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WO2004010612A1 - Procede et systeme de transmission optique - Google Patents

Procede et systeme de transmission optique Download PDF

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Publication number
WO2004010612A1
WO2004010612A1 PCT/JP2002/007427 JP0207427W WO2004010612A1 WO 2004010612 A1 WO2004010612 A1 WO 2004010612A1 JP 0207427 W JP0207427 W JP 0207427W WO 2004010612 A1 WO2004010612 A1 WO 2004010612A1
Authority
WO
WIPO (PCT)
Prior art keywords
transmission circuit
optical
station
home
circuit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2002/007427
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English (en)
Japanese (ja)
Inventor
Kazumitsu Maki
Haruo Yamashita
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fujitsu Ltd
Original Assignee
Fujitsu Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fujitsu Ltd filed Critical Fujitsu Ltd
Priority to PCT/JP2002/007427 priority Critical patent/WO2004010612A1/fr
Priority to JP2004522705A priority patent/JP4044558B2/ja
Publication of WO2004010612A1 publication Critical patent/WO2004010612A1/fr
Anticipated expiration legal-status Critical
Priority to US11/039,916 priority patent/US20050123293A1/en
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/40—Transceivers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
    • H04B10/077—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using a supervisory or additional signal
    • H04B10/0771—Fault location on the transmission path
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B2210/00—Indexing scheme relating to optical transmission systems
    • H04B2210/07—Monitoring an optical transmission system using a supervisory signal
    • H04B2210/078—Monitoring an optical transmission system using a supervisory signal using a separate wavelength

Definitions

  • the present invention relates to an optical transmission system, and more particularly to a bidirectional optical transmission method and system using the same wavelength using a single-core optical fiber.
  • WDM wavelength division multiplexing
  • bidirectional transmission can be performed using a single-core optical fiber because of the large number.
  • a single-core bidirectional optical transmission system there is a WDM bidirectional transmission system that uses different wavelengths for upstream and downstream.However, it is necessary to prepare light-emitting elements with different wavelengths, and it depends on the wavelength division multiplexer. There is an economic limit, such as the need to have the property.
  • wavelength is the same valuable resource as radio waves, it is desirable that one service can be transmitted bidirectionally with one wavelength.
  • Such single-wavelength bidirectional transmission systems with the same wavelength include a time-axis compression multiplexed bidirectional optical transmission system and an echo canceller bidirectional optical transmission system, both of which operate on the same principle as the case of metallic transmission. .
  • the station-side transmission circuit 1 and the home-side transmission circuit 2 face each other via the optical fiber 30.
  • the information transmitted from the office-side transmission circuit 1 to the home-side transmission circuit 2 is transmitted to the office-side transmission logic circuit.
  • the signal is time-axis-compressed by the unit 11, converted into an optical pulse by the station-side electric / optical conversion circuit unit 12, and sent to the optical fiber 30 via the station-side optical coupler 13.
  • the optical pulse received from the optical fiber 30 via the in-home optical coupler 23 is converted back to an electrical signal in the in-home optical / electrical conversion circuit 24, which is further received in the in-home.
  • the logic circuit section 25 expands the time axis to extract the original speed information.
  • the time axis is compressed by the in-home transmission logic circuit 21 and the optical signal is transmitted by the in-home electric-optical conversion circuit 22. Then, the light is converted to an optical fiber 30 and transmitted to the optical fiber 30 via the optical coupler 23 inside the house.
  • the optical pulse received from the optical fiber 30 via the station-side optical coupler 13 is converted into an electric signal by the station-side optical / electrical conversion circuit section 14, and the station-side reception logic circuit section 15 Extend the time axis to extract the original speed information.
  • the station side control circuit section 16 generates a control signal and the like necessary for time axis operation from a clock pulse in the station.
  • the inside control circuit unit 26 extracts quick information necessary for time axis operation from the received pulse train, and generates necessary control signals and the like.
  • the downstream burst signal 1 1 1 2 transmitted from the station side transmission circuit 1 is received by the inside transmission circuit 2 after receiving the attenuation due to the loss in the optical fiber 30 and the propagation delay time (Tps).
  • the in-home transmission circuit 2 After receiving the downstream burst signal 1 1 1 2, the in-home transmission circuit 2 transmits the upstream burst signal 1 1 1 4 after a protection time (Tg) for preventing interference between upstream and downstream.
  • Tg protection time
  • the upstream burst signal 111 is received by the station side transmission circuit 1 after receiving the attenuation due to the loss in the optical fiber 30 and the propagation delay time (Tpr).
  • the occupation time (Tis) of the downstream burst signal 1 1 1 and the occupancy time (Tir) of the upstream burst signal are equal.
  • the downstream propagation delay time (Tps) and the upstream propagation delay time (Tpr) are equal.
  • Up 'occupation time of the downlink Pasuto signal (Tis, Tir) and uplink' becomes the downlink propagation delay time between (Tps, Tpr) and guard time (T g) the sum of Pasuto cycle time (Tb).
  • Echo canceller bidirectional optical transmission system (one-to-one connection: Fig. 9)
  • the office side echo canceller circuit section 7 and the office side subtracter 18 are provided, and the in-home transmission circuit 2 includes an in-home echo canceller circuit section 27 and an in-home subtractor 28.
  • the station-side transmission circuit 1 and the home-side transmission circuit 2 face each other via the optical fiber 30.
  • the information transmitted from the station side to the inside of the house is added with a frame synchronization signal and the like by the station side transmission logic circuit section 11, becomes an optical pulse by the station side electric / optical conversion circuit section 12, and becomes the station side optical coupler 1 It is sent to the optical fiber 30 via 3.
  • the received optical pulse is guided from the optical fiber 30 through the inside optical coupler 23 to the inside-home optical / electrical conversion circuit section 24, and the frame synchronization signal is processed by the inside reception logic circuit section 25. And then retrieve the original information.
  • a frame synchronization signal and the like are added by the inside-of-house transmission logic circuit 21 and are converted into optical pulses by the inside-of-house electrical-optical conversion circuit 22.
  • the light is sent to the optical fiber 30 via the optical coupler 23.
  • the received optical pulse is guided from the optical fiber 30 through the station-side optical coupler 13 to the station-side optical / electrical conversion circuit section 14, and the frame-side synchronization signal is sent to the station-side reception logic circuit section 15. After performing the above processing, extract the original information.
  • the above operation is the same as that of the time axis compression multiplexed bidirectional optical transmission system shown in Fig. 7, except that in the echo canceller bidirectional optical transmission system, during the information transfer, the data goes up on the optical fiber 30 and goes down in the Z direction.
  • the point that transmission signals are continuously and simultaneously mixed is different from the time axis multiplexed bidirectional optical transmission method.
  • the station-side echo canceller 17 performs a trace when starting communication.
  • the training signal 3 1 1 2 from the station side transmission logic circuit section 11 is transmitted as an optical signal 3 11 3 to the optical fiber 30 via the station side optical coupler 13.
  • the sum of the reflection signal 3 1 1 4 of the training signal 3 1 1 3 transmitted to the optical fiber 3 0 and the training signal 3 1 1 5 leaked by the optical coupler 13 at the station is the optical-to-electrical conversion at the station.
  • the signal is input to the circuit section 14 and converted into an electric signal.
  • the station-side echo canceller 17 based on the station-side training signal 3 1 1 2 Set its own operating parameters to generate a signal (called an echo signal) that cancels out the sum signal of the leakage signal 311 and the reflection signal 311 from the optical fiber. I do.
  • the station side subtractor 18 receives a signal from the station side optical / electrical conversion circuit section 14 from the inside of the house.
  • the leaked signal of the received signal and the station-side transmission signal is added, and an echo signal is added from the station-side echo canceller 17.
  • the output signal of the station side subtracter 18 becomes only the received signal from the inside of the house and is sent to the station side reception logic circuit 15. Since the operation of the echo canceller inside the house is the same, the description is omitted.
  • the station-side control circuit 16 generates necessary control signals such as a frame synchronization signal from the station-side terminal SCK.
  • the inside control circuit unit 26 extracts information such as a frame synchronization signal from the received pulse train, and generates a necessary control signal.
  • the echo canceller bidirectional optical transmission system also has a maximum applicable distance (Lmax) as a system due to restrictions due to optical fiber loss. This will be described later.
  • the upstream / downstream signals are separated in time, so that the optical coupler is simpler, but the transmission signal speed is lower than the information speed. More than twice as necessary.
  • the transmission signal speed is almost the same as the information speed, but a directional coupler must be used for the optical coupler to improve the separation between uplink and downlink. .
  • One-core same-wavelength time-axis compression multiplexed bidirectional optical transmission system (one-to-many connection -.mil)
  • the time-axis compression multiplexed bidirectional optical transmission system as a single-core bidirectional transmission system with the same wavelength is an economical single-core bidirectional optical transmission system in which multiple users share an optical fiber and information band using an optical branching device. It is applied to the same wavelength one-to-many connection type optical branching bidirectional optical transmission system.
  • This single-core, one-wavelength, one-to-many connection optical branching bidirectional optical transmission system uses PON (Passive PT / JP2002 / 007427
  • optical network This is a type of optical transmission system called an “optical network” system.
  • the PON system is detailed in, for example, the document “xDS L / FTTH” (ASCII Press Office), and thus description thereof is omitted here.
  • an optical transmission line termination circuit (hereinafter referred to as an OLT (Optical Line Termination circuit)) corresponding to the above-mentioned station-side transmission circuit 1 10.
  • an optical network unit (hereinafter referred to as ONU (Optical Network Unit)) 201 corresponding to the in-home transmission circuit 2 are connected in a 1: N connection via an optical branching device 300.
  • N is an integer indicating the number of connected ONU.
  • the transmission information is accommodated in a predetermined time slot, and control bytes necessary for communication as a PON system for performing one-to-many connection type optical branching bidirectional optical transmission are added and transmitted as necessary.
  • information time slots addressed to each ONU 201 are multiplexed and continuously transferred. Extract only information time slots addressed to you.
  • the upstream direction from each ONU 201 to the OLT 101 is transferred in units of a predetermined time slot specified by the OLT 101. That is, as shown in FIG. 12, in the burst period Tb, the time taken for the downlink burst signal 1 1 1 2 to return at the station side —LT 101 —home side ONU 201 —station side OLT 101 is the entire time.
  • the optical pulse 21 12 for delay time measurement is sent from the OLT 101 to the new ONU 201 1 inside the new home, and the delay time Ta unique to the ONU 201 1 inside the home is measured. deep. Then, a time slot Tsl is allocated to the existing ONU 2012 and a time slot Ts2 is allocated to the new ONU 2011 to transmit a burst signal.
  • the new ONU 201 1 when the new ONU 201 1 is installed while the existing ONU 201 2 is operating, the information that ⁇ unassigned time slots should be answered by ONUs '' in the ONU operation guarantee window Tw from the station side LT 101 is included.
  • the pulse train 21 12 for delay time measurement is transmitted by broadcast.
  • the new ONU 201 1 Upon receiving this, the new ONU 201 1 returns a response pulse train 2 114 including its own ID information.
  • the OLT 101 When the OLT 101 receives the response from the newly established ONU 201 1, the delay time T a And transmit the designated time slot and delay adjustment time T d to the new ONU 2011 in the frame information F.
  • the pulse train for delay time measurement 2112 can be inserted in every burst period, and a certain line can be inserted once every few seconds, and even when an ONU is newly established, it can be inserted by an external instruction. You can also.
  • the newly installed ONU 201 1 reads out its time slot position Ts2 and delay adjustment time Td from the frame information F at the head of the burst signal from the station side LT 101, and sends it from the station OLT 101 in the form of a broadcast. Only the information of the specified time slot Ts2 is received from the incoming information sequence.
  • the new ONU 201 1 sets the transmission timing to the OLT 101 on the station side as the protection time Tg (fixed value), the delay adjustment time Td (depending on the distance between the ONU and OLT), and the time slot position designation time Tt (for each ONU). Different) and sends the information to the specified time slot Ts2.
  • optical signals are transferred after being compressed on the time axis in the upstream and downstream directions.
  • the time axis compression operation and the decompression operation in the transmission of information transmitted from the station side to the house side and information in the opposite direction from the house side to the station side are performed as shown in FIG.
  • the bit stream of the transmission information of the station side LT 101 is compressed on the time axis at every noast period (Tb), put into, for example, the time slot Tsl in the signal 1112, and sent to the ONU 201 on the home side.
  • the bit stream compressed in the time axis of the time slot Tsl is expanded in the time axis by the in-house ONU 201 to return to the original speed, and is used as the bit stream of the in-house received information.
  • the difference between the single-core time axis compression multiplexed bidirectional optical transmission system and the one-to-many connection type optical branching bidirectional optical system based on the PON system is that the upstream information from each connected ONU 201 is transmitted to the optical branching device station.
  • TDMA Time Domain Multiple Access
  • the information time slots Tsl and Ts2 are transmitted at a predetermined timing based on the transmission delay time instruction from the OLT 101.
  • the information time slots Tsl and Ts2 from the ONU Be identified.
  • FIGS. 12 and 13 The operation of FIGS. 12 and 13 will be further described with reference to FIG.
  • the downstream burst signal 11 12 transmitted from the OLT 101 at the station is data containing information time slots addressed to each ONU 201, and receives the attenuation due to loss and propagation delay time (Tps) in the optical fiber. Received at k.
  • the data received by each ONU 201 has different attenuation and propagation delay time according to the distance from the OLT 101.
  • the on-premises ONU 201 extracts the information time slot addressed to the ONU # k from the downlink burst signal 11 12, and upon completion of reception, sets the uplink time from each ONU 201 during the protection time (Tg) to prevent uplink and downlink interference.
  • Tg protection time
  • Td delay adjustment time
  • the information is transferred to the time slot Ts # k specified by the OLT 101 in the time slot of the upstream burst signal 1114.
  • This upstream burst signal 1114 is received by the station side after receiving attenuation due to loss and propagation delay time (Tpr) in the optical fiber 30.
  • the upstream burst signal 1114 received by the station side ⁇ LT 101 is a set of information time slots transmitted from each ONU 201.
  • the occupation time (Tis) of the downlink burst signal 11 and 12 is equal to the occupation time (Tir) of the uplink burst signal.
  • the downstream propagation delay time (Tps) and the upstream propagation delay time (Tpr) are equal for each ONU 201, but different ONU 201s have different distances from OLT 101, so the values differ for each ONU 201. .
  • the sum of the occupation time of the uplink Z downlink burst signal, the uplink delay time, the guard time, and the delay adjustment time is the burst cycle time (Tb).
  • Lmax maximum applicable distance
  • This maximum distance is used to determine the delay time that each ONU 201 adjusts to be logically equidistant from the OLT 101. That is, in order to avoid collision of the upstream burst signal 1114 from each ONU 201 and thereby guarantee the operation of all ONUs, each ONU 201 sends out so that all ONUs 201 are at the logical distance of Lmax. Information time slot delay time adjust.
  • This delay time adjustment mechanism will be described with reference to FIG. In this figure, two home interior ⁇ NUs, a home interior O NU # j and an ONU # k, are connected.
  • the OLT 101 on the station measures the transmission path distance to each ONU 201 inside the house, and based on the measurement result, the OLT 101 on the station notifies each ONU 201 inside the house.
  • the delay adjustment time Tdi for the ONU # i inside the house is set so that the following relationship is established between the propagation delay time Tpi corresponding to the transmission distance Li and the maximum propagation time Tpmax corresponding to the maximum applicable distance Lmax. I can decide.
  • Tg is the protection time
  • ⁇ TDR Optical Time Domain Keflectometer
  • the operator manually instructs the optical fiber termination to connect the measuring instrument manually, and controls the optical switch according to the instruction from the operation support system. It was started by connecting to the system, and in each case, operator intervention was required.
  • the optical transmission device and the measuring device for detecting the optical fiber cutting point were completely different, and there was no integrated device.
  • the present invention relates to a method and system for performing bidirectional optical transmission at the same wavelength between an office-side transmission circuit and a home-side transmission circuit by using a single-core optical fiber, wherein a special measuring device is connected to detect an optical fiber disconnection fault.
  • the purpose is to be able to automatically detect without detecting. Disclosure of the invention
  • the fault point detection of the optical fiber is limited to the detection of the break point, and the operation of the station side transmission circuit is measured from the normal operation to the time from the transmission of the isolated pulse for measuring the fiber cut point to the reception. This is realized by switching to a cutting point detection operation.
  • the station-side transmission circuit detects the corresponding home-side transmission circuit based on the response fault of the home-side transmission circuit, and the station-side transmission circuit detects the response fault. And a second step of detecting a fault point by transmitting an optically isolated pulse toward the in-home transmission circuit corresponding to.
  • the station-side transmission circuit generates a response failure alarm, and at the instruction of the operator, carries a measuring device called an OTDR in front of the optical fiber termination, causing a failure. The measurement was performed by replacing the optical connector with an optical fiber that was thought to have been accessed.
  • the station-side transmission circuit detects this (first step), and automatically switches from the normal operation to the failure point detection operation.
  • the distance to the failure point can be measured (second step).
  • the disconnection point can be detected in the transmission circuit without using the OTDR. For this reason, it is not necessary to replace the optical connector and connect the measuring instrument, which reduces the number of measurement operations, and also allows the measuring instrument to be accidentally connected to a normal optical fiber due to human error. Can be prevented. Also, large-scale equipment for connecting the measuring instrument via the optical splitter and the optical switch is not required.
  • the station-side transmission circuit and the home-side transmission circuit have a one-to-one connection relationship as shown in FIGS. 7 and 9, the station-side transmission circuit performs the home step in the first step.
  • the optical isolated pulse is sent to the home transmission circuit in the second step to detect a fault point.
  • the station-side transmission circuit and the home-side transmission circuit have a one-to-many connection relationship as shown in FIG.
  • the circuit when detecting the response failure for any one of the home inside transmission circuits in the first step, in the second step, the optical isolated pulse is detected within a predetermined operation guarantee time.
  • the signal is sent to the transmission path to detect a fault point. That is, the station-side transmission circuit operates within the time to guarantee the operation of the ONU inside the entire house until the burst signal 1 1 1 2 shown in FIGS. 12 and 13 is transmitted from the station-side OLT and returned.
  • An optical isolated pulse is sent to ONU inside each house to detect the harmful points in Chapter P.
  • a measuring instrument called an OTDR is carried in front of the optical fiber termination by an operator's instruction, and the optical fiber that seems to have failed is replaced by an optical connector and accessed for measurement. I was doing.
  • the measuring instrument was connected via an optical splitter and an optical switch, the operation support system operated the optical switch and performed measurement to detect a cutting point.
  • the breakpoint of the trunk fiber from the station-side transmission circuit to the optical branching device can be detected using OTDR, but a branch line connected from the optical branching device to each user's home. Since the test light pulse is split and multiple-reflected to detect the break point in the fiber, it was difficult to specify which branch fiber failed.
  • the operation of the optical line termination circuit on the optical line at the station side is automatically switched from the normal operation to the operation of detecting the disconnection point.
  • the distance to the cutting point can be measured.
  • the optical fiber cutting point can be detected without affecting the operation.
  • the operation support system receives the notification and instructs the station-side transmission circuit to switch the station-side transmission circuit from the normal operation to the disconnection point detection operation. Distance can also be measured.
  • the present invention has means for autonomously notifying the operation support system of an optical fiber cut point detection result from the optical transmission device that has detected a failure, so that there is no need for operator intervention when a failure occurs.
  • the station-side transmission circuit detects a corresponding in-home transmission circuit based on a response failure of the in-home transmission circuit, and transmits the in-home transmission corresponding to the response failure.
  • a fault point is detected by transmitting an optical isolated pulse toward a circuit.
  • the station-side transmission circuit when the station-side transmission circuit and the home-side transmission circuit have a one-to-many connection relationship, the station-side transmission circuit includes the home-side transmission circuit.
  • the optical isolated pulse can be transmitted to the transmission line within a predetermined operation failure time to detect a failure point.
  • the station side transmission circuit when detecting the response failure, notifies the operation support system of the result, and receives a switching instruction from the normal operation to the disconnection point detection operation from the operation support system. In this case, the fault check can be performed.
  • the in-home transmission circuit corresponding to the response failure of the in-home transmission circuit is provided.
  • a transmission circuit comprising: first means for detecting; and second means for detecting a point of failure by transmitting an optical isolated pulse to a home-side transmission circuit corresponding to the response failure. Is done.
  • the second means transmits the optical isolated pulse to the transmission path within a predetermined operation guarantee time to perform a failure point detection. Can be.
  • the first means when detecting the response failure, The second means can detect a failure point when the operation support system notifies the operation support system of the result and when the operation support system receives an instruction to switch from the normal operation to the disconnection point detection operation.
  • the bidirectional optical transmission can be performed by time-axis compression multiplexing or an echo canceller method.
  • FIG. 1 is a block diagram showing an embodiment of a station-side transmission circuit according to the present invention.
  • FIG. 2 is a block diagram showing a connection relationship between the station-side transmission device and the operation support system.
  • FIG. 3 is a diagram showing an embodiment of an optical fiber cutting point detection result notification message sent from the station side transmission device to the operation support system according to the present invention.
  • FIG. 4 is a diagram for explaining an optical isolated pulse between a station side and a cutting point when an optical fiber is cut in the optical transmission system (one-to-one connection type) according to the present invention.
  • FIG. 5 is a block diagram showing another embodiment (echo canceller system) of the station side transmission circuit according to the present invention.
  • FIG. 6 is an explanatory diagram of an operation of an optical isolated pulse transmitted when an optical fiber is cut by the optical transmission system (one-to-many connection type) according to the present invention.
  • FIG. 7 is a block diagram of a conventionally known one-core one-wavelength time-axis compression one-to-one connection type bidirectional optical transmission system.
  • FIG. 8 is an explanatory diagram of an operation during one burst period in a normal operation in the one-core same-wavelength time-axis compression multiplexed bidirectional optical transmission system shown in FIG.
  • FIG. 9 is a block diagram of a conventionally known echo canceller bidirectional optical transmission system.
  • FIG. 10 is an explanatory diagram of a training operation in the station-side transmission circuit of the echo canceller bidirectional optical transmission system shown in FIG.
  • FIG. 11 is a block diagram of a conventionally known one-core one-wavelength, time-axis-compressed, one-to-many-connection optical branching bidirectional optical transmission system.
  • FIG. 9 is an explanatory diagram of the operation when measuring the delay time of a newly installed ONU in the directional transmission system.
  • FIG. 13 is a diagram for explaining a time axis compression operation in a conventionally known one-core one-wavelength time-axis compression one-to-many-connection type optical branching bidirectional transmission system.
  • FIG. 14 is a diagram illustrating the operation during one burst period during normal operation in a conventionally known one-core one-wavelength, time-axis-compressed, one-to-many-connection type optical branching bidirectional optical transmission system.
  • Fig. 15 is a diagram for explaining the delay time adjustment operation at each ONU during normal operation in a conventionally known one-core one-wavelength, time-axis-compressed, one-to-many-connection optical branching bidirectional optical transmission system.
  • FIG. 14 is a diagram illustrating the operation during one burst period during normal operation in a conventionally known one-core one-wavelength, time-axis-compressed, one-to-many-connection type optical branching bidirectional optical transmission system.
  • Fig. 15 is a diagram for explaining the delay time adjustment operation at each ONU during normal operation in a conventionally known one-core one-wavelength, time-axis-compressed, one-to-many-connection optical branching bidirectional optical transmission system.
  • FIG. 1 shows an embodiment of a station-side transmission circuit according to the single-core same-wavelength time-axis compression multiplex bidirectional optical transmission system according to the present invention.
  • the station-side transmission logic circuit section 11 is composed of a station-side transmission logic circuit 111, an isolated pulse generation circuit 112, and a transmission-side operation switching switch 113.
  • the circuit section 16 is composed of a station side control circuit 161 and a timer circuit 162, and the station side reception logic circuit section 15 is an equalization amplifier circuit 151, a timing extraction circuit 152, an identification circuit 153, a station side reception logic circuit 154, and a gain. It is characterized by comprising a switching switch 155, an identification clock switching switch 156, and a receiving-side operation switching switch 157.
  • the station-side electric / optical conversion circuit section 12 includes a driver circuit 121 and a light emitting element 122.
  • the optical-to-electrical conversion circuit section 14 on the station side comprises a light receiving element 14 1 and a preamplifier circuit 14 2.
  • the switches 113 and 115 to 157 are located on the opposite side of the figure. That is, the station-side transmission logic circuit 111 is connected to the station-side electrical-optical conversion circuit section 12, the switch 155 is connected to the variable gain terminal G2, and the timing extraction circuit 155 is an identification circuit 155. 3 and the identification circuit 15 3 is connected to the station-side reception logic circuit 15 4.
  • FIG. 2 shows a connection relationship between the station-side transmission device 10 and the operation support system 7.
  • one station-side transmission device 10 has a plurality of station-side transmission circuits 1 shown in FIG.
  • N station-side transmission circuits 1 # 1 to 1 # N are connected to other devices via a multiplexing / demultiplexing unit 4.
  • each station side transmission circuit 1 # 1 to 1 #N and the setting control for each station side transmission circuit 1 are collected by the common control unit 5 of the station side transmission device 10, and are configured with LAN, etc. It communicates with the operation support system (OSS) 7 via the information transfer network 6. Normally, communication between the operation support system and the transmission device is performed in the form of a packet message shown in Fig. 3.
  • OSS operation support system
  • the operation support system 7 has an input / output device 8 which controls a human machine interface with an operator.
  • a personal computer or a workstation is usually used for the input / output device 8.
  • the optical fiber 30 # 1 to 30 # N from each station side transmission circuit 1 is connected to an optical fiber extending to the user's home by an optical fiber termination frame 9 via an optical connector 90, where the inside of the station is connected. And failure outside the station.
  • the light emission pulse of the optically isolated pulse sent from the station side transmission circuit should be twice or more than the light emission pulse in normal operation. No. Needless to say, in order to accurately determine the distance to the cutting point, it is only necessary to perform multiple measurements and average the values.
  • an alarm is issued from the station-side control circuit 161 via the common control unit 5 of the station-side transmission device 10.
  • Tell system 7 The operator of the operation support system 7 refers to the alarm and issues an instruction to the corresponding station side transmission circuit 1 to switch from the normal operation to the disconnection point detection operation.
  • the transmission side operation switch 1 13 when an instruction from the operation support system 7 is received, the transmission side operation switch 1 13, the gain switch 1 55, the identification clock switch 1 56, and the reception side operation switch Switch 157 to the cutting point detection operation mode shown in Fig. 1.
  • the station side transmission logic circuit section 11 When the operation of the station side transmission circuit 1 is switched to the break point detection operation, the station side transmission logic circuit section 11 propagates an optical signal equivalent to twice the maximum applicable distance (Lmax) as shown in Fig. 4. An isolated pulse is generated with a period longer than the time (Tmax), and the isolated pulse becomes an optical isolated pulse 3 1 2 in the optical-to-optical conversion circuit section 12 on the station side. Sent to 30.
  • the optically isolated path 312 propagates through the optical fiber 30 from the station side to the home side while being attenuated due to optical loss, and is almost totally reflected at the cutoff point 31 of the optical fiber. Then come back to the station.
  • the reflected light isolated pulse 3 14 received via the optical coupler 13 on the station side is converted into an electric signal by the optical-to-electrical conversion circuit section 14 on the station side and input to the receiving logic circuit section 15 on the station side. .
  • the station side reception logic circuit section 15 is different from the normal operation state, and the equalization function of the regenerative relay function (equalization amplification, timing extraction and identification function) is fixed to the maximum gain.
  • the identification function waits for the reflected light isolated pulse 314 at the normal threshold (normally 0.5).
  • the station-side control circuit 16 starts a timer for counting the time from the point at which the above-mentioned isolated panel was generated by the station-side transmission logic circuit 11, and the received reflected light isolated pulse 3 1 4 has an identification function.
  • the timer circuit 16 2 is stopped at the time when it is determined that there is a timer. Dividing the value of this timer by 2 and dividing by the propagation delay time per unit distance of the light in the optical fiber gives the distance (L) from the optical line end to the cutting point of the optical fiber.
  • the clock for the timer may be used exclusively for the timer, or may be used by dividing or multiplying the clock CP of the transmission line signal as it is.
  • FIG. 5 shows an embodiment of a station side transmission circuit using the echo canceller bidirectional optical transmission system according to the present invention.
  • the station side transmission logic circuit section 11 is composed of the station side transmission logic circuit section 111, the isolated pulse generation circuit 112, and the transmission side operation switching switch 113.
  • the station side control circuit section 16 is composed of a station side control circuit 16 1 and a timer circuit 16 2
  • the station side reception logic circuit section 15 is an equalizing amplifier circuit 15 1 and a timing extraction circuit 1 5 2, an identification circuit 15 3, a station-side reception logic circuit 15 4, a gain switching switch 15 5, an identification clock switching switch 15 6, and a reception-side operation switching switch 15 7, and It is characterized in that a station side echo canceller operation switching switch 17 1 is added to the station side echo canceller circuit section 17.
  • the station-side electrical / optical conversion circuit 12 is composed of a driver circuit 12 1 and a light emitting element 122, and the station-side optical / electrical conversion circuit 14 is comprised of a light receiving element 14 1 and a preamplifier circuit.
  • the point composed of 1 and 2 is the same as the conventional one.
  • the transmitting side operation switching switch 13 when an instruction is received from the operation support system 7, the transmitting side operation switching switch 13, the gain switching switch 15 5, the identification switch 15 6, the receiving side operation Selector switch 157 and station side echo canceler operation changeover switch 171 Switch to cut-point detection operation mode.
  • Isolated pulse generation circuit 1 1 2 In the isolated pulse repetition period pulse and transmission line clock Generates an isolated pulse for cutting point detection from the pulse CP and sends it to the driver circuit 12 1 and the station-side echo canceller circuit 17 via the transmission-side operation switching switch 1 13 and the timer circuit 16 2 Also sends an isolated pulse to the start terminal of.
  • the station-side echo canceller circuit unit 17 stops the operation including the training because the station-side echo canceller operation switching switch 17 1 is OFF.
  • the driver circuit 122 drives the light emitting element 122 with an isolated pulse and converts it into an optical isolated pulse. This optical isolated pulse is sent to the optical fiber 30 through the optical coupler 13 on the local side.
  • the propagation time is twice the propagation time of the maximum transmission distance (Lmax) ( An isolated pulse may be transmitted at a period longer than Tmax).
  • the transmitted light isolated pulse 3 12 is totally reflected at the cut point 3 1 of the optical fiber 30 and becomes the received light isolated pulse 3 14.
  • the light isolated pulse 3 14 reflected at the cut point 31 of the optical fiber enters the light receiving element 14 1 through the local optical coupler 13 and is extracted as an electric signal by the preamplifier circuit 14 2. You. This electric signal is applied to the station side subtractor 18, but since the station side echo canceler circuit section 17 has stopped operating, it is directly amplified by the equalizing amplifier circuit 15 1 and the identification circuit 15 3 I can get calories.
  • the equalizing amplifier circuit 15 1 has a fixed gain, but since the AGC (Automatic Gain Control) is normally operating, the equalizing amplifier circuit 15 1 The gain is fixed to the maximum gain with the gain switch 1 5 5.
  • AGC Automatic Gain Control
  • the clock of the identification circuit 1553 uses the clock extracted by the timing extraction circuit 152 from the received signal.
  • the identification clock switching switch 1556 is switched and the transmission side is switched. Is used.
  • the time width of the transmitted light isolated pulse 3 1 2 is set to the reciprocal of the transmission line cut-off frequency by 2 Needless to say, it should be doubled or doubled.
  • Timer times Path 162 starts measurement when a pulse is applied to the start terminal, and stops measurement when a pulse is applied to the stop terminal.
  • the pulse applied to the start terminal of the timer circuit 16 2 must be delayed or discriminated. It goes without saying that the switching of the receiving-side operation switching switch 157 for sending the output to the stop terminal of the timer circuit 162 may be delayed.
  • the value of the measured time value 1 Z 2 is sent to the station-side control circuit 16 1, and further via the common control unit 5 of the station-side transmission device 10. Sent to the operation support system 7. The operator looks at the result of the optical fiber break point detection and arranges for repair of the optical fiber.
  • the conversion processing into the distance may be executed in the common control unit 5 or the operation support system 7 of the station-side control circuit 16 1 or the station-side transmission device 10.
  • the time window T w for guaranteeing the operation of the ONU 210 furthest inside the house is considered. Is provided.
  • the total ONU operation guarantee window Tw requires a time longer than the propagation delay time of twice the longest distance (Lmax) plus the protection time (Tg).
  • the isolated pulse generation circuit 112 generates an isolated pulse for cutting point detection from the burst frame pulse F shown in Fig. 12 and the transmission line clock pulse of the bit stream shown in Fig. 13 and switches the transmission side operation.
  • the signal is sent to the driver circuit 121 via the switch 113 and an isolated pulse is sent to the start terminal 162a of the timer circuit 162.
  • the driver circuit 122 drives the light emitting element 122 with an isolated pulse and converts it into an optical isolated pulse.
  • the optical isolated pulse is sent to the optical fiber 30 through the optical coupler 13 on the optical line side.
  • the transmitted light isolated pulse 3 1 2 is totally reflected at the cutting point 3 0 3 (when the supporting fiber 3 0 2 is present), for example, in the case of the optical fiber 30, and is coupled to the station side. It returns to the station side receiving logic circuit section 15 through the device 13 as the received light isolated pulse 3 14.
  • the station side receiving logic circuit section 15 is different from the normal operation state, in which the equalization function of the regenerative relay function (equalization amplification, timing extraction and identification function) is fixed to the maximum gain, and the identification function is It waits for a reflected light isolated pulse at a normal threshold (usually 0.5). That is, the light isolated pulse is extracted as an electric signal by the preamplifier circuit 142 to the light receiving element 144.
  • This electric signal is amplified by the equalizing amplification circuit 15 1, and is amplified by the identification circuit 15 3.
  • the equalizing amplifier circuit 15 1 has a fixed gain, but since the AGC (Automatic Gain Control) is normally operating, the equalizing amplifier circuit 15 1 The gain is fixed to the maximum gain with the gain switching switch 1 5 5.
  • the clock of the identification circuit 1553 uses the clock extracted from the received signal by the timing extraction circuit 152, but in the break point detection operation mode, the identification clock switching switch 1556 is switched to change the transmission side.
  • the time width (connection time) of the transmitted solitary pulse is twice or twice the reciprocal of the transmission line clock frequency. That is all.
  • Timer circuit 162 starts measurement when a pulse is applied to start terminal 162a, and stops measurement when a pulse is applied to stop terminal 162b.
  • delay the pulse applied to the start terminal 16 2 a of the timer circuit 16 2 It is sufficient to delay the switching timing of the receiving-side operation switching switch 157 for sending the input or the identification output of the identification circuit 153 to the stop terminal 162 b of the timer circuit 162.
  • the value of the measured time value 1 Z 2 is sent to the station side control circuit 16 1, and furthermore, the common control unit of the station side transmission device 10. It is sent to the operation support system 7 via 5.
  • this timer when the value of this timer is divided by 2 and further divided by the propagation delay time per unit distance of the light in the optical fiber, the distance (L) from the station-side transmission circuit to the cutting point 303 of the optical fiber 30 is calculated. Can be requested.
  • the clock for the timer may be used exclusively for the timer, or the clock of the transmission path signal may be used as it is, or may be divided or multiplied. The operator looks at the result of detecting the optical fiber cutting point and arranges for repair of the optical fiber 30.
  • the timer measurement value itself may be used as the value.
  • the conversion of the optical fiber 30 into the distance to the cut point 303 is performed by the station-side control circuit 161, the common control unit 5 of the station-side transmission device 10, or the operation support system 7. Needless to say, this may be done.
  • control for switching the operation of the station side transmission circuit 1 from the normal operation to the disconnection point detection operation is performed manually or from the operation support system 7 from the outside. It may be performed automatically.
  • the station-side control circuit 161 of the station-side transmission circuit 1 automatically switches off from the normal operation in the same manner as above. Switch to break point detection operation.
  • the common control unit 5 of the station-side transmission device 10 uses the station-side transmission circuit number (1 # 1 to 1 # N) that detected the failure and the numerical value of the measurement result as an operation support system in the form of a bucket message. Notify 7 autonomously.
  • Fig. 3 An example of this packet message is shown in Fig. 3, where "message number” indicates an identifier for identifying the message between the station-side transmission device and the operation support system, and "transmission circuit number” usually indicates “ Indicates the physical location identifier consisting of “building name, floor, rack number, unit number, shelf number, package number, interface number”.
  • the “type” is a major alarm such as LOS (Loss Of Signal) or LOF (Loss Of Frame), performance information such as bit error, or a numerical value such as the result of optical fiber disconnection point detection.
  • LOS Liss Of Signal
  • LOF Liss Of Frame
  • performance information such as bit error
  • a numerical value such as the result of optical fiber disconnection point detection.
  • Numerical data indicates specific numerical values such as the number of bit errors and the numerical value of a detection result of an optical fiber cut point.
  • the operation support system 7 can identify the user's home from the user data in the database and the transmission circuit number, match the distance data to the failure point with the route diagram of the optical fiber cable, and identify the failure point.
  • the operation mode is the normal operation mode, and the mode is switched to the disconnection inspection operation mode only during the entire ONU operation guarantee window Tw.
  • optical isolated pulse used for detecting the fault point is within the operation guarantee window Tw, other ONUs that have not caused the branch fiber breakage are not affected by this break point detection operation, and the normal service is not affected. Operation is not hindered.
  • the common control unit 5 of the station-side transmission device 10 autonomously notifies the operation support system of the station-side transmission circuit number that detected the failure and the numerical value of the measurement result to the operation support system in the form of a bucket message.
  • the example is the same as that shown in Fig. 3, except that the ONU number is added to the end of the transmission circuit number.
  • the measurement function is realized by switching the operation of the station-side transmission circuit of the single-core same-wavelength bidirectional optical transmission system, there is the advantage that the cost increase by adding the function is small. Also, since there is almost no increase in circuit scale, there is an advantage that functions can be integrated into a conventional optical transceiver module.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Optical Communication System (AREA)

Abstract

La présente invention concerne un procédé et un système de transmission optique bidirectionnelle avec la même longueur d'onde entre un circuit de transmission de bureau et un circuit de transmission de terminal utilisateur, par l'intermédiaire d'une fibre optique à un coeur. Lorsque survient un problème de déconnexion de fibre optique, le circuit de transmission de bureau localise le circuit de transmission de terminal utilisateur en détectant le problème de réponse du circuit de transmission de terminal utilisateur, de façon à détecter automatiquement le problème de déconnexion de fibre optique, sans relier n'importe quel instrument de mesure spécifique, et envoie une impulsion optique isolée au circuit de transmission de terminal utilisateur correspondant au problème de réponse, le point d'apparition du problème étant localisé.
PCT/JP2002/007427 2002-07-23 2002-07-23 Procede et systeme de transmission optique Ceased WO2004010612A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
PCT/JP2002/007427 WO2004010612A1 (fr) 2002-07-23 2002-07-23 Procede et systeme de transmission optique
JP2004522705A JP4044558B2 (ja) 2002-07-23 2002-07-23 光伝送装置及びシステム
US11/039,916 US20050123293A1 (en) 2002-07-23 2005-01-24 Optical transmission method and system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2002/007427 WO2004010612A1 (fr) 2002-07-23 2002-07-23 Procede et systeme de transmission optique

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WO2004010612A1 true WO2004010612A1 (fr) 2004-01-29

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WO (1) WO2004010612A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006180475A (ja) * 2004-12-21 2006-07-06 Alcatel 受動光ネットワーク監視方法および受動光ネットワーク
JP2006197489A (ja) * 2005-01-17 2006-07-27 Nippon Telegr & Teleph Corp <Ntt> 光波長多重システム、光終端装置および光ネットワークユニット
WO2008092397A1 (fr) * 2007-01-26 2008-08-07 Huawei Technologies Co., Ltd. Procédé de repérage de point d'événement de fibre, et réseau optique et équipement de réseau associés
JP2009232077A (ja) * 2008-03-21 2009-10-08 Nec Corp 局側終端装置、通信システム、加入者装置管理方法、および局側終端装置のプログラム
JP2015133645A (ja) * 2014-01-15 2015-07-23 日本電信電話株式会社 ノード及びスケジューラ
JP2017521981A (ja) * 2014-06-27 2017-08-03 ソリッド システムズ インコーポレイテッド 光通信線路監視装置及び方法

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JPS5219005A (en) * 1975-08-06 1977-01-14 Central Res Inst Of Electric Power Ind Optical fiber communication system
JPH02264527A (ja) * 1989-04-04 1990-10-29 Nec Corp 単条光ファイバ双方向通信方式
JPH07212280A (ja) * 1994-01-14 1995-08-11 Fujitsu Ltd 通信装置の自己診断方式
JPH09205452A (ja) * 1996-01-25 1997-08-05 Fujitsu Ltd 光加入者線伝送方法
JPH11340916A (ja) * 1998-05-26 1999-12-10 Nec Corp 光通信システムおよびその局装置
JP2000059654A (ja) * 1998-08-07 2000-02-25 Hitachi Denshi Ltd 双方向ディジタル信号伝送装置
JP2000312169A (ja) * 1999-04-28 2000-11-07 Nec Corp 通信システム及び方法、並びに通信局装置

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5219005A (en) * 1975-08-06 1977-01-14 Central Res Inst Of Electric Power Ind Optical fiber communication system
JPH02264527A (ja) * 1989-04-04 1990-10-29 Nec Corp 単条光ファイバ双方向通信方式
JPH07212280A (ja) * 1994-01-14 1995-08-11 Fujitsu Ltd 通信装置の自己診断方式
JPH09205452A (ja) * 1996-01-25 1997-08-05 Fujitsu Ltd 光加入者線伝送方法
JPH11340916A (ja) * 1998-05-26 1999-12-10 Nec Corp 光通信システムおよびその局装置
JP2000059654A (ja) * 1998-08-07 2000-02-25 Hitachi Denshi Ltd 双方向ディジタル信号伝送装置
JP2000312169A (ja) * 1999-04-28 2000-11-07 Nec Corp 通信システム及び方法、並びに通信局装置

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006180475A (ja) * 2004-12-21 2006-07-06 Alcatel 受動光ネットワーク監視方法および受動光ネットワーク
JP2006197489A (ja) * 2005-01-17 2006-07-27 Nippon Telegr & Teleph Corp <Ntt> 光波長多重システム、光終端装置および光ネットワークユニット
WO2008092397A1 (fr) * 2007-01-26 2008-08-07 Huawei Technologies Co., Ltd. Procédé de repérage de point d'événement de fibre, et réseau optique et équipement de réseau associés
US8290364B2 (en) 2007-01-26 2012-10-16 Huawei Technologies Co., Ltd Method, optical network and network device for locating fiber events
JP2009232077A (ja) * 2008-03-21 2009-10-08 Nec Corp 局側終端装置、通信システム、加入者装置管理方法、および局側終端装置のプログラム
JP2015133645A (ja) * 2014-01-15 2015-07-23 日本電信電話株式会社 ノード及びスケジューラ
JP2017521981A (ja) * 2014-06-27 2017-08-03 ソリッド システムズ インコーポレイテッド 光通信線路監視装置及び方法

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