JP4129028B2 - Optical transmission system and optical repeater - Google Patents

Description

  The present invention relates to an optical transmission system and an optical repeater, and more particularly to a PON type optical transmission system and an optical repeater thereof.

In an optical network such as FTTH and CATV, a PON (Passive Optical Network) in which an optical transmission line connected to a center is branched by a passive splitter and installed to a plurality of subscribers' homes.
Type optical transmission systems are used. Such an optical transmission system is also called a PDS (Passive Double Star).

In such an optical transmission system, a splitter is connected to an optical fiber drawn out from an OSU (Optical Subscriber Unit) in an optical line terminator (OLT) of a center to a user side, and is branched into a plurality by the splitter. The optical transmission line is connected to an optical network unit (ONU) of a plurality of users via an optical fiber.

  In a PON type optical transmission system in which an OLT and a plurality of ONUs are connected by an optical fiber and a splitter, a configuration in which an optical repeater is connected to the optical transmission line between the OLT and the splitter in order to extend the optical transmission line over a long distance It has been known.

  Further, a system that can perform wavelength division multiplex communication (WDM) by connecting MUX / DEMUX and an optical repeater to an existing optical transmission system is described in Patent Document 1 below. The optical repeater has a configuration as shown in FIG.

The wavelength conversion device 101 includes first and second 3 dB couplers 102 and 103 provided at input / output ends of the OLT side and the ONU side, and includes the first 3 dB coupler 102 and the second 3 dB coupler 103. A light receiving element 104, a receiving circuit 105, a driving circuit 106, a light emitting element 107, and an isolator 108 are sequentially connected to the downstream signal system in the signal propagation direction, and the light receiving element 109, A receiving circuit 110, a driving circuit 111, a light emitting element 112, and an isolator 113 are connected in order.

In such a device, the optical signals output from the first and second 3 dB couplers 102 and 103 to the light receiving elements 104 and 09 are converted into electric signals by the light receiving elements 104 and 109 , and the electric signals are received. 3R or 2R processing is performed by the circuits 105 and 110, and further, the electrical signal subjected to the 3R or 2R processing is converted into an optical signal by the driving circuits 106 and 111 and the light emitting elements 107 and 112 and output to the isolators 108 and 113. Processing is performed. Note that 3R is a function of equalization amplification (reshaping), identification reproduction (regeneration), and retiming, and 2R is a function of identification reproduction and retiming.
JP 2002-261697 A

The CATV optical repeater is generally placed outdoors away from the OLT, and the output of the light emitting element in the CATV changes due to the difference in environmental temperature, or the relay becomes impossible due to a power failure, or the optical repeater It is necessary to manage the optical repeater in order to deal with events such as abnormal voltage fluctuations in the power supply unit, abnormal door opening in the housing, abnormal internal temperature rise, inundation, etc.

  For such management, there is a method in which a management electrical circuit is installed in the optical repeater and the management electrical circuit is connected to a telecommunication line. However, in order to install a new telecommunications line for managing the optical repeater, a large-scale construction is required, resulting in an increase in cost. In addition, when there is no room for laying a new telecommunications line, management of the optical repeater must be abandoned.

  On the other hand, optical multiplexing using optical signals with a wavelength dedicated to optical repeater management can be considered in addition to light with wavelengths normally used in optical transmission systems. A wavelength multiplexing device is required, and cannot be easily adopted from the viewpoints of cost and space.

  An object of the present invention is to provide an optical repeater and an optical transmission system in which a management function can be easily introduced from the viewpoints of cost and work.

A first aspect of the present invention for solving the above problems is a PON type in which a center side optical line terminator and one or more subscriber side optical line terminators are connected via a passive optical transmission line. An optical repeater used in an optical transmission system, comprising: a first electrical / optical conversion means connected to the optical transmission line on the center side optical line termination device side for performing photoelectric conversion and reverse photoelectric conversion; A second electrical / optical converting means connected to the optical transmission line on the side of the optical line terminator on the user side to perform photoelectric conversion and reverse photoelectric conversion; the first electrical / optical conversion means; and the second electrical conversion means. An electrical signal connection unit provided in the middle of the electrical transmission path connecting the optical conversion means, an ONU function unit connected to the electrical signal connection unit and performing processing according to the protocol of the PON interface,
A management function unit that is connected to the ONU function unit and performs monitoring control, and the management function unit includes the first electrical / optical conversion unit and the second electrical / optical conversion unit. A device signal and a sensor measurement value indicating the state of the device are inputted and monitored via a GPIO interface and an I2C interface provided in the ONU function unit periodically or at a predetermined timing, and the ONU function unit The device signal input from the management function unit and the relay device management signal including the sensor measurement value are multiplexed into a predetermined channel of the upstream signal input from the side optical line termination device via the electrical signal connection unit, and the The optical repeater transmits to the center-side optical line terminator via an electrical signal connection unit.

According to a second aspect of the present invention, in the optical repeater according to the first aspect, the predetermined channel is a maintenance channel defined by a PON protocol .

According to a third aspect of the present invention, there is provided a center-side optical line in which the optical repeater according to the first or second aspect and the optical repeater are connected by a passive first optical transmission line. An optical transmission system comprising: a termination device; and one or more subscriber-side optical line termination devices connected between the optical repeater device by a passive second optical transmission line.

According to a fourth aspect of the present invention, in the optical transmission system according to the third aspect , a plurality of the optical repeaters are connected via the first optical transmission line or the second optical transmission line. It is characterized by that.
more than

  According to the present invention, the first electric / optical converting means connected to the center side line terminating device and the second electric / optical converting means connected to the subscriber side line terminating device are provided. Since the transmission means for transmitting the management signal for the optical repeater is provided between the second electrical / optical conversion means, the optical repeater can be managed without installing a new management line. become.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a configuration diagram of a PON type optical transmission system according to an embodiment of the present invention.

  In FIG. 1, an optical transmission line having optical fibers 2 and 3 connected to a center-side optical line terminator (OLT) 1 such as CATV is connected to an optical coupler 5 via an optical repeater 4. The optical transmission path branched into a plurality by the optical coupler (optical multiplexer / demultiplexer) 5 is a plurality of subscriber line optical line terminators (ONUs) 7-through optical fibers 6-1,. 1,... 7-n (n is a natural number). Each of the ONUs 7-1,..., 7-n includes an optical transceiver 8a and an ONU function 8b connected thereto.

  Here, the term ONU generally includes the function of an optical transceiver. However, for the purpose of explaining the present invention, the ONU is divided into two parts, an optical transceiver and an ONU function. .

  OLT1, ONU7-1,... 7-n are, for example, GEPON (Gigabit Ethernet (registered trademark) PON) conforming to the EFM standard IEEE802.3ah, ITU-T recommendation G. 984. A device that conforms to regulations such as GPON (Gigabit Passive Optical Network) according to x is selected.

  The optical repeater 4 includes a first EO / OE unit (optical / electrical conversion means) 21 connected to the optical fiber 2 on the OTL 1 side, and a second EO / OE connected to the optical fiber 3 on the optical coupler 5 side. An OE unit (optical / electrical conversion means) 22, an electric line 23 for transmitting an electric signal between the first EO / OE unit 21 and the second EO / OE unit 22, and the electric line 23 are connected. Electrical signal connection unit 24, various devices 25 such as door opening / closing sensors, temperature sensors, power supply voltage sensors, alarms, heaters, and the like mounted in the optical repeater 4, and first and second EO / OE units 21 and 22 And a management function unit 26 that inputs / outputs detection signals, control / setting signals, and the like to / from various devices 25, and an ONU function unit 27 that inputs / outputs electrical signals between the electrical signal connection unit 24 and the management function unit 26. Have.

  The first EO / OE unit 21 electrically converts an optical signal propagating in the downstream direction from the center OTL 1 through the optical fiber 2 and then performs predetermined 3R or 2R processing and outputs the processed signal to the electric line 23. The electric signal propagated in the upstream direction from the second EO / OE unit 22 via the electric line 23 is converted into an optical signal and output to the optical fiber 2.

  The second EO / OE unit 22 converts an electrical signal propagated in the downstream direction via the electrical line 23 into an optical signal and outputs the optical signal to the optical fiber 3 on the subscriber's home side, while passing through the optical fiber 3. The optical signal propagating in the upstream direction is electrically converted, further subjected to 3R or 2R predetermined processing, and output to the electrical line 23.

  The electrical signal connection unit 24 branches a multi-channel electrical signal that is TDM (Time Division Multiplexed) according to the PON protocol specification that propagates in the downstream direction through the electrical line 23 to split the first EO / OE unit 21 and the ONU function unit 27. The TDM channel signal transmitted from the ONU function unit 27 in accordance with a predetermined PON protocol specification is multiplexed with the upstream electrical signal of the electrical line 23 and propagated to the electrical line 23. Yes.

  The management function unit 26 inputs the state monitoring signals of the first and second EO / OE units 21 and 22 and the signals of the devices in the various devices 25, and the first and second EO / OE units 21, 22 and a circuit configuration for outputting signals for controlling the devices in the various devices 25 and setting conditions.

  The management function unit 26 includes a CPU, a storage element, and the like, and can be connected to the OTL 1 by using the maintenance channel on the PON protocol by the ONU function unit 27. Alternatively, the LAN connection function of the ONU function unit 27 enables the LAN connection using the main signal channel on the OTL 1 and the PON protocol.

  The ONU function unit 27 is a device having a function of connecting to the electrical line 23 in accordance with the protocol specification of the PON interface, and a signal of a predetermined channel corresponding to the ONU function unit 27 among the multi-channels propagating along the electrical line 23 in the downstream direction. In addition, the data is processed and transmitted to the management function unit 26, and the signal transmitted from the management function unit 26 is transmitted in the upstream direction of the electric line 23 through a predetermined channel. Specifically, the ONU function unit 27 is configured as shown in FIG. 2 excluding the optical transceiver 8a from the optical transceiver 8a and the ONU function 8b constituting the ONUs 7-1,... Thus, a channel different from the ONUs 7-1,... 7-n is selected.

In FIG. 2, a PON processing LSI 31 having an input / output unit connected to the electrical signal connection unit 24 includes a first LAN interface 35 including a 10/100 PHY controller 32, a transformer 33, and an RJ 45 connector 34, 10 A second LAN interface 39 including a / 100/1000 PHY controller 36, a transformer 37, and an RJ 45 connector 38, a ZBT-RAM 40, and a data bus 41 are connected. Further, an SRAM 42 and a flash memory 43 are connected to the data bus 41, and a program or the like is stored in the flash memory 43. The RJ25 connectors 34 and 38 are connected to the management function unit 26 via plugs.

  As shown in FIG. 3, the LSI 31 includes an IEEE 802.3ah-compliant MAC (Media Access Control) interface 45 connected to the electrical signal connection unit 24 via a Gigabit serializer / deserializer 44 and a MAC interface 45. An EPON (Ethernet® Passive Optical Network) lookup engine 46 connected to the EPON, and a 10/100 MAC 49 connected to the EPON lookup engine 46 via the switch 47 and the Ethernet® lookup engine 48; 10/100/1000 MAC 51 connected to the EPON lookup engine 46 via the switch 47 and the Gigabit Ethernet (registered trademark) lookup engine 50, and the management interface connected to the MAC interface 45 Interface 52, 80C51 CPU 53, GPIO interface 54, and I2C interface 55 connected to the management interface 52.

  The 10/100 MAC 49 is connected to the 10/100 PHY controller 32, and the 10/100/1000 MAC 51 is connected to the 10/100/1000 PHY controller 36. The 80C51 CPU 53 is connected to the data bus 41 described above.

  Furthermore, the GPIO interface 54 can connect to various devices 25 via the management function unit 26 having a CPU function and collect device signals that are relay device management signals such as alarms. Depending on the type and the number of signals, it is possible to collect device signals as relay device management signals by directly connecting to the GPIO interface 54.

  Similarly, the I2C interface 55 can be connected to various devices 25 via the management function unit 26 having a CPU function to collect device signals that are relay device management signals such as alarms. It is possible to transmit temperature information as a relay device management signal by connecting a temperature sensor (not shown) or the like as various devices 25 via an analog / digital conversion board (not shown) having no CPU function.

  In FIG. 1, reference numeral 59 denotes a supervisor connected to the OTL 1, and reference numeral 60 denotes a monitoring operation device that monitors and operates the optical repeater 4 by inputting and outputting signals to and from the supervisor 59.

  In the optical transmission system described above, the upstream optical signal from the ONUs 7-1,... 7-n to the OLT 1 is propagated as follows.

  Optical signals (burst signals) in the wavelength band of 1.3 μm sent from the ONUs 7-1,..., 7-n are combined by the optical coupler 5 and further transmitted through the optical fibers 6-1,. Propagated to the second EO / OE unit 22 of the relay apparatus 4.

  Further, in the optical repeater 4, the data indicating the operation state of the first and second EO / OE units 21 and 22 and the detection data of various devices 25 are detected by the management function unit 26, and further the ONU function unit 27. Is transmitted to the electrical signal connection unit 24 through a predetermined channel.

  The output signal from the ONU function unit 27 is multiplexed to a predetermined channel of the upstream electrical signal propagating through the electrical line 23 via the electrical signal connection unit 24, and further converted into an optical signal by the first EO / OE unit 21. Is output to the optical fiber 2 and finally received by the OTL 1. Among the optical signals received by the OTL 1, the optical signal of a predetermined channel is stored as monitoring data of the optical repeater 4 in the monitoring operation device 60 via the supervisor 59.

  On the other hand, the downstream optical signal output from the OLT 1 is transmitted to the ONUs 7-1 and 7-n as follows.

  The optical signal having a wavelength of 1.49 μm transmitted from the OLT 1 propagates through the optical fiber 2 and is input to the first EO / OE unit 21 of the optical repeater 4. In addition, the optical repeater monitoring control / setting signal output from the monitoring operation device 60 to the supervisor 59 among the optical signals is output to the fiber 2 through a predetermined channel by the OLT 1.

  An optical signal propagating in the downstream direction through the optical fiber 2 is input to the first EO / OE unit 21, where it is converted into an electric signal and output to the electric line 23, and further the second EO is output by the electric signal connection unit 24. / OE22 and ONU function unit 27 are divided into two routes.

  The ONU function unit 27 takes in an electric signal of a predetermined channel and further outputs it to the management function unit 26. The management function unit 26 controls and controls the devices in the first and second EO / OE units 21 and 22 provided in the optical repeater 4 and the various devices 25 based on the electric signal input from the ONU function unit 27. Perform settings and various detection operations. The control / setting signal includes setting signals for various parameters of the device.

  The electrical signal input from the electrical line 23 to the second EO / OE unit 22 is converted into an optical signal here and output to the optical fiber 3, and further to the plurality of ONUs 7-1 to 7 -n by the optical coupler 5. The signals transmitted and assigned to the respective ONUs 7-1 and 7-n by the ONU function 8b are taken in.

  Note that optical signals are transmitted between the ONUs 7-1, 7-n and the OTL 1 as usual through the optical repeater 4, and connected to the Internet line or the like, or to the CATV center device or the like.

Therefore, when the system function in the above optical transmission system is logically shown, it is as shown in FIG. 4 , and the ONU function unit 27 of the optical repeater 4 is equivalent to the ONU function 8b of the ONUs 7-1,. Since the system can be configured with the protocol specifications, the ONU function unit 27 for the management function can also utilize operations performed between the OTL 1 and the ONUs 7-1,. Therefore, the management of the optical repeater 4 installed in the optical transmission line between the OTL 1 and the ONUs 7-1 and 7-n for the purpose of extending the distance of the PON type optical transmission system can be performed without using a new separate line. In addition, it is possible to efficiently multiplexly accommodate the optical transmission line without affecting the existing operation.

(Second Embodiment)
FIG. 5 is a block diagram showing a configuration of an optical repeater used in an optical transmission system according to the second embodiment of the present invention, and shows a more specific configuration of the optical repeater 4 shown in FIG. Yes. In FIG. 5, the same reference numerals as those in FIG. 1 denote the same elements.

  In FIG. 5, an electrical line 23 connecting the first EO / OE unit 21 and the second EO / OE unit 22 transmits the electrical signal in the upstream direction to the first electrical line 23a that propagates the electrical signal in the downstream direction. A second electric line 23b to be propagated is provided. A first electric signal connection unit 61 that branches an electric signal to the ONU function unit 27 and the drive circuit 68 is connected to the middle of the first electric line 23a. Further, in the middle of the second electric line 23b, a second electric signal connection unit 62 that multiplexes an output electric signal of a predetermined channel output from the ONU function unit 27 into an electric signal in the second electric line 23b. Is connected. For example, a buffer IC is used as the second electric signal connection unit 62.

  The first EO / OE unit 21 receives a first WDM coupler 63 connected to the optical fiber 2 on the OTL 1 side, and a downstream optical signal demultiplexed by the first WDM coupler 63 and converts it into an electrical signal. The first light receiving element 64 to be converted, the first receiving circuit 65 that outputs the output electric signal of the first light receiving element 64 by performing 3R or 2R processing, and the upstream electric power from the second electric line 23b A first drive circuit 66 that outputs a predetermined drive current based on the signal, and light generated by injecting the drive current from the first drive circuit 66 is output to the optical fiber 2 via the first WDM coupler 63. And a light receiving element 67.

The second EO / OE unit 22 includes a second drive circuit 68 that outputs a drive current based on a downward electric signal from the first electric line 23 a and injection of the drive current from the second drive circuit 68. Is transmitted from the optical fiber 3 and the second WDM coupler 70 that outputs the light input from the second light-emitting element 69 to the optical fiber 3 on the subscriber's home side. A second light receiving element 71 that receives an upstream optical signal via the second WDM coupler 70 and converts it into an electric signal, and an output electric signal of the second light receiving element 71 is subjected to 2R or 3R processing. And a second receiving circuit 72 that outputs to the second electric line 23b.

  The first and second WDM couplers 63 and 70 may be circulators or may have a structure in which an isolator is combined with a 3 dB coupler.

  The management function unit 26 and the ONU function unit 27 have the same configuration as in the first embodiment.

  In the optical transmission system including the optical repeater 4 as described above, the optical signal transmitted from the OTL 1 on the center side is propagated through the optical fiber 2 and the first EO / OE unit 21 as shown in FIG. Is input to the first WDM coupler 63 and is received by the first light receiving element 64. When the first light receiving element 64 converts the received optical signal into an electric signal and outputs the electric signal to the first receiving circuit 65, the first receiving circuit 65 performs a 3R process on the electric signal and performs the first process. It outputs to the electric line 23a.

  The electric signal transmitted to the second EO / OE unit 22 via the first electric line 23 a is branched in two directions by the first electric signal connection unit 61, the second drive circuit 68 and the ONU function unit 27. Is done.

  The second driving circuit 68 that inputs the electric signal causes a current to flow through the second light emitting element 69 based on the input electric signal, thereby causing the second light emitting element 69 to emit light at a predetermined wavelength, for example, 1.49 μm. Further, the optical signal output from the second light emitting element 69 is output to the optical fiber 3 through the second WDM coupler 70, further branched by the optical coupler 5, and further optical fibers 6-1,. n is propagated and input to a plurality of ONUs 7-1,.

Further, the ONU function unit 27 for inputting an electric signal selects a predetermined channel from the electric signals input from the first electric signal connection unit 61 and outputs the selected channel to the management function unit 26. Furthermore, the management function unit 26 only controls / sets the output of the receiving circuits 65, 72, etc., based on the signal of a predetermined channel, or controls the temperature of the heaters included in the various devices 25, for example. Instead, a temperature abnormality signal of various devices 25, for example, a temperature sensor , or data of an apparatus door opening / closing sensor is acquired.

  On the other hand, the optical signals output from the plurality of ONUs 7-1,..., 7-n on the subscriber's home side are multiplexed by the optical coupler 5, propagated through the optical fiber 3, and further in the second EO / OE unit 22. The second light receiving element 71 is irradiated through the second WDM coupler 70. The second light receiving element 71 converts the received optical signal into an electrical signal. The converted electric signal is subjected to 2R or 3R processing by the second receiving circuit 72 and is output to the second electric line 23b.

  The electric signal output from the second receiving circuit 72 is transmitted to the first drive circuit 66 of the first EO / OE section 21 via the second electric line 23b. The electrical signal of a predetermined channel is applied from the electrical signal connection unit 62. The electrical signal of the predetermined channel is a signal output from the management function unit 26 via the ONU function unit 27, and is monitored based on detection signals from the various devices 25, the light receiving elements 64 and 71, the reception circuits 65 and 72, and the like. Signal.

  The second drive circuit 66 to which an electric signal propagating in the upward direction through the second electric line 23 b outputs a drive current to the light receiving element 67. The light receiving element 67 into which the drive current is injected converts the electric signal into an optical signal in the 1.3 μm band and outputs it to the first WDM coupler 63.

  Further, the upstream optical signal output from the first WDM coupler 63 propagates through the optical fiber 2 and reaches the OTL 1 on the center side, and the data obtained based on the optical signal is monitored via the supervisor 59. It is monitored by the operating device 60.

According to the optical repeater described above, the first electric signal that transmits the electric signal in the downstream direction of the electric line 23 that electrically connects the first EO / OE unit 21 and the second EO / OE unit 22. A first electric signal connection unit 61 that branches an electric signal is connected to the line 23a, and a second electric signal connection unit 62 that multiplexes the electric signal is connected to the second electric line 23b in the upstream direction.

Therefore, by connecting the ONU function unit 27 to the first and second electric signal connection units 61 and 62 , the system can be used with the same protocol specifications as the ONU function 8b of the ONUs 7-1,. Therefore, the operation performed between the OLT 1 of the PON specification and the ONUs 7-1,. In addition, since the interface for connecting the management signal for managing the optical repeater 4 to the optical transmission line is the ONU function unit 27 that processes an electric signal without providing an optical transceiver, the optical transmission line is used as an optical signal. Compared with the case of connecting to the cable, it is performed with a simple electric configuration, so that the cost can be reduced.

(Third embodiment)
FIG. 6 is a diagram showing an optical transmission system according to the third embodiment of the present invention, where the same reference numerals as those in FIG. 1 denote the same elements.

  6, a plurality of optical repeaters 4-1,..., 4-m having the same structure as the optical repeater 4 shown in FIG. 1 are connected between the OTL 1 and the optical coupler 5 via the optical fiber 2a. By increasing the number, it is possible to further increase the distance of optical transmission.

  According to this, an electric communication line is provided for managing the optical repeaters 4-1,..., 4-m, or an optical transmission line having a wavelength different from that of the optical repeaters 4-1,. It is not necessary to install a separate line dedicated for management as in the case of providing it, and the ONU function unit 27 for electrical signals can multiplex the management signal to the existing PON optical transmission line.

  The ONU function unit 27 in the optical repeaters 4-1,..., 4-m is substantially the same as the ONU function unit 8b of the ONU 7-1,. The configuration is as shown in FIG. 7, and the ONU function unit 27 in the optical repeaters 4-1... 4-m is logically configured with the existing PON protocol specifications. The operations of OTL1, ONU7-1,..., 7-n can be used for each ONU function unit 27 in 4-m.

  The optical signals used by the plurality of optical repeaters 4-1,..., 4-m are set by the ONU function units 27 so that the optical signal channels are different.

  As described above, according to the optical repeater used in the optical transmission system according to the first to third embodiments of the present invention, the ONU used on the subscriber premises side by the ONU function that can be connected by an electric signal. On the other hand, the components such as optical transceivers and couplers that make up the optical fiber and the optical connection can be omitted, while the ONU function unit 27 for management arranged in the optical repeater can be reduced by utilizing existing ONU function design and IC components. Cost reduction can be realized. Further, since the ONU function unit 27 for management is not connected to the optical transmission line with light, the existing OLT and the ONU function unit are connected by electrically connecting the ONU function without damaging the optical allowable loss of the relay. You can take advantage of the operations between.

  Furthermore, according to the optical transmission system using the optical repeater, an optical repeater having an ONU function unit that can be connected by an electrical signal between the center-side OLT and the subscriber premises ONU constituting the PON system. Therefore, the management function such as monitoring and control of the optical repeater can be easily multiplex-connected to the PON line using the PON specification protocol without using a separate line for management. There is an advantage that the management of the network and the management of the optical repeater can be easily integrated.

FIG. 1 is a configuration diagram of an optical transmission system according to the first embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the ONU function unit of the optical repeater used in the optical transmission system according to the first embodiment of the present invention. FIG. 3 is a block diagram showing an LSI configuration of the ONU function unit in the optical repeater used in the optical transmission system according to the first embodiment of the present invention. FIG. 4 is a block diagram showing a relationship with the ONU function viewed from the OLT of the optical transmission system according to the first embodiment of the present invention. FIG. 5 is a block diagram showing a configuration of an optical repeater used in the optical transmission system according to the second embodiment of the present invention. FIG. 6 is a configuration diagram of an optical transmission system according to the third embodiment of the present invention. FIG. 7 is a block diagram showing the relationship with the ONU function viewed from the OLT of the optical transmission system according to the third embodiment of the present invention. FIG. 8 is a side view showing an example of an optical repeater used in a PON type optical transmission system according to the prior art.

Explanation of symbols

1: OLT
2, 3: optical fibers 4, 4-1, ... 4-m: optical repeater 5: optical couplers 6-1, ... 6-n: optical fibers 7-1, ... 7-n: ONU
21 and 22: EO / OE section 23: electrical line 24: electrical signal connection section 25: various devices 26: management function section 27: ONU function section 63, 70: WDM coupler 64, 71: light receiving element 65, 72: receiving circuit 66, 68: drive circuit 67, 69: light emitting element

more than

Claims (4)

An optical repeater used in a PON type optical transmission system in which a center side optical line terminator and one or more subscriber side optical line terminators are connected via a passive type optical transmission line,
A first electrical / optical conversion means connected to the optical transmission line on the center side optical line terminator side for performing photoelectric conversion and reverse photoelectric conversion;
A second electrical / optical conversion means connected to the optical transmission line on the subscriber side optical line termination device side for performing photoelectric conversion and reverse photoelectric conversion;
An electrical signal connecting portion provided in the middle of an electrical transmission path connecting the first electrical / optical converting means and the second electrical / optical converting means;
An ONU function unit connected to the electrical signal connection unit and performing processing in accordance with the protocol of the PON interface;
A management function unit connected to the ONU function unit to perform monitoring control,
The management function unit sends a device signal and a sensor measurement value indicating a state of a predetermined device including the first electric / optical conversion unit and the second electric / optical conversion unit periodically or at a predetermined timing. Input and monitor via the GPIO interface and I2C interface provided in the ONU function unit,
The ONU function unit includes the device signal input from the management function unit and the sensor measurement value in a predetermined channel of an upstream signal input from the subscriber side optical line termination device via the electrical signal connection unit. A repeater management signal is multiplexed and transmitted to the center-side optical line terminator via the electrical signal connection unit. The optical repeater according to claim 1, wherein the predetermined channel is a maintenance channel defined by a PON protocol. The optical repeater according to claim 1 or 2 ,
A center-side optical line terminator connected to the optical repeater by a passive first optical transmission line;
An optical transmission system comprising: one or more subscriber-side optical line terminators connected to the optical repeater by a passive second optical transmission line. The optical transmission system according to claim 3 , wherein a plurality of the optical repeaters are connected via the first optical transmission path or the second optical transmission path.

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