two storage batteries, one of which (storage battery 27) is for the load (active elements such as optical switch 31) and the other (storage battery 26) is for the control unit (microcontroller 25, upstream communication unit 29).

[0035] The optical node 1 has a microcontroller power storage unit 26 for driving the microcontroller 25 and the upstream communication unit 29, separate from the device power storage unit 27. When an electric double layer capacitor is used as the storage battery 27, a voltage drop occurs due to the influence of internal resistance when a large current is output, which may cause the microcontroller 25 to be reset. To avoid resetting the microcontroller 25, it is preferable to separate the storage battery into one for the microcontroller 25 and one for the optical switch 31. The optical switch 1 can control which storage battery (26 or 27) to store power in by using the load switch A 32.

[0036] Furthermore, since the optical node 1 needs to be driven with very little power, it is sufficient to supply power to components that consume power, such as the boost circuit 28 and the optical switch 31, only when necessary. For this reason, the optical switch 1 is equipped with a load switch B 33 and a load switch C 34. The boost circuit 28 is driven only when the load switch B 33 is ON. Each load switch is arranged on a power supply line from the device power storage unit 27 so that the optical switch 31 is driven only when the load switch C 34 is ON. By adopting this configuration, it is possible to avoid unnecessary power consumption.

[0037] (Embodiment 2) In this embodiment, the explanation will be centered on the power monitoring function described above. The microcontroller 25 of the optical node 1 grasps the state of charge in the storage battery 27 and notifies the controller 13 to adjust the optical intensity of the light of the wavelength assigned to itself.

[0038] FIG. 2 is a flowchart illustrating the power monitoring function. The control unit 11 of the controller 13 monitors and grasps the amount of stored power in each optical node 1 by querying the amount of stored power (step S01). If the amount of power in the device storage battery 27 of any optical node 1-x (x is 1, 2, 3, . . .) is insufficient to operate the optical switch 31 (step S02: No), the control unit 11 increases the output of the power supply laser 3-x corresponding to the optical node 1-x within the upper limit of the optical intensity that can be input to the optical fiber 2 (step S03).

[0039] Furthermore, if the amount of power stored in the device power storage unit 27 of any optical node 1-x (x is 1, 2, 3, . . .) is sufficient ("Yes" in step S02) and there is a surplus ("Yes" in step S04), the control unit 11 reduces the output of the power supply laser 3-x corresponding to the optical node 1-x (step S05). Otherwise ("No" in step S04), the control unit 11 maintains the output of the power supply laser corresponding to the optical node (step S06).

[0040] Here, we will explain the excess or deficiency of the amount of power in the device storage battery 27. Fig. 3 is a diagram illustrating the voltage curve resulting from charging the device storage battery 27. As shown in Fig. 3, when charging begins when the amount of power in the device storage battery 27 is 0, the output voltage of the storage battery 27 passes through a voltage Va that can operate the optical switch 31 and approaches the output voltage Vb of the photoelectric conversion element 24. However, as the output voltage of the storage battery 27 approaches the output voltage of the photoelectric conversion element 24, the rate at which the voltage rises slows.

[0041] 3, a state in which the output voltage of the storage battery 27 is higher than the voltage Va at which the optical switch can be operated is referred to as a "sufficient power state," and a state in which the output voltage of the storage battery 27 is close to the output voltage Vb of the photoelectric conversion element 24, for example, a state in which the voltage value is 90% of the output voltage Vb of the photoelectric conversion element 24, is referred to as a "surplus power state." Also, a state in which the output voltage of the storage battery 27 is lower than the voltage Va at which the optical switch can be operated is referred to as a "deficient power state."

[0042] As described above, by determining whether the amount of power in the device storage battery 27 is excessive or insufficient and notifying the controller 13, the control unit 11 adjusts the output of the power supply laser, thereby enabling optimal power supply to the optical node 1. The same applies to the microcontroller storage battery 26 regarding whether the amount of power in the storage battery is excessive or insufficient.

[0043] (effect) As described in the above embodiments, the optical communication system according to the present invention transmits multiple downstream laser beams supplied from the controller 13 to each optical node 1 via a single path (optical fiber 2). The optical power of the laser beams is not only used to power each optical node 1, but is also instantaneously intensity-modulated in the time domain to serve as control signals for each optical node 1 for both node power management and control of the node's optical switch 31. Therefore, the present invention can simultaneously provide optical power supply and optical switch control functions for multiple optical nodes via a single path, thereby providing a highly reliable optical node system. Furthermore, each optical node is assigned a unique wavelength, and each optical node is equipped with a wavelength filter that extracts that wavelength, enabling individual optical node operation. This facilitates expansion, such as increasing the number of optical nodes included in the system.

[0044] Furthermore, because the light transmitted to multiple optical nodes has a different wavelength, there is no interference with the upstream signals sent to the communication building, and reception can be performed at any time. This makes it possible to respond quickly to alarms from optical nodes, for example, and provides a responsive optical node system.

[0045] Furthermore, the output power of the optical power supply laser supplied to each optical node can be individually adjusted according to the amount of power stored in the optical node and the need for optical switch operation. Therefore, the amount of power consumed by the power supply laser inside the station can be reduced by suppressing the output power of the corresponding laser for optical nodes with low power consumption, and the output power of the corresponding power supply laser can be increased for optical nodes with low power storage, allowing for rapid charging and enabling quick response to optical switch operation requests, etc. [Explanation of symbols]

[0046] 1, 1-1, 1-2, 1-3, ...: optical nodes 2, 2-0, 2-1, 2-2, 2-3, ...: optical fiber 3-1, 3-2, ...: Power supply laser 5: First modulator 6: Second modulator 7: First optical receiver 8: Second optical receiver 9: WDM coupler 10: WDM coupler 11: Control unit 12: Optical circulator 13: Controller 20: Optical coupler 21: Optical circulator 22: Optical coupler 23: Wavelength filter 24: Photoelectric conversion element 25: Microcontroller 26: Microcontroller battery 27: Device battery 28: Boost circuit 29: Upstream communication unit 30: Photoelectric conversion element 31: Optical switch 32: Load switch A 33: Load Switch 34: Load switch C 301: Optical communication systems

Claims

1. An optical communication system in which a plurality of optical nodes are connected in series via optical fibers from an upstream controller in a downstream direction, and the controller optically supplies power to the optical nodes, the controller inputs wavelength-multiplexed light obtained by multiplexing light of different wavelengths for each of the optical nodes into the optical fiber; The optical node comprises: an optical branching unit that branches and extracts light of a wavelength assigned to itself from the wavelength multiplexed light from the upstream side, and outputs the wavelength multiplexed light including other wavelengths to the downstream side; a photoelectric conversion unit that charges a storage battery with light of a wavelength branched by the optical branch unit; a control unit that grasps a charge state of the storage battery and notifies the controller to adjust the light intensity of the light of the wavelength assigned to the control unit; Equipped with The optical communication system is characterized in that there are two storage batteries, one of which is for the load and the other of which is for the control unit.

2. An optical communication system in which a plurality of optical nodes are connected in series via optical fibers from an upstream controller in a downstream direction, and the controller optically supplies power to the optical nodes, the controller inputs wavelength-multiplexed light obtained by multiplexing light of different wavelengths for each of the optical nodes into the optical fiber; The optical node comprises: an optical branching unit that branches and extracts light of a wavelength assigned to itself from the wavelength multiplexed light from the upstream side, and outputs the wavelength multiplexed light including other wavelengths to the downstream side; a photoelectric conversion unit that charges a storage battery with light of a wavelength branched by the optical branch unit; a control unit that grasps a charge state of the storage battery and notifies the controller to adjust the light intensity of the light of the wavelength assigned to the control unit; Equipped with The optical node comprises: an optical receiver that receives light of the wavelength assigned to said optical receiver and modulated by said controller; a modulation unit that modulates light of the wavelength assigned to itself based on the notification and transmits the modulated light to the controller; The optical communication system further comprises:

3. A plurality of optical nodes are connected in series from an upstream controller in a downstream direction by optical fibers, and each of the optical nodes is optically powered by the controller, an optical branching unit that branches and extracts light of a wavelength assigned to itself from wavelength-multiplexed light obtained by multiplexing light of wavelengths different for each optical node input into the optical fiber by the controller, and outputs the wavelength-multiplexed light including other wavelengths to a downstream side; a photoelectric conversion unit that charges a storage battery with light of a wavelength branched by the optical branch unit; a control unit that grasps a charge state of the storage battery and notifies the controller to adjust the light intensity of the light of the wavelength assigned to the control unit; Equipped with The optical node is characterized in that there are two storage batteries, one of which is for a load and the other of which is for the control unit.

4. A plurality of optical nodes are connected in series from an upstream controller in a downstream direction by optical fibers, and each of the optical nodes is optically powered by the controller, an optical branching unit that branches and extracts light of a wavelength assigned to itself from wavelength-multiplexed light obtained by multiplexing light of wavelengths different for each optical node input into the optical fiber by the controller, and outputs the wavelength-multiplexed light including other wavelengths to a downstream side; a photoelectric conversion unit that charges a storage battery with light of a wavelength branched by the optical branch unit; a control unit that grasps a charge state of the storage battery and notifies the controller to adjust the light intensity of the light of the wavelength assigned to the control unit; Equipped with an optical receiver that receives light of the wavelength assigned to said optical receiver and modulated by said controller; a modulation unit that modulates light of the wavelength assigned to itself based on the notification and transmits the modulated light to the controller; The optical node further comprises:

5. In an optical communication system in which a plurality of optical nodes are connected in series from an upstream controller in a downstream direction by optical fibers, an optical power supply method for supplying power from the controller to the optical nodes, comprising: In each of the optical nodes, branching and extracting light of a wavelength assigned to itself from wavelength-multiplexed light obtained by multiplexing light of different wavelengths for each optical node input into the optical fiber by the controller, and outputting the wavelength-multiplexed light including other wavelengths to a downstream side; Charging its storage battery with the branched light of the wavelength assigned to itself; and The control unit of the optical node grasps the power storage state of the storage battery and notifies the controller to adjust the optical intensity of the light of the wavelength assigned to the optical node. It is characterized by The optical power supply method is characterized in that two storage batteries are provided, one of the storage batteries being for the load and the other being for the control unit.

6. In an optical communication system in which a plurality of optical nodes are connected in series from an upstream controller in a downstream direction by optical fibers, an optical power supply method for supplying power from the controller to the optical nodes, comprising: In each of the optical nodes, branching and extracting light of a wavelength assigned to itself from wavelength-multiplexed light obtained by multiplexing light of different wavelengths for each optical node input into the optical fiber by the controller, and outputting the wavelength-multiplexed light including other wavelengths to a downstream side; Charging its storage battery with the branched light of the wavelength assigned to itself; and The control unit of the optical node grasps the power storage state of the storage battery and notifies the controller to adjust the optical intensity of the light of the wavelength assigned to the optical node. It is characterized by an optical receiver of the optical node receiving light at a wavelength assigned to the optical node and modulated by the controller; and a modulation unit of the optical node modulates light of the wavelength assigned to the optical node based on the notification and transmits the modulated light to the controller. An optical power supply method characterized by the above.

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