JP4909547B2 - Optical switch device, optical access network, system thereof, and optical wavelength division multiplexing transmission method - Google Patents

Description

  The present invention relates to a technique for realizing both unicast, broadcast, and multicast in an optical access network using an optical switch device.

  In Patent Literature 1, one center device (OLT: Optical Line Terminal), a plurality of remote devices (ONU: Optical Network Unit), and one optical switch device (OSM: connected between the OLT and the ONU). A technology related to an optical access network configured in a tree shape with Optical Switching Module) is disclosed.

  Non-Patent Document 1 specifies IEEE 802.3ah (IEEE Standard for Information technology-Telecommunications and information exchange between systems-Local and metropolitan area networks-Specific requirements, June 24, 2004) as a representative of the prior art. PON (Passive Optical Network) exists. This PON transmits an IEEE 802.3ah frame (Ethernet (registered trademark) frame) at a gigabit speed. This prior art will be referred to herein as GE-PON.

  In GE-PON, a wavelength of 1.49 μm band is used in the OLT to ONU direction (downward direction), and a wavelength of 1.31 μm band is used in the ONU to OLT direction (upstream direction), and a WDM (Wavelength Division Multiplexing) system is used. Thus, single-core bidirectional communication is performed using one optical fiber. Furthermore, a conventional three-wavelength division multiplexing system has been devised for transmission of broadcast signals, using 1.55 μm in the downstream direction and adding 1.55 μm to the conventional two wavelengths.

  According to Non-Patent Document 1, in the conventional technology GE-PON, since an optical signal is inevitably branched to all subscribers by using an optical splitter in a transmission line, communication for sending the same signal to all subscribers is performed. Is a suitable method.

Here, an OSM is installed between the OLT and the ONU, and using this OSM, a virtual 1: 1 connection between the OLT and a plurality of ONUs is possible. Communication is called unicast. Communication that sends the same signal to all subscribers is called broadcast. Further, communication in which the same signal is selectively sent to a plurality of subscribers among all subscribers is called multicast.
JP-A-7-177098 IEEE 802.3ah, “IEEE Standard for Information technology-Telecommunications and information exchange between systems-Local and metropolitan area networks-Specific requirements”, June 24, 2004

  However, the conventional example described above has the following problems.

  In an optical access network configured in the form of a tree with one OLT, a plurality of ONUs, and at least one OSM connected between the OLT and the ONU, the OSM has one input port and n output ports. And downstream communication is virtually connected 1: 1.

  When the same signal is transmitted to a plurality of subscribers using this method, a method of copying the signal on the OLT side can be considered, but in this case, it is necessary to copy the packet by the number of subscribers to be transmitted. Yes, it consumes communication bandwidth.

  Therefore, in addition to the function of 1: 1 connection of unicast signals to be sent only to destination subscribers, it is necessary to provide means in the OSM for broadcasting or multicasting signals to be sent to a plurality of subscribers.

  The present invention has been made in view of the circumstances described above, and an object thereof is to simultaneously realize unicast communication and broadcast or multicast in an optical access network.

  In order to solve the above-described problems, the present invention is configured in a tree shape with one center device, a plurality of remote devices, and at least one optical switch device connected between the center device and the remote device. An optical switch device using wavelengths λ1 and λ2 from the center device to the remote device and a wavelength λ3 from the remote device to the center device, the remote device from the center device The wavelength-division multiplexed optical signals having different wavelengths λ1 and λ2 and the optical signal having wavelength λ3 transmitted from the remote device to the center device are separated by wavelength, and at least an optical signal having wavelength λ1 is separated. The first downstream optical switch means is provided by 1 × n first downstream optical switch means having one incoming port and n outgoing ports. The optical signal having the wavelength λ2 is transmitted to only one of the remote devices connected to the n side of the channel means by 1 × n optical signal branching means having one input port and n output ports. The optical signal having the wavelength λ2 is transmitted to n remote devices connected to the n side of the 1 × n optical signal branching means, and the wavelength λ1 is transmitted from the center device to the remote device. And an optical switch device for transmitting an optical signal of wavelength λ3 from the remote device to the center device.

An optical access network according to the present invention is an optical access network in which a center device, a plurality of remote devices, and at least one optical switch device connected between the center device and the remote device are connected in a tree shape by a transmission medium. And
  The center device uses two different wavelengths of light λ1 and λ2 for transmission to the remote device, and the optical switch device unicasts each wavelength λ1 and λ2 used for transmission to the remote device transmitted from the center device. The remote device broadcasts or multicasts, and uses the light of wavelength λ3 different from the wavelengths λ1 and λ2 used for transmission from the center device to the remote device for transmission to the center device. Λ1, λ2, and λ3, which are used for transmission between the remote device and the remote device, are wavelength division multiplexed, and the wavelength division multiplexed light is connected between the center device, the optical switch device, and the remote device. Two different wavelengths λ1 and λ that are wavelength-division multiplexed and transmitted to the remote device from the center device. 1 × n first downstream optical switch means having one input port and n output ports provided in the optical switch device, the optical signal having at least wavelength λ1 is separated by wavelength. Thus, the optical signal having the wavelength λ2 is transmitted to one of the remote devices connected to the n side of the optical switch element. An optical signal having a wavelength of λ2 is transmitted to n remote devices connected to the n side of the 1 × n optical signal branching unit. To do.
  Furthermore, the optical access network of the present invention is an optical access network in which a center device, a plurality of remote devices, and at least one optical switch device connected between the center device and the remote device are connected in a tree shape by a transmission medium. The center device uses two different wavelengths of light λ1 and λ2 for transmission to the remote device, and the optical switch device uses the wavelengths λ1 and λ2 used for transmission to the remote device transmitted from the center device. In addition, the remote device performs unicast, broadcast or multicast, and the remote device uses light having a wavelength λ3 different from the wavelengths λ1 and λ2 used for transmission from the center device to the remote device. And three different λ1, λ2, and λ3 used for transmission between the optical switch device and the remote device. Wavelength division multiplexing of long light is performed, and the wavelength division multiplexed light is transmitted into a transmission medium connected between the center device, the optical switch device, and the remote device, and further transmitted from the center device to the remote device. The optical signals of two different wavelengths λ1 and λ2 that are wavelength-division multiplexed are separated by wavelength, and at least one optical signal of wavelength λ1 has one input port and n output ports provided in the optical switch device. Is transmitted to only one of the remote devices connected to the n side of the optical switch element by the 1 × n first downstream optical switch means having
  The optical signal of wavelength λ2 is branched into m (m ≦ n) by 1 × n second downstream optical switch means having one input port and n output ports provided in the optical switch device. An optical signal having a wavelength λ2 is transmitted to a maximum of m remote devices connected to the n side of the 1 × n first downstream optical switch means.
  Furthermore, the optical access network of the present invention is an optical access network in which a center device, a plurality of remote devices, and at least one optical switch device connected between the center device and the remote device are connected in a tree shape by a transmission medium. The center device uses two different wavelengths of light λ1 and λ2 for transmission to the remote device, and the optical switch device uses the wavelengths λ1 and λ2 used for transmission to the remote device transmitted from the center device. In addition, the remote device performs unicast, broadcast or multicast, and the remote device uses light having a wavelength λ3 different from the wavelengths λ1 and λ2 used for transmission from the center device to the remote device. And three different λ1, λ2, and λ3 used for transmission between the optical switch device and the remote device. Wavelength division multiplexing of long light is performed, and the wavelength division multiplexed light is transmitted in a transmission medium connected between the center device, the optical switch device, and the remote device, and further, a × n maximum from the center device. When transmitting to a remote device, a optical switch device having one input port and n output ports is used, and a center optical device is connected to a optical switch device by a optical fiber. , An optical signal having wavelength λ1 is transmitted to a × n remote devices, and includes optical signal branching means having one input port and a × n output ports in parallel. A signal is transmitted to a × n remote devices.
  Furthermore, the optical access network of the present invention is an optical access network in which a center device, a plurality of remote devices, and at least one optical switch device connected between the center device and the remote device are connected in a tree shape by a transmission medium. The center device uses two different wavelengths of light λ1 and λ2 for transmission to the remote device, and the optical switch device uses the wavelengths λ1 and λ2 used for transmission to the remote device transmitted from the center device. In addition, the remote device performs unicast, broadcast or multicast, and the remote device uses light having a wavelength λ3 different from the wavelengths λ1 and λ2 used for transmission from the center device to the remote device. And three different λ1, λ2, and λ3 used for transmission between the optical switch device and the remote device. The long wavelength light is wavelength division multiplexed, and the wavelength division multiplexed light is transmitted into a transmission medium connected between the center device, the optical switch device, and the remote device, and further, an optical signal of wavelength λ2 from the center device. The control information of the first downstream optical switch means for switching the optical signal of wavelength λ1 having one input port and n output ports provided in the optical switch device is superimposed on the optical switch device. The wavelength sent from the center device to the optical switch device by connecting the input port of the first downstream optical switch means and one output port selected from the control information in accordance with the control information superimposed on the wavelength λ2 The optical signal of λ1 is transmitted to a remote device connected to one output port selected by the control information superimposed on the optical signal of wavelength λ2.

  According to the present invention, it is possible to simultaneously realize unicast communication and broadcast or multicast in an optical access network.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure.

  First, an optical switch device (OSM) according to a first embodiment of the present invention will be described below with reference to FIG.

  The optical switch device (OSM) 31 includes one input / output port connected to the center device (OLT) by the optical fiber 32 and n input / output ports connected to the maximum of n remote devices (ONU) by the optical fiber 33. Have The present embodiment is characterized in that unicast or broadcast is performed for each wavelength (λ1, λ2) of the downstream optical signal wavelength-division multiplexed transmitted from the OLT.

  The demultiplexing / multiplexing unit 1 demultiplexes the wavelength (λ1, λ2) of the downstream optical signal transmitted from the OLT via the optical fiber 32 and supplies the optical signal having the wavelength λ1 for unicast to the optical splitter 3. Then, the optical signal having the wavelength λ 2 for broadcasting is input to the input port of the optical splitter 8. Further, the demultiplexing / multiplexing unit 1 multiplexes the optical signal of the upstream wavelength λ3 from the optical splitter 7, and inputs the upstream optical signal to the optical fiber 32 connected to the OLT.

  There are n demultiplexing / multiplexing units 2, and each is connected to a maximum of n ONUs via optical fibers 33. The demultiplexing / combining unit 2 multiplexes the optical signal having the downstream wavelength λ1 from the output port of the downstream optical switch element 5 and the optical signal having the downstream wavelength λ2 from the output port of the downstream optical splitter 8. To the optical fiber 33 connected to. The demultiplexing / multiplexing unit 2 demultiplexes the upstream optical signal having the wavelength λ3 from the ONU and inputs the upstream optical signal to the input port of the upstream optical switch element 6.

  The optical splitter 3 branches the optical signal of the wavelength λ1 for unicast from the demultiplexing / multiplexing unit 1 into two, and inputs one into the delay unit 4 and the other into the photoelectric conversion unit 11.

  The delay unit 4 delays the optical signal from the optical splitter 3 by a time required for processing an electrical signal, which will be described later, including the time required for the photoelectric conversion unit 11, and then inputs the delayed signal to the downstream optical switch element 5. .

  The downstream optical switch element 5 has one input port and n output ports. The downstream optical signal from the delay unit 4 is transmitted as an input port in units of packets in accordance with an instruction from the optical switch control unit 9. Connect the outgoing port. The optical signal from the output port of the downstream optical switch element is input to the demultiplexing / multiplexing unit 2.

  The optical splitter 8 has one input port and n output ports, and distributes and outputs the optical signal of the wavelength λ2 for broadcasting from the demultiplexing / multiplexing unit 1 to all output ports. The optical signal from the output port of the optical splitter 8 is input to the demultiplexing / multiplexing unit 2.

  The upstream optical switch element 6 is an optical switch element having n input ports and one output port. The upstream optical switch element 6 transmits an optical signal having an upstream wavelength λ3 from the demultiplexing / multiplexing unit 2 to the optical switch control unit 9. Connect the incoming and outgoing ports in packet units according to the instructions. The optical signal from the output port of the upstream optical switch element 6 is input to the optical splitter 7.

  The photoelectric conversion unit 11 converts the optical signal from the optical splitter 3 into an electrical signal and inputs the electrical signal to the optical switch control unit 9.

  The optical switch control unit 9 performs the following processing.

  (9-1) The optical switch control unit receives the electrical signal from the photoelectric conversion unit 11, determines the ONU that is the destination of the downstream packet, and outputs the downstream optical switch element 5 that is connected to the ONU that is the destination. A control signal for connecting the port and the input port is input to the downstream optical switch element 5.

  (9-2) The optical switch control unit 9 acquires the control information of the upstream optical switch element 6 from the downstream packet, and connects the outgoing port and the incoming port of the upstream optical switch element 6 based on the acquired control information Is input to the upstream optical switch element 6.

  (9-3) The optical switch control unit 9 inputs an electrical signal to the electro-optical conversion unit 20 in order to transmit control information to the OLT. The electro-optical conversion unit 20 converts the input electric signal into an optical signal and inputs the optical signal to the optical splitter 7. The optical splitter 7 inputs a signal from the electro-optical conversion unit 20 to the demultiplexing / multiplexing unit 1.

  Next, the center apparatus (OLT) in the present embodiment will be described below with reference to FIG.

  The center device (OLT) has one input / output port connected to the optical switch device (OSM) by the optical fiber 32.

  The electro-optical conversion unit 26 converts the unicast electric signal input from the downlink unicast signal transmission unit 22 into an optical signal having a wavelength λ 1 for unicast, and inputs the optical signal to the demultiplexing / multiplexing unit 25.

  The electro-optic conversion unit 27 converts the broadcast electrical signal input from the downlink broadcast signal transmission unit into an optical signal having a wavelength λ 2 for broadcasting, and inputs the optical signal to the demultiplexing / multiplexing unit 25.

  The demultiplexing / multiplexing unit 25 multiplexes the wavelengths λ1 and λ2 of the downstream optical signal transmitted to the OSM and inputs them to the optical fiber 32.

  Further, the demultiplexing / multiplexing unit 25 demultiplexes the optical signal having the upstream wavelength λ 3 from the OSM and inputs the demultiplexed optical signal to the photoelectric conversion unit 28. The photoelectric conversion unit 28 converts the optical signal having the upstream wavelength λ3 into electricity and inputs the electrical signal to the upstream signal reception unit 24.

  The broadcast signal can be replaced with a multicast signal.

  Furthermore, the wavelength of λ1 used for unicasting is 1.49 μm, which is the conventional downstream wavelength in GE-PON, and the wavelength of λ2 used for broadcasting or multicasting is the wavelength for broadcasting in GE-PON. The upstream wavelength may be 1.31 μm, which is a conventional upstream wavelength in GE-PON.

  Next, the physical interface unit of the remote unit (ONU) in the present embodiment will be described below with reference to FIG.

  The ONU has one input / output port connected to the optical switch device (OSM) by the optical fiber 33.

  The demultiplexing / multiplexing unit 45 demultiplexes the wavelengths λ1 and λ2 of the downstream optical signal from the OSM, and divides them into an optical signal of wavelength λ1 for unicast and an optical signal of wavelength λ2 for broadcasting. Further, the optical signal having the wavelength λ 3 that goes up to the OSM is multiplexed and input to the optical fiber 33.

  The photoelectric conversion unit 46 converts the input optical signal having the wavelength λ1 for unicast into an electrical signal and inputs the electrical signal to the downlink unicast signal reception unit 42.

  The photoelectric conversion unit 47 converts the input optical signal with the wavelength λ2 for broadcasting into an electrical signal and inputs the electrical signal to the downlink broadcast signal reception unit 43.

  The upstream electrical signal from the ONU is input from the upstream signal transmission unit 44 to the electro-optical conversion unit 48, and when converted to an optical signal having the upstream wavelength λ3, is input to the demultiplexing / multiplexing unit 45.

  The broadcast signal can be replaced with a multicast signal.

  Next, the flow of transmission processing in the present embodiment will be described.

  The center device (OLT) uses light of two different wavelengths (λ1, λ2) for downlink. The light of wavelength λ1 is used for transmission of a unicast signal to be transmitted to one destination ONU among a plurality of remote units (ONUs).

  The light of the other wavelength λ2 is used for transmission of a broadcast signal to be transmitted to all ONUs. A unicast signal and a broadcast signal are wavelength division multiplexed and transmitted from the OLT to the optical switch device (OSM) through a single-core optical fiber.

  When receiving an optical signal wavelength-division multiplexed from the OLT in the OSM, the optical signal is demultiplexed into wavelengths λ1 and λ2.

  After demultiplexing, the optical signal having the wavelength λ1 for unicasting is determined for each packet by the optical switch element, and unicasted to one ONU serving as the destination.

  The optical signal of wavelength λ2 for broadcasting is physically distributed to all ONUs by an optical splitter.

  In the output port of the optical switch element and the output port of the optical splitter, those having the same ONU as the connection destination are connected, and wavelength division multiplexing is performed in units of ONUs.

  An optical signal wavelength-division multiplexed to each ONU is transmitted from the OSM via an optical fiber.

  When the ONU receives the wavelength division multiplexed optical signal from the OSM, the ONU demultiplexes the signals into wavelengths λ1 and λ2, and receives the unicast signal and the broadcast signal separately.

  Note that the wavelength to be multiplexed for downlink does not have to be two waves, and optical signals of three or more waves for downlink may be wavelength division multiplexed. In this case, in the OSM, a means for demultiplexing the multiplexed wavelengths is provided on the OLT side, and a means for multiplexing the demultiplexed wavelengths again in units of ONUs on the ONU side.

  An optical switch element or an optical splitter can be selected depending on whether a signal transmitted with light of each wavelength is unicast, broadcast, or multicast.

  In addition, when light having a broadcast wavelength is distributed to all ONUs by the optical splitter in the OSM, the optical power is lost according to the number of branches of the optical splitter. The loss of optical power due to the optical splitter depends on the light branching itself and cannot be avoided. Therefore, an optical amplifier is provided in the OLT or OSM, the transmission distance is extended by compensating for the loss of optical power by the optical splitter, the number of branches is increased, and the transmission distance and the number of distribution of the optical signal broadcast by the optical splitter are increased. May be.

  Next, an optical switch device (OSM) according to a second embodiment of the present invention will be described below with reference to FIG.

  The optical switch device (OSM) 31 includes one input / output port connected to the center device (OLT) by the optical fiber 32 and n input / output ports connected to a maximum of n remote devices (ONU) by the optical fiber. Have. The present embodiment is characterized in that a wavelength division multiplexed downstream optical signal sent from the OLT is unicast or multicast for each wavelength (λ1, λ2).

  The demultiplexing / multiplexing unit 1 demultiplexes the wavelength (λ1, λ2) of the downstream optical signal transmitted from the OLT via the optical fiber 32 and supplies the optical signal having the wavelength λ1 for unicast to the optical splitter 3. Then, the optical signal of wavelength λ 2 for multicast is input to the input port of the optical switch element 8. Further, the demultiplexing / multiplexing unit 1 multiplexes the optical signal of the upstream wavelength λ3 from the optical splitter 7 and inputs the upstream optical signal to the optical fiber 32 connected to the OLT.

  There are n demultiplexing / multiplexing units 2, and each is connected to a maximum of n ONUs via optical fibers 33. The demultiplexing / multiplexing unit 2 combines the optical signal having the downstream wavelength λ1 from the output port of the downstream optical switch element 5 and the optical signal having the downstream wavelength λ2 from the output port of another downstream optical switch element 8. And input to the optical fiber 33 connected to the ONU. The demultiplexing / multiplexing unit 2 demultiplexes the upstream optical signal having the wavelength λ3 from the ONU and inputs the upstream optical signal to the input port of the upstream optical switch element 6.

  The optical splitter 3 branches the optical signal of the wavelength λ1 for unicast from the demultiplexing / multiplexing unit 1 into two, and inputs one into the delay unit 4 and the other into the photoelectric conversion unit 11.

  The delay unit 4 delays the optical signal from the optical splitter 3 by a time required for processing an electrical signal, which will be described later, including the time required for the photoelectric conversion unit 11, and then inputs the delayed signal to the downstream optical switch element 5. .

  The downstream optical switch element 5 has one input port and n output ports. The downstream optical signal from the delay unit 4 is transmitted as an input port in units of packets in accordance with an instruction from the optical switch control unit 9. Connect the outgoing port. The optical signal from the output port of the downstream optical switch element is input to the demultiplexing / multiplexing unit 2.

  The downstream optical switch element 10 has one input port and n output ports, and transmits an optical signal having a wavelength λ2 for multicast from the demultiplexing / multiplexing unit 1 according to an instruction from the optical switch control unit 9. Distribute to one or more output ports and output. An optical signal from the output port of the optical switch element 8 is input to the demultiplexing / multiplexing unit 2.

  The upstream optical switch element 6 is an optical switch element having n input ports and one output port. The upstream optical switch element 6 transmits an optical signal having an upstream wavelength λ3 from the demultiplexing / multiplexing unit 2 to the optical switch control unit 9. Connect the incoming and outgoing ports in packet units according to the instructions. The optical signal from the output port of the upstream optical switch element 6 is input to the optical splitter 7.

  The photoelectric conversion unit 11 converts the optical signal from the optical splitter 3 into an electrical signal and inputs the electrical signal to the optical switch control unit 9.

  The optical switch control unit 9 performs the following processing.

  (9-1) The optical switch control unit 9 receives the electrical signal from the photoelectric conversion unit 11, determines the ONU that is the destination of the downstream packet, and the downstream optical switch element 5 that is connected to the ONU that is the destination. A control signal for connecting the output port and the input port is input to the downstream optical switch element 5.

  (9-2) The optical switch control unit 9 acquires control information of the upstream optical switch element 6 from the downstream packet, and connects the outgoing port and the incoming port of the upstream optical switch element 6 based on the acquired control information. A signal is input to the upstream optical switch element 6.

  (9-3) The optical switch control unit 9 acquires control information of the downstream optical switch element 8 from the downstream packet, and based on the acquired control information, at least one or more outgoing ports among the maximum of n outgoing ports A control signal for selecting is input to another downstream optical switch element 8.

  (9-4) The optical switch control unit 9 inputs an electrical signal to the photoelectric conversion unit 20 in order to transmit control information to the OLT. The photoelectric conversion unit 20 converts the input electrical signal into an optical signal and inputs the optical signal to the optical splitter 7. The optical splitter 7 inputs a signal from the photoelectric conversion unit 20 to the demultiplexing / multiplexing unit 1.

  Next, the flow of transmission processing in the present embodiment will be described.

  The center device (OLT) uses light of two different wavelengths (λ1, λ2) for downlink. The light of wavelength λ1 is used for transmission of a unicast signal transmitted to one destination ONU among a plurality of remote units (ONUs).

  The light of the other wavelength λ2 is used for transmission of a multicast signal to be transmitted to at least one ONU. A unicast signal and a multicast signal are wavelength division multiplexed and transmitted from the OLT to the optical switch device (OSM) through a single-core optical fiber.

  When receiving an optical signal wavelength-division multiplexed from the OLT in the OSM, the optical signal is demultiplexed into wavelengths λ1 and λ2.

  After demultiplexing, the optical signal having the wavelength λ1 for unicasting is determined for each packet by the downstream optical switch element 5, and is unicast to one remote device (ONU) serving as the destination.

  The optical signal having the wavelength λ 2 for multicast is selectively distributed to at least one ONU by the downstream optical switch element 10.

  In the outgoing port of the downstream optical switch element 5 for unicast and the outgoing port of the downstream optical switch element 10 for multicast, those having the same ONU as the connection destination are connected and wavelength division multiplexed in units of ONUs.

  An optical signal wavelength-division multiplexed to each ONU is transmitted from the OSM via an optical fiber.

  When receiving the wavelength division multiplexed optical signal from the OSM, the ONU demultiplexes the signals into wavelengths λ1 and λ2, and receives the unicast signal and the multicast signal separately.

  In addition, it is possible to make it equivalent to broadcast by setting the transmission target of the multicast signal to all ONUs. Similarly, by setting the transmission target of a multicast signal to one ONU, it is possible to make it equivalent to unicast.

  Next, the configuration of the optical switch device according to the third embodiment of the present invention will be described below with reference to FIG.

  The optical switch device has a basic configuration of a functional unit that performs unicast communication in the upstream and downstream directions. This is called a basic optical switch 51. The function unit having means for realizing broadcast or multicast communication can be increased or decreased according to use conditions. This is called an additional optical switch device 52.

  Between the basic optical switch device 51 and the additional optical switch device 52, an optical signal connection unit 55 for inputting an optical signal having a wavelength used for broadcast and multicast from the basic optical switch device 51 is provided. In addition, an electrical signal connection unit 56 for inputting and outputting electrical signals for controlling broadcast and multicast communications is provided. Furthermore, the optical signal junction part 57 which inputs the optical signal branched by the optical change part 53 from an extension optical switch apparatus into a basic optical switch apparatus again is provided.

  The extension optical switch device 52 includes an optical changing unit 53 that branches an optical signal under the control of the optical signal branching means control unit 54. The optical signal branching means control unit 54 obtains control information through the electrical signal control unit 56 by the optical switch control unit 9 in the basic optical switch device 51. The light changing unit 53 can select an optical splitter or an optical switch element according to usage conditions.

  When there is a situation where it is technically difficult or expensive to increase the number of optical switches, a system configuration may be used in which a plurality of optical switch elements with a small number of output ports and a multi-port optical splitter are used in combination. .

  Next, the configuration of the optical switch device according to the fourth embodiment of the present invention will be described below with reference to FIG.

  Corresponding to the legacy GE-PON system, by using only one optical switch element 8 instead of the optical switch element 5 shown in FIG. Realize.

  The optical switch element 8 can select one or more arbitrary output ports from among a plurality of output ports under the control of the optical switch control unit 9 and output an input signal to the selected output port.

  If the signal from the OLT is unicast, select a single outgoing port as the destination, select multiple arbitrary outgoing ports if multicast, and select all outgoing ports if broadcast. Unicast, broadcast, and multicast can be physically realized at one wavelength.

  According to the present embodiment, it is possible to cope with a legacy GE-PON system in which only one wavelength can be used in the downstream, and unicast and broadcast or multicast can be realized with one wavelength.

  Each of the above-described embodiments is a preferred embodiment of the present invention, and various modifications can be made without departing from the scope of the present invention. For example, the processing for realizing the function of each device may be performed by causing each device to read and execute a program for realizing the functions of the OLT, ONU, and OSM in the above embodiment. Further, the program is transmitted to another computer system by a transmission wave via a computer-readable recording medium such as a CD-ROM or a magneto-optical disk, or via a transmission medium such as the Internet or a telephone line. Also good.

It is a schematic block diagram of the optical switch apparatus (OSM) in the 1st Embodiment of this invention. It is a schematic block diagram of the center apparatus (OLT) in the 1st Embodiment of this invention. It is a schematic block diagram of the remote apparatus (ONU) in the 1st Embodiment of this invention. It is a schematic block diagram of the optical switch apparatus (OSM) in the 2nd Embodiment of this invention. It is a schematic block diagram of the optical switch apparatus (OSM) in the 3rd Embodiment of this invention. It is a schematic block diagram of the optical switch apparatus (OSM) in the 4th Embodiment of this invention.

Explanation of symbols

1, 2, 25, 45 Demultiplexing and multiplexing unit 3 Optical splitter 4 Delay unit 5, 10 Downstream optical switch element 6 Upstream optical switch element 7, 8 Optical splitter 9 Optical switch control unit 11, 28, 46, 47 Photoelectricity Conversion unit 20, 26, 27, 48 Electro-optical conversion unit 21 Center device (OLT)
22 Downlink Unicast Signal Transmitter 23 Downlink Broadcast Signal Transmitter 24 Uplink Signal Receiver 31 Optical Switch Device (OSM)
32, 33 Optical fiber 41 Remote unit (ONU)
42 downlink unicast signal receiver 43 downlink broadcast signal receiver 44 uplink signal transmitter 51 basic optical switch device 52 additional optical switch device 53 optical change unit 54 optical signal branching means controller 55 optical signal connection unit 56 electrical signal connection unit 57 Optical signal connection

Claims (16)

In an optical access network configured in a tree shape by one center device, a plurality of remote devices, and at least one optical switch device connected between the center device and the remote device, An optical switch device using wavelengths λ1 and λ2 for the device and a wavelength λ3 from the remote device to the center device,
The wavelength-division multiplexed optical signals of two wavelengths λ1 and λ2 transmitted from the center device to the remote device and the optical signal of wavelength λ3 transmitted from the remote device to the center device are separated by wavelength. ,
An optical signal of at least wavelength λ1 is connected to the n side of the first downstream optical switch means by 1 × n first downstream optical switch means having one input port and n output ports. Transmit only to one of the remote devices;
An optical signal of wavelength λ2 is branched into n by 1 × n optical signal branching means having one input port and n output ports, and connected to the n side of the 1 × n optical signal branching means. transmitting the optical signal of the wavelength λ2 to the n remote devices;
An optical switch device that transmits optical signals of wavelengths λ1 and λ2 from the center device to the remote device, and transmits an optical signal of wavelength λ3 from the remote device to the center device. An optical switch device in an optical access network configured in a tree shape with one center device, a plurality of remote devices, and at least one optical switch device connected between the center device and the remote device,
Two-wavelength division multiplexed downstream optical signals transmitted by a transmission medium connected to the center apparatus side are demultiplexed for each wavelength, and upstream optical signals are transmitted by a transmission medium connected to the center apparatus side. Means for multiplexing the wavelength of the downstream optical signal;
Means for branching the optical signal of one wavelength λ1 into two of the downstream optical signals of two wavelengths demultiplexed by the means for multiplexing;
A means for giving a delay to the optical signal having one wavelength λ1 of the branched optical signals having the wavelength λ1,
Means for converting the branched optical signal of the other wavelength λ1 into an electrical signal;
The downstream packet is extracted from the optical signal having the wavelength λ1 that has been electrically converted, the control information of the upstream optical switch means and the first downstream optical switch means is obtained from the extracted downstream packet, and based on the acquired control information Means for controlling the upstream optical switch means and the first downstream optical switch means;
A first downstream optical switch means having one input port and n output ports for optically switching an optical signal of wavelength λ1 from the delay providing means;
An optical signal branching means having one input port for branching the optical signal of the other wavelength λ2 among the downstream optical signals having two wavelengths branched by the means for multiplexing, and n output ports;
Of the n output ports from the means for converting to the electrical signal and the optical signal branching means, the remote device that is the connection destination combines the optical signal of wavelength λ1 and the optical signal of wavelength λ2, and connects Comprising n means for demultiplexing the optical signal of wavelength λ3 from the remote device,
In the transmission medium connected to the remote device side of the own device, the optical signal of wavelength λ2 and the optical signal of wavelength λ2 are multiplexed and the optical signal of wavelength λ3 is demultiplexed from the remote device that is the connection destination. An optical switch device for transmitting a wavelength division multiplexed downstream optical signal from the means to a remote device. In an optical access network configured in a tree shape by one center device, a plurality of remote devices, and at least one optical switch device connected between the center device and the remote device, An optical switch device using wavelengths λ1 and λ2 for the device and a wavelength λ3 from the remote device to the center device,
Wavelength division multiplexed optical signals of two different wavelengths λ1 and λ2 transmitted from the center device to the remote device are separated by wavelength,
An optical signal of at least wavelength λ1 is connected to the n side of the first downstream optical switch means by 1 × n first downstream optical switch means having one input port and n output ports. Transmit only to one of the remote devices;
An optical signal of wavelength λ2 is branched into m (m ≦ n) by 1 × n second downstream optical switch means having one input port and n output ports, and the 1 × n first signal Transmitting the optical signal having the wavelength λ2 to a maximum of m remote devices connected to the n side of the downstream optical switch means,
An optical switch device that transmits optical signals of wavelengths λ1 and λ2 from the center device to the remote device, and transmits an optical signal of wavelength λ3 from the remote device to the center device. The second downstream optical switch means includes means for selecting at least one outgoing port according to the content of the optical signal of wavelength λ2 from the center device;
4. The optical switch device according to claim 3, wherein at least one output port to be selected is changed in response to a change in the content of the optical signal having the wavelength λ2 from the center device. An optical switch device in an optical access network configured in a tree shape with one center device, a plurality of remote devices, and at least one optical switch device connected between the center device and the remote device,
Two-wavelength division multiplexed downstream optical signals transmitted by a transmission medium connected to the center apparatus side are demultiplexed for each wavelength, and upstream optical signals are transmitted by a transmission medium connected to the center apparatus side. Means for multiplexing the wavelength of the downstream optical signal;
Means for branching the optical signal of one wavelength λ1 into two of the downstream optical signals of two wavelengths demultiplexed by the means for multiplexing;
A means for giving a delay to the optical signal having one wavelength λ1 of the branched optical signals having the wavelength λ1,
Means for converting the branched optical signal of the other wavelength λ1 into an electrical signal;
The downstream packet is extracted from the optical signal having the wavelength λ1 that has been electrically converted, the control information of the upstream optical switch means and the first downstream optical switch means is obtained from the extracted downstream packet, and based on the acquired control information Means for controlling the upstream optical switch means and the first downstream optical switch means;
A first downstream optical switch means having one input port and n output ports for optically switching an optical signal of wavelength λ1 from the delay providing means;
A second downstream optical switch having one incoming port and n outgoing ports for branching the optical signal having the other wavelength λ2 among the downstream optical signals having two wavelengths branched by the means for multiplexing. Means,
Of the n output ports from the first downstream optical switch means and the second downstream optical switch means, the optical signal having the wavelength λ1 and the optical signal having the wavelength λ2 that are the same as the remote device to which the connection is made And n means for demultiplexing the optical signal of wavelength λ3 from the remote device that is the connection destination,
The second downstream optical switch means has a function of selectively outputting an optical signal from at least one of the n output ports, and a transmission medium connected to the remote device side of the own device Then, the optical signal having the wavelength λ1 and the optical signal having the wavelength λ2 are multiplexed and the wavelength-division multiplexed downstream optical signal from the means for demultiplexing the optical signal having the wavelength λ3 from the remote device that is the connection destination Is transmitted to a remote device. When only one wavelength λ1 is used for transmission from the center device to the remote device,
Physically separating the optical signal branching means of wavelength λ2 or the second downstream optical switch means from the optical switch device;
When two wavelengths λ1 and λ2 are used for transmission from the center device to the remote device, the optical signal branching means or the second downstream optical switch means of wavelength λ2 is coupled to the optical switch device,
6. The optical switch device according to claim 1, wherein the optical signal branching unit having the wavelength [lambda] 2 or the second downstream optical switch unit is separated and coupled according to wavelength multiplexing conditions. . A first optical signal of wavelength λ1 having one input port and n output ports provided in the optical switch device according to claim 3 is switched to an optical signal of wavelength λ2 from the center device. Superimposing control information of the optical switch means downstream of
  The optical switch device connects an input port of the first downstream optical switch means and one output port selected from the control information according to the control information superimposed on the wavelength λ2,
  The optical signal of wavelength λ1 sent from the center device to the optical switch device is transmitted to the remote device connected to one output port selected by the control information superimposed on the optical signal of wavelength λ2. An optical wavelength division multiplexing transmission method. Means for selecting at least one outgoing port for the second downstream optical switch means in the optical switch device;
  According to the content of the optical signal of wavelength λ2 from the center device, m output ports (1 ≦ m ≦ n) are connected,
  8. The optical wavelength division multiplexing transmission method according to claim 7, wherein one-to-one connection and one-to-many connection are switched.   An optical access network in which a center device, a plurality of remote devices, and at least one optical switch device connected between the center device and the remote device are connected in a tree shape by a transmission medium,
  The center device uses two different wavelengths of light λ1 and λ2 for transmission to the remote device,
  The optical switch device performs unicast, broadcast or multicast for each of the wavelengths λ1 and λ2 used for transmission from the center device to the remote device,
  The remote device uses light of a wavelength λ3 different from the light of wavelengths λ1 and λ2 used for transmission from the center device to the remote device for transmission to the center device,
  Wavelength-division-multiplexed light of three different wavelengths λ1, λ2, and λ3 used for transmission between the center device, the optical switch device, and the remote device,
  The wavelength division multiplexed light is transmitted in a transmission medium connected between the center device, the optical switch device, and the remote device,
  further,
  Wavelength division multiplexed optical signals of two different wavelengths λ1 and λ2 transmitted from the center device to the remote device are separated by wavelength,
  An optical signal of at least wavelength λ1 is transmitted to the n side of the optical switch element by 1 × n first downstream optical switch means having one input port and n output ports provided in the optical switch device. Transmitted to only one of the connected remote devices;
  The optical signal of wavelength λ2 is branched into n by 1 × n optical signal branching means having one input port and n output ports provided in the optical switch device,
  An optical access network, wherein an optical signal having the wavelength λ2 is transmitted to n remote devices connected to the n side of the 1 × n optical signal branching means. An optical access network in which a center device, a plurality of remote devices, and at least one optical switch device connected between the center device and the remote device are connected in a tree shape by a transmission medium,
  The center device uses two different wavelengths of light λ1 and λ2 for transmission to the remote device,
  The optical switch device performs unicast, broadcast or multicast for each of the wavelengths λ1 and λ2 used for transmission from the center device to the remote device,
  The remote device uses light of a wavelength λ3 different from the light of wavelengths λ1 and λ2 used for transmission from the center device to the remote device for transmission to the center device,
  Wavelength-division-multiplexed light of three different wavelengths λ1, λ2, and λ3 used for transmission between the center device, the optical switch device, and the remote device,
  The wavelength division multiplexed light is transmitted in a transmission medium connected between the center device, the optical switch device, and the remote device,
further,
  Wavelength division multiplexed optical signals of two different wavelengths λ1 and λ2 transmitted from the center device to the remote device are separated by wavelength,
  An optical signal of at least wavelength λ1 is transmitted to the n side of the optical switch element by 1 × n first downstream optical switch means having one input port and n output ports provided in the optical switch device. Transmitted to only one of the connected remote devices;
  The optical signal of wavelength λ2 is branched into m (m ≦ n) by 1 × n second downstream optical switch means having one input port and n output ports provided in the optical switch device. And
  An optical access network, wherein an optical signal having the wavelength λ2 is transmitted to a maximum of m remote devices connected to the n side of the 1 × n first downstream optical switch means. In accordance with the content of the optical signal of wavelength λ2 from the center device, the second downstream optical switch means provided in the optical switch device comprises means for selecting at least one outgoing port,
  11. The optical access network according to claim 10, wherein at least one or more output ports to be selected are changed in response to a change in the content of the optical signal having the wavelength λ2 from the center device. An optical access network in which a center device, a plurality of remote devices, and at least one optical switch device connected between the center device and the remote device are connected in a tree shape by a transmission medium,
  The center device uses two different wavelengths of light λ1 and λ2 for transmission to the remote device,
  The optical switch device performs unicast, broadcast or multicast for each of the wavelengths λ1 and λ2 used for transmission from the center device to the remote device,
  The remote device uses light of a wavelength λ3 different from the light of wavelengths λ1 and λ2 used for transmission from the center device to the remote device for transmission to the center device,
  Wavelength-division-multiplexed light of three different wavelengths λ1, λ2, and λ3 used for transmission between the center device, the optical switch device, and the remote device,
  The wavelength division multiplexed light is transmitted in a transmission medium connected between the center device, the optical switch device, and the remote device,
further,
  When transmitting from the center device to a × n remote devices at the maximum, a number of the optical switch devices each having one input port and n output ports are used, and a number from the center device. A number of the optical switch devices are connected by an optical fiber, and an optical signal of wavelength λ1 is transmitted to the a × n number of remote devices,
  An optical signal branching means having one input port and a × n output ports in parallel is provided, and an optical signal having a wavelength λ2 from the center device is transmitted to a × n remote devices. Optical access network. When transmitting from the center device to a × n remote devices at the maximum, a number of the optical switch devices each having one input port and n output ports are used, and a number from the center device. A number of the optical switch devices are connected by an optical fiber, and an optical signal of wavelength λ1 is transmitted to the a × n number of remote devices,
  An optical signal branching means having one input port and a × n output ports in parallel is provided, and an optical signal having a wavelength λ2 from the center device is transmitted to a × n remote devices. The optical access network according to any one of claims 9 to 11. An optical access network in which a center device, a plurality of remote devices, and at least one optical switch device connected between the center device and the remote device are connected in a tree shape by a transmission medium,
  The center device uses two different wavelengths of light λ1 and λ2 for transmission to the remote device,
  The optical switch device performs unicast, broadcast or multicast for each of the wavelengths λ1 and λ2 used for transmission from the center device to the remote device,
  The remote device uses light of a wavelength λ3 different from the light of wavelengths λ1 and λ2 used for transmission from the center device to the remote device for transmission to the center device,
  Wavelength-division-multiplexed light of three different wavelengths λ1, λ2, and λ3 used for transmission between the center device, the optical switch device, and the remote device,
  The wavelength division multiplexed light is transmitted in a transmission medium connected between the center device, the optical switch device, and the remote device,
further,
  The first downstream light that switches the optical signal of wavelength λ1 having the one input port and n output ports provided in the optical switch device to the optical signal of wavelength λ2 from the center device Superimposing the control information of the switch means,
  The optical switch device connects an input port of the first downstream optical switch means and one output port selected from the control information according to the control information superimposed on the wavelength λ2,
  The optical signal of wavelength λ1 sent from the center device to the optical switch device is transmitted to the remote device connected to one output port selected by the control information superimposed on the optical signal of wavelength λ2. A featured optical access network. The first downstream light that switches the optical signal of wavelength λ1 having the one input port and n output ports provided in the optical switch device to the optical signal of wavelength λ2 from the center device Superimposing the control information of the switch means,
The optical switch device connects an input port of the first downstream optical switch means and one output port selected from the control information according to the control information superimposed on the wavelength λ2,
The optical signal of wavelength λ1 sent from the center device to the optical switch device is transmitted to the remote device connected to one output port selected by the control information superimposed on the optical signal of wavelength λ2. The optical access network according to any one of claims 9 to 13 , Means for selecting at least one outgoing port for the second downstream optical switch means in the optical switch device;
According to the content of the optical signal having the wavelength λ2 from the center device, m output ports (1 ≦ m ≦ n) are connected,
The optical access network according to any one of claims 10, 11, 14 , and 15 , wherein one-to-one connection and one-to-many connection are switched.

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