Optical node system, node, control device, switching method, and program

Abstract

This optical node system comprises: a first node 1 comprising a light source 11 that outputs light to a second node 2 via an optical fiber 6, and a control device 15 that increases the optical power of the light source 11 and instructs the second node 2 to switch between power storage locations; and the second node 2 comprising a first power storage unit A1 and a second power storage unit A2 that store power converted from the light, and a switching unit 40 that switches the power storage location from the first power storage unit A1 to the second power storage unit A2 if the optical power of the light exceeds a predetermined value.

Description

Optical node system, node, control device, switching method and program

[0001] The present disclosure relates to an optical node system, a node, a control device, a switching method, and a program.

[0002] In optical fiber networks, especially in access networks that connect telecommunications carriers and optical nodes (optical terminals), optical line switching, such as connecting optical fiber cores to arbitrary routes or changing routes, is carried out at a certain frequency to efficiently use the facilities during installation and maintenance.

[0003] While such work is usually performed by a worker visiting the site and physically switching the connection, a technology has been proposed that switches the connection remotely using an optical switch. Non-Patent Document 1 proposes a technology in which an optical node (child node) is connected to an optical fiber and this optical node is driven by an optical fiber power supply.

[0004] Akihiro Kuroda, Tomohiro Kawano, Hiroshi Watanabe, Ikutaro Ogushi, Kazunori Katayama, Tetsuya Manabe, "Study on Energy Storage Control of Remote Optical Path Switching Nodes", IEICE General Conference 2023, B-13-26

[0005] The child node converts the optical fiber power supply energy from the parent node into electrical energy, stores it in a storage unit such as a capacitor, and uses it as a power source to operate, but there is a problem that if the storage unit fails, the child node will become unable to operate.

[0006] One solution to this problem is to provide a spare power storage unit and restore the child node by switching to the spare power storage unit. However, if the power storage unit of the child node fails, the child node will have no power source. In other words, there is no electrical energy to operate the child node, and therefore the child node cannot switch to the spare power storage unit. One solution would be to send a worker to the child node's installation site to switch the child node's power storage unit, but this would take time and incur costs.

[0007] The present disclosure has been made in consideration of the above circumstances, and an object of the present disclosure is to provide a technology for remotely switching the power storage unit of a child node without dispatching a worker to the site.

[0008] In order to achieve the above object, one aspect of the present disclosure is an optical node system comprising a first node and a second node, wherein the first node comprises a light source that outputs light to the second node via an optical fiber, and a control device that increases the optical power of the light source and instructs the second node to switch the storage destination, and the second node comprises a first storage unit and a second storage unit that store electricity converted from the light, and a switching unit that switches the storage destination from the first storage unit to the second storage unit when the optical power of the light exceeds a predetermined value.

[0009] One aspect of the present disclosure is a node powered by optical power supply, comprising: a first storage unit and a second storage unit that store electricity converted from light supplied via an optical fiber; and a switching unit that switches the storage destination from the first storage unit to the second storage unit when the optical power of the light exceeds a predetermined value, wherein the switching unit comprises a contactless switch that is activated when a voltage converted according to the optical power of the light exceeds a predetermined voltage value; and a switching switch that switches the storage destination from the first storage unit to the second storage unit by activating the contactless switch.

[0010] One aspect of the present disclosure is a control device that controls nodes connected via optical fiber, and includes a management unit that queries the node about the amount of energy stored in a storage unit, and a control unit that, if there is no response to the query, increases the optical power of a light source that outputs light to the node via the optical fiber and instructs the node to switch the storage destination.

[0011] One aspect of the present disclosure is a switching method performed by an optical node system including a first node and a second node, wherein the first node outputs light to the second node via an optical fiber, increases the optical power of the light, and instructs the second node to switch the storage destination, the second node includes a first storage unit and a second storage unit that store electricity converted from the light, and when the optical power of the light exceeds a predetermined value, switches the storage destination from the first storage unit to the second storage unit.

[0012] One aspect of the present disclosure is a program that causes a computer to function as the control device.

[0013] According to the present disclosure, it is possible to provide a technique for remotely switching the power storage unit of a child node without dispatching a worker to the site.

[0014] Fig. 1 is a diagram showing the configuration of an optical node system according to this embodiment. Fig. 2 is a diagram showing the configuration of a switching unit according to this embodiment. Fig. 3 is a flowchart showing switching processing according to this embodiment. Fig. 4 is a diagram showing the configuration of a modified example of the switching unit according to this embodiment. Fig. 5 is an example of a hardware configuration.

[0015]

[0023] Embodiments of the present disclosure will be described with reference to the accompanying drawings. The embodiments described below are examples of the present disclosure, and the present disclosure is not limited to the following embodiments. Note that components with the same reference numerals in this specification and drawings indicate the same components.

[0016] FIG. 1 is a diagram showing an example of the configuration of an optical node system according to this embodiment.

[0017] The optical node system of this embodiment includes a parent node 1 (first node) and a child node 2 (second node). The upstream parent node 1 and the downstream child node 2 are connected via an optical fiber 6 (optical fiber transmission line).

[0018] In this embodiment, the direction from child node 2 to parent node 1 is referred to as the "upstream direction," and the direction from parent node 1 to child node 2 is referred to as the "downstream direction." Parent node 1 and child node 2 are also referred to as optical nodes. Light is also referred to as an optical signal in the following description.

[0019] <Parent Node> Parent node 1 is installed in an environment where power supply is ensured (for example, in a communication building). Parent node 1 optically supplies power to child node 2 via optical fiber 6 and controls child node 2 by communicating with child node 2. In this embodiment, if the power storage unit A1 currently in use by child node 2 breaks down, parent node 1 remotely switches to the spare power storage unit A2. For example, if there is no response from child node 2, parent node 1 increases the optical power (output power) of light source 11 and instructs child node 2 to switch between power storage units A1 and A2.

[0020] The illustrated parent node 1 includes a light source 11 , a modulation unit 12 (modulator), a receiving unit 13 (receiver), an optical circulator 14 , and a controller 15 .

[0021] The light source 11 outputs light (power supply light) to the child node 2 via the optical fiber 6. The light source 11 is, for example, a laser diode that emits laser light. The light source 11 in this embodiment is a light source (output variable laser light source) that can change the optical power that indicates the intensity of the light. The light source 11 changes the optical power of the laser light in accordance with instructions from the controller 15.

[0022] Laser light emitted from the light source 11 is input to the optical fiber 6 via the modulator 12 and optical circulator 14. The wavelength of the laser light is, for example, 1310 nm to 1650 nm. The optical power of the laser light is, for example, about +10 to +20 dBm in the case of a Japanese FTTH network. The parent node 1 uses the light from the light source 11 to send and receive upstream and downstream signals.

[0023] In response to instructions from the controller 15, the modulator 12 modulates the light output from the light source 11 to generate a downstream signal (e.g., a control signal), superimposes it on the power supply light output from the light source 11, and outputs it to the child node 2.

[0024] In the example shown in the figure, an external modulation method is used in which the light source 11 and the modulation unit 12 are separate, but the light source 11 may be configured as an internally modulated laser with the functions of the modulation unit 12, and the downstream signal to the child node 2 may be superimposed on the power supply light.

[0025] The receiver 13 receives an upstream signal output from the child node 2 via the optical fiber 6, converts it into an electrical signal, and outputs it to the controller 15. The upstream signal includes a response from the child node 2 to an instruction from the parent node 1. The response from the child node 2 may include, for example, the amount of charge (charge voltage) of the power storage units A and B measured by the child node 2 in response to an inquiry from the parent node 1. The receiver 13 uses a light-receiving element such as a photodiode.

[0026] The optical circulator 14 branches an optical signal in the downstream direction (hereinafter referred to as the "downstream signal") and an optical signal in the upstream direction (hereinafter referred to as the "upstream signal"). The downstream signal and the upstream signal are branched by passing through the optical circulator 14, and a single optical fiber 6 can connect the parent node 1 and the child node 2.

[0027] The controller 15 (control device) controls the parent node 1 and the child node 2 connected via the optical fiber 6. The controller 15 increases the optical power of the light source 11 and instructs the child node 2 to switch the power storage destination (charging destination). The controller 15 may include a management unit 151 and a control unit 152. The management unit 151 may inquire of the child node 2 about the amount of power stored in the power storage unit A1. If there is no response to the inquiry, the control unit 152 may determine that the power storage unit A1 has failed, and may increase the optical power of the light source 11 that outputs light to the child node 2 via the optical fiber 6 and instruct the child node 2 to switch the power storage destination.

[0028] When there is no response from the second node, the control unit 152 may drive the switching unit 40 of the child node 2 to switch the storage unit to which the power is to be stored by increasing the optical power of the light source 11 to a predetermined value or more. For example, when the storage unit A1 is not malfunctioning during normal operation, the control unit 152 controls the light source 11 to output normal optical power. On the other hand, when there is no response from the second node and it is determined that the storage unit A1 has malfunctioned, the control unit 152 controls the light source 11 to output switching optical power, which instructs the storage unit to be switched, instead of the normal optical power. The switching optical power is set to be greater than the normal optical power and equal to or greater than a predetermined value.

[0029] The controller 15 sends a modulated signal to the modulator 12 and superimposes a downstream signal (control signal) to the child node 2 on the power supply light output by the light source 11. The downstream signal includes, for example, an instruction to drive the device 30, a power supply control instruction such as starting / stopping power supply, and an inquiry about the amount of power stored in the power storage units A and B. Furthermore, the controller 15 may control the parent node 1 and the child node 2 based on the upstream signal output from the receiver 13, or may send the upstream signal to a management device (not shown).

[0030] <Child Node> Child node 2 is installed in a location different from parent node 1 and is powered by optical power supplied from parent node 1. For example, child node 2 may be installed in an outdoor manhole, on a utility pole, or in a communications building different from parent node 1. Child node 2 is connected to parent node 1 via optical fiber 6 and is a device capable of storing power through optical power supply. Therefore, child node 2 can be installed in a location without a power source. A specific device 30 is placed in the child node, and device 30 operates according to instructions from parent node 1.

[0031] In the optical node system shown in the figure, one child node 2 is connected to one optical fiber 6, but multiple child nodes 2 may be connected in series or parallel in multiple stages using 1x2 optical switches, optical couplers, etc.

[0032] In this embodiment, child node 2 splits the light (power supply light, communication light) output from parent node 1 using optical coupler 21 at a ratio of, for example, 90:10, and uses the smaller light for communication and the larger light for charging. The light for communication (optical signal) is split at a ratio of, for example, 50:50 by optical coupler 23 via optical circulator 22, and is input to receiving unit 24 and transmitting unit 25, respectively, and processed by control unit 27. The light for charging is converted by photoelectric conversion unit 26 into electrical energy corresponding to the optical power received, and is stored in power storage units A and B. Note that electrical energy will hereinafter also be referred to as power.

[0033] The illustrated child node 2 includes optical couplers 21 and 23 (power branching couplers), an optical circulator 22, a receiving unit 24 (receiver), a transmitting unit 25 (transmitter), an opto-electrical conversion unit 26, a control unit 27, a load switch 28, a voltage boosting unit 29 (voltage boosting element), a device 30, a switching unit 40, and power storage units A and B.

[0034] The optical coupler 21 splits the light output from the parent node 1 into two. The optical coupler 21 is a multiplexer / demultiplexer that can split and multiplex downstream light and upstream light. The optical coupler 21 is a split ratio coupler that splits a larger portion of the downstream optical power output from the parent node 1 to the photoelectric conversion unit 26. The light split by the optical coupler 21, which has a smaller optical power, is guided to the optical circulator 22. The optical coupler 21 may split the optical power at a ratio of, for example, 90:10.

[0035] The optical circulator 22 separates one of the lights branched from the optical coupler 21 into a downstream signal and an upstream signal. The optical coupler 23 branches the light branched by the optical circulator 22. The light branched by the optical coupler 23 is guided to a receiving unit 24 that receives the light as a downstream signal and a transmitting unit 25 that generates an upstream signal. The optical coupler 23 may branch the optical power at a ratio of, for example, 50:50.

[0036] The receiving unit 24 receives, as a downstream signal, one of the lights branched by the optical coupler 23. The receiving unit 24 receives the downstream signal superimposed on the light output from the parent node 1. The receiving unit 24 uses a light receiving element such as a photodiode.

[0037] The transmitter 25 modulates the other light branched by the optical coupler 23 to generate modulated light, and outputs the modulated light to the parent node 1. Specifically, the transmitter 25 includes a reflective optical switch (not shown) that performs modulation synchronized with a signal from the controller 27, and modulates the light branched by the optical coupler 23 with the optical switch to generate modulated light. The modulated light is output to the parent node 1 via the optical fiber 6 as an upstream signal to the parent node 1. The transmitter 25 is preferably one that operates at a low voltage and with low power consumption; for example, a MEMS-type ON / OFF switch using a mirror can be used. Alternatively, a laser light source may be used for the transmitter 25.

[0038] The photoelectric conversion unit 26 converts the other light output from the optical coupler 21 into electrical energy and stores it in the power storage unit A or the power storage unit B. The photoelectric conversion unit 26 uses a photoelectric conversion element that can receive the wavelength of the laser light emitted by the light source 11.

[0039] The power storage units A and B store the power converted by the photoelectric conversion unit 26. That is, the power storage units A and B store the electrical energy converted from the light supplied via the optical fiber 6. For the power storage units A and B, charge / discharge elements such as electric double layer capacitors can be used. In the illustrated example, the child node 2 is assumed to have two systems of power storage units A and B.

[0040] The power storage unit A is a power storage unit for the control unit 27 that controls the entire child node 2. The power storage unit A is connected to the control unit 27, and the electrical energy stored in the power storage unit A serves as a power source for driving the control unit 27. In preparation for a failure, the power storage unit A of this embodiment includes a current power storage unit A1 (first power storage unit) and a backup power storage unit A2 (second power storage unit). A switching unit 40 is disposed between the photoelectric conversion unit 26 and the power storage unit A. The switching unit 40 switches between the power storage units A1 and A2 depending on the optical power of the light source 11 of the parent node 1. The switching unit 40 will be described later.

[0041] The power storage unit B is a power source for operating the device 30. If the influence of transient power consumption that occurs during operation of each device can be reduced or ignored, the two power storage units A and B may be integrated into one power storage unit.

[0042] The control unit 27 is driven by using the electrical energy of the power storage unit A. The control unit 27 analyzes the downstream signal (control signal) received by the receiving unit 24 and executes instructions from the parent node 1. The instructions from the parent node 1 include various instructions such as an instruction to acquire the amount of power stored in the power storage unit A and an instruction to drive the device 30. The control unit 27 may be a microcomputer such as a PIC microcomputer.

[0043] The control unit 27 controls active elements such as the transmitter 25 and the device 30 in accordance with instructions from the parent node 1. For example, the control unit 27 generates an upstream signal by modulating an optical switch provided in the transmitter 25. The upstream signal includes, for example, a response to an instruction from the parent node 1. The control unit 27 may also measure the amount of stored power (voltage) in the power storage units A and B using an AD converter (not shown) or the like, generate an upstream signal including the measured amount of stored power using the transmitter 25, and transmit the signal to the parent node 1.

[0044] The control unit 27 controls the load switch 28 and the voltage boost unit 29 via a control line. The load switch 28 and the voltage boost unit 29 may be driven using electrical energy supplied to the control unit 27 via a control line.

[0045] Load switch 28 is disposed between power storage unit B and device 30, and controls the power supply to device 30 in accordance with instructions from control unit 27. Voltage boost unit 29 is disposed between power storage unit B and device 30, and increases the voltage of the electrical energy supplied from power storage unit B in order to drive device 30.

[0046] The device 30 utilizes the electrical energy of the power storage unit B to operate in accordance with the instructions of the parent node 1 analyzed by the control unit 27. The device 30 may be, for example, a fiber switching device having a function of switching optical fiber fibers for optical fiber communication services, an optical element having a function of monitoring the connection state of the optical fiber 6, or an ICT device (e.g., a sensor) that can be driven with low power.

[0047] 2 shows an example configuration of the switching unit 40 included in the child node 2. The switching unit 40 switches between the power storage units A1 and A2 depending on the optical power of the light source 11 of the parent node 1. Specifically, when the optical power output by the light source 11 exceeds a predetermined value, the switching unit 40 switches the storage destination from the power storage unit A1 to the power storage unit A2, or from the power storage unit A2 to the power storage unit A1. Here, an example will be described where switching from the power storage unit A1 to the power storage unit A2 is performed.

[0048] The illustrated switching unit 40 includes resistors 41A to 41E, a transistor 42, changeover switches 43A and 43B, and a DC power supply element 45.

[0049] The output system of the photoelectric conversion unit 26 branches into two systems, one of which is connected to the power storage unit A1 via a changeover switch 43A, and the other of which is connected to a transistor 42 via resistors 41A, 41B, and 41C.

[0050] The transistor 42 is driven (ON) when the voltage converted according to the optical power of the light source 11 of the parent node 1 exceeds a predetermined voltage value. That is, the driving of the transistor 42 is controlled by the controller 15 changing the optical power of the light source 11. Here, the transistor 42 is driven when the light source 11 outputs optical power greater than normal.

[0051] In the illustrated example, when the output voltage of photoelectric conversion unit 26 reaches a predetermined voltage value higher than normal, the voltage divided by resistors 41A and 41B becomes equal to or higher than the operating voltage of transistor 42. In this case, a base current is input, and a collector current flows from transistor 42 via resistor 41D to selector switches 43A and 43B, operating selector switches 43A and 43B. This allows switching between power storage units A1 and A2.

[0052] An npn junction bipolar transistor or the like may be used as the transistor 42. In this embodiment, the transistor 42 is used, but the present invention is not limited to this, and a contactless switch other than the transistor 42 may also be used.

[0053] Resistor 41C is used to adjust the base current, resistor 41E is used to adjust the emitter current, and resistor 41D is used to adjust the collector current flowing through changeover switches 43A and 43B. Note that if the voltage output from photoelectric conversion unit 26 can be adjusted to an appropriate range that allows transistor 42 to operate, switching unit 40 does not need to include resistors 41A to 41E.

[0054] The selector switches 43A and 43B switch the storage destination from the power storage unit A1 to the power storage unit A2 (or from the power storage unit A2 to the power storage unit A1) by driving the transistor 42. The selector switch 43A switches between the power storage units A1 and A2 that store the power output from the photoelectric conversion unit 26. The selector switch 43B switches between the power storage units A1 and A2 that the control unit 27 is connected to.

[0055] A latching relay may be used for the changeover switches 43A, 43B. That is, the changeover switches 43A, 43B may be equipped with a latching relay. A latching relay is a switch that can maintain the relay contacts in an ON or OFF state by pulse input. The latching relay is operated by the DC power supply element 45 to switch the switch and can maintain the switched state without using power from the DC power supply element 45. Therefore, by using a latching relay, low power consumption can be achieved. For example, a long-life coin-type temporary battery can be used for the DC power supply element 45. Note that other switches may be used as long as they can maintain the switched state without using a power source.

[0056] <Switching Process of Power Storage Unit> Next, the switching process of the power storage unit according to this embodiment will be described.

[0057] In an optical node system, it is not practical to provide child node 2 with a function for monitoring the fault state of power storage unit A1 because this increases the power consumption of child node 2. In other words, providing a monitoring function on the child node 2 side increases the power consumption of child node 2 under normal circumstances.

[0058] On the other hand, if the amount of stored power in the power storage unit A1 of the child node 2 becomes 0, the child node 2 becomes inoperable, so the parent node 1 inquires about the amount of stored power from the child node 2 and controls the power supply. In this embodiment, the inquiry about the amount of stored power made by the parent node 1 is used to detect a failure in the power storage unit A1.

[0059] If the power storage unit fails, the child node 2 becomes inoperable, and therefore does not respond to inquiries from the parent node 1. When the parent node 1 stops responding, it operates the switching unit 40 to charge the spare power storage unit A2, thereby securing the power necessary for the operation of the child node 2 and restoring the child node 2. In this way, in this embodiment, the power storage unit of the child node is switched by remote operation from the parent node. This allows the child node 2 to be restored in a short time and at low cost, without having to dispatch a worker to the location where the child node 2 is located.

[0060] FIG. 3 is a flowchart showing an example of the switching process of the power storage unit A according to this embodiment.

[0061] The parent node 1 (controller 15) transmits a downstream signal to the child node 2 via the optical fiber 6 to inquire about the amount of power stored in the power storage unit A1, and instructs the child node 2 to measure the amount of power stored in the power storage unit A1 (S11). The parent node 1 then waits for a response (upstream signal) from the child node 2 to the inquiry.

[0062] Under normal conditions, when child node 2 receives an inquiry from parent node 1, it measures the amount of power stored in power storage unit A1 and transmits a response including the measured amount of power stored to parent node 1. On the other hand, if power storage unit A1 fails, child node 2 becomes inoperable. Therefore, even if parent node 1 transmits an inquiry to child node 2, there is no response from child node 2.

[0063] If the parent node 1 receives a response from the child node 2 within a predetermined time (S12: YES), it determines that the child node 2 is operating normally, waits until the next inquiry timing, returns to S11, and repeats the process of inquiring about the stored energy amount from the child node 2.

[0064] If no response is received from child node 2 within a predetermined time (S12: NO), parent node 1 determines that power storage unit A1 has failed. Then, parent node 1 outputs an instruction to light source 11 to increase optical power in order to operate switching unit 40 of child node 2 (S13). This causes light source 11 to output stronger optical power than normal. Under normal circumstances, light source 11 outputs normal optical power to supply power to child node 2 and communicate with child node 2.

[0065] In child node 2, upon receiving optical power stronger than normal, switching unit 40 operates, and switching unit 40 switches the storage destination from power storage unit A1 to power storage unit A2 (S14). Specifically, when the voltage input from photoelectric conversion unit 26 becomes higher than a predetermined voltage value, transistor 42 is driven, and a collector current flows to changeover switches 43A and 43B, operating changeover switches 43A and 43B. Changeover switch 43A changes the storage destination of the electrical energy output from photoelectric conversion unit 26 to power storage unit A2, and changeover switch 43B changes the connection destination of control unit 27 to power storage unit A2.

[0066] After the time required for the switching process of child node 2 in S14 has elapsed, the parent node outputs an instruction to light source 11 to return the optical power increased in S13 to normal optical power (S15). As a result, light source 11 outputs light at normal optical power to child node 2. Child node 2 converts the light supplied from parent node 1 into electrical energy and stores it in the switched power storage unit A2. When the amount of stored power in power storage unit A2 reaches the amount required for startup, child node 2 autonomously restarts (S16). That is, when the voltage of power storage unit A2 rises to the value required for startup of control unit 27 and is charged, control unit 27 restarts.

[0067] When a predetermined time has elapsed since the instruction to return to the normal optical power in S15 (S117: YES), the parent node 1 returns to S11 and transmits a downstream signal inquiring about the amount of stored power in the switched power storage unit A2 to the child node 2. This predetermined time is the time until the amount of stored power in the power storage unit A2 reaches the amount necessary to start the control unit 27, and is set in advance.

[0068] 2 , in this embodiment, the switching unit 40 is connected to the photoelectric conversion unit 26, and the transistor 42 is driven by light received by the photoelectric conversion unit 26. However, the present invention is not limited to this. The switching unit 40 may be connected to the receiving unit 24, and the transistor 42 may be driven by light received by the receiving unit 24.

[0069] 4 shows an example configuration of a switching unit 40A included in a child node 2 of Modification 1. The illustrated switching unit 40A includes resistors 41A to 41E, a transistor 42, changeover switches 43A and 43B, and a DC power supply element 45. The switching unit 40A differs from the switching unit 40 in FIG. 2 in that it is connected to a receiving unit 24, but is otherwise similar to the switching unit 40 in FIG. 2. The switching unit 40A switches between power storage units A1 and A2 depending on the optical power of the light source 11 of the parent node 1.

[0070] 4 is branched into two output systems, one of which is connected to the control unit 27 and the other of which is connected to the switching unit 40A. That is, the other of which is connected to a transistor 42 via resistors 41A, 41B, and 41C.

[0071] The transistor 42 is driven (ON) when the voltage converted in accordance with the optical power of the light source 11 exceeds a predetermined voltage value. The transistor 42 is driven when the light source 11 outputs optical power greater than normal.

[0072] In the illustrated example, when the output voltage of photoelectric conversion unit 26 reaches a predetermined voltage value higher than normal, the voltage divided by resistors 41A and 41B becomes equal to or higher than the operating voltage of transistor 42. In this case, a base current is input, and a collector current flows from transistor 42 via resistor 41D to selector switches 43A and 43B, operating selector switches 43A and 43B. This allows switching between power storage units A1 and A2.

[0073] 1, the child node 2 includes one switching unit 40 disposed between the photoelectric conversion unit 26 and the power storage unit A, but is not limited to this. For example, if the power storage unit B has two power storage units B1 and B2 (not shown), one for active use and one for standby use, the child node 2 may include a switching unit 40 for the power storage unit A and another switching unit for the power storage units B1 and B2.

[0074] The other switching unit is disposed between the photoelectric conversion unit 26 and the power storage units B1 and B2, and switches between the power storage units B1 and B2. In this case, the changeover switch 43A of the other switching unit switches between the power storage units B1 and B2 that store the power output from the photoelectric conversion unit 26. The changeover switch 43B switches between the power storage units B1 and B2 that the control unit 27 is connected to.

[0075] Furthermore, when power storage unit A is configured with only one power storage unit and power storage unit B is configured with two power storage units B1 and B2, switching unit 40 may be disposed between photoelectric conversion unit 26 and power storage units B1 and B2. Furthermore, modification 1 and modification 2 may be combined.

[0076] The optical node system of this embodiment described above comprises a parent node 1 and a child node 2. The parent node 1 comprises a light source 11 that outputs light to the child node 2 via an optical fiber 6, and a controller 15 that increases the optical power of the light source 11 and instructs the child node 2 to switch the storage destination. The child node 2 comprises a storage unit A1 and a storage unit A2 that store the power converted from the light, and a switching unit 40 that switches the storage destination from the storage unit A1 to the storage unit A2 when the optical power of the light exceeds a predetermined value.

[0077] In this embodiment, simply by changing the optical power of the light source 11 of the parent node 1, the power storage units A1 and A2 of the child node 2 can be switched over remotely. That is, in response to an instruction from the parent node 1, the failed power storage unit A1 can be switched over to the spare power storage unit A2, thereby ensuring power within the child node 2. Therefore, the function of the child node 2 can be restored in a short time and at low cost without dispatching a worker to the site, thereby enabling the provision of high-quality services.

[0078] Furthermore, in this embodiment, when the parent node 1 detects a poor response from the child node 2, it activates the switching unit 40 of the child node. As a result, in this embodiment, it is possible to switch the power storage unit remotely in a short time and restart the child node 2 without increasing the power consumption of the child node 2 during normal operation.

[0079] The controller 15 of the parent node 1 and the control unit 27 of the child node 2 in the embodiment described above can be, for example, a general-purpose computer system as shown in FIG. 5 . The illustrated computer system includes a CPU (Central Processing Unit, processor) 901, a memory 902, a storage 903 (HDD: Hard Disk Drive, SSD: Solid State Drive), a communication device 904, an input device 905, and an output device 906. The memory 902 and the storage 903 are storage devices. In this computer system, the CPU 901 executes a predetermined program loaded onto the memory 902, thereby realizing the functions of the controller 15 and the control unit 27. For example, the functions of the controller 15 and the control unit 27 are realized by the CPU 901 of the controller 15 executing a program for the controller 15, and by the CPU 901 of the control unit 27 executing a program for the controller 15, respectively.

[0080] The controller 15 and the control unit 27 may be implemented in a single computer or multiple computers. The controller 15 and the control unit 27 may be virtual machines implemented in a computer. The programs of the controller 15 and the control unit 27 may be stored in a computer-readable recording medium such as a HDD, SSD, USB (Universal Serial Bus) memory, CD (Compact Disc), or DVD (Digital Versatile Disc), or may be distributed via a network. The computer-readable recording medium may be, for example, a non-transitory recording medium.

[0081] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the present disclosure.

[0082] 1: Parent node (first node) 11: Light source 12: Modulation unit 13: Receiving unit 14: Optical circulator 15: Controller (control device) 2: Child node (second node) 21, 23: Optical coupler 22: Optical circulator 24: Receiving unit 25: Transmitting unit 26: Photoelectric conversion unit 27: Control unit 28: Load switch 29: Voltage boosting unit 30: Device 40: Switching unit 41A, 41B, 41C, 41D, 41E: Resistor 42: Transistor (contactless switch) 43A, 43B: Changeover switch (latching relay) 45: DC power supply element A, A1, A2, B: Power storage unit (capacitor)

Claims

1. An optical node system comprising a first node and a second node, wherein the first node includes: a light source that outputs light to the second node via an optical fiber; and a control device that increases the optical power of the light source to instruct the second node to switch the power storage destination. The second node includes: a first power storage unit and a second power storage unit in which the power converted from the light is stored; and a switching unit that switches the power storage destination from the first power storage unit to the second power storage unit when the optical power of the light exceeds a predetermined value.

2. The switching unit of the optical node system according to claim 1, comprising: a non-contact switch that is driven when the voltage converted according to the optical power of the light exceeds a predetermined voltage value; and a switching switch that switches the power storage destination from the first power storage unit to the second power storage unit by driving the non-contact switch.

3. The second node of the optical node system according to claim 2 includes a receiving unit that receives a signal superimposed on the light, and the non-contact switch is driven using the light received by the receiving unit.

4. The switching switch of the optical node system according to claim 2 or 3 includes a latching relay.

5. A node driven by optical power supply, comprising: a first power storage unit and a second power storage unit in which the power converted from the light supplied via an optical fiber is stored; and a switching unit that switches the power storage destination from the first power storage unit to the second power storage unit when the optical power of the light exceeds a predetermined value. The switching unit includes: a non-contact switch that is driven when the voltage converted according to the optical power of the light exceeds a predetermined voltage value; and a switching switch that switches the power storage destination from the first power storage unit to the second power storage unit by driving the non-contact switch.

6. A control device for controlling nodes connected via an optical fiber, comprising: a management unit that queries the power storage amount of the power storage unit of the node; and a control unit that increases the optical power of the light source that outputs light to the node via the optical fiber and instructs the node to switch the power storage destination when there is no response to the query.

7. A switching method performed by an optical node system including a first node and a second node, wherein the first node outputs light to the second node via an optical fiber, increases the optical power of the light, and instructs the second node to switch the power storage destination, and the second node includes a first power storage unit and a second power storage unit in which the power converted from the light is stored, and when the optical power of the light exceeds a predetermined value, switches the power storage destination from the first power storage unit to the second power storage unit.

8. A program for causing a computer to function as the control device according to claim 6.

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