JP2015041882A - Optical receiver and optical communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an easy-to-adjust optical receiver if a plurality of optical transmission lines are existent.SOLUTION: The optical receiver includes: conversion means (PD 101) for converting a record optical signal into an electric signal; adjustment means (ATT 105) for adjusting the signal level of the converted electric signal; detection means (CPU 107) for detecting the signal levels of respective optical signals transmitted through the plurality of optical transmission lines; derivation means (CPU 107) for deriving a set value of the adjustment means according to the detected signal level for each optical transmission line; storage means (memory 109) for storing the derived set value and information to identify the optical transmission line in an associative manner; and setting means (CPU 107) for acquiring, when newly starting the operation of an optical transmission line, the set value corresponding to the optical transmission line from the storage means, and for setting the adjustment means.

Description

  The present invention relates to an optical receiver and an optical communication system.

  In the bidirectional optical transmission device described in Patent Document 1, an electrical signal input to the E / O converter is converted into an optical signal and output from the transmission end. This output signal is sent to one optical fiber line via the 1 × 2 optical switch and propagated to the 2 × 1 optical coupler. The 2 × 1 optical coupler outputs the input propagation signal from the other terminal and transmits it to the receiving end of the O / E converter. The O / E converter converts the input optical signal into an electrical signal and outputs it. When the optical fiber line is disconnected for some reason, this disconnection is detected by the control device, and the connection state of the 1 × 2 optical switch is switched. As a result, the output signal of the E / O converter is transmitted to another optical fiber line, and is propagated to the receiving end of the O / E converter via the 2 × 1 optical coupler.

JP 09-008729 A

  By the way, in the technique disclosed in Patent Document 1, when a failure occurs in one optical transmission line, communication is continued through the other optical transmission line. However, since the transmission distance is different for each optical transmission line or the transmission loss is different, it is necessary to adjust the reception level so that the reception level is appropriate. Since such adjustment needs to be performed for each optical transmission line, there is a problem that it takes time and effort. In particular, when there are a plurality of communication partners, there is a problem that the adjustment is required only by the number of times corresponding to the number of optical transmission lines and the number obtained by the product of the communication partners.

  Therefore, the present invention has been made in view of the above points, and an object thereof is to provide an optical receiver and an optical communication system that can be easily adjusted even when there are a plurality of optical transmission lines. Yes.

In order to solve the above-described problems, the present invention provides an optical receiver that is connected to an optical transmitter by a plurality of optical transmission paths and receives an optical signal transmitted through any of the plurality of optical transmission paths. Conversion means for converting the received optical signal into an electric signal, adjustment means for adjusting a signal level of the electric signal converted by the conversion means, and a signal of the optical signal transmitted through the plurality of optical transmission paths A detecting means for detecting each level, a finding means for finding a set value of the adjusting means corresponding to the signal level detected by the detecting means for each of the optical transmission lines, and the finding means. Storage means for associating and storing the set value and information for specifying the optical transmission line, and when starting operation of a new optical transmission line, the setting corresponding to the optical transmission line Remember the value Obtained from stage has a setting means for setting said adjusting means, the setting means, characterized in that it operates at the time of starting operation of a new optical transmission line.
According to such a configuration, adjustment is easy even when there are a plurality of optical transmission lines.

One aspect of the present invention is that the start of operation of the new optical transmission line is the start of operation of the standby system when switching to the standby optical transmission line due to an abnormality in the active optical transmission line. It is characterized by that.
According to such a configuration, even when the active system is switched to the standby system, the receiving operation can be performed stably.

Further, according to one aspect of the present invention, the detection means extracts a direct current component included in the electrical signal output from the conversion means, and determines the signal level of the optical signal based on the signal level of the direct current component. It is characterized by detecting.
According to such a configuration, it is possible to reliably detect the signal level of the optical signal with a simple configuration.

The present invention also provides an optical communication system in which an optical transmission device and an optical reception device are connected via a plurality of optical transmission lines, wherein the optical reception device converts the received optical signal into an electrical signal. Adjusting means for adjusting the signal level of the electrical signal converted by the converting means; detecting means for detecting the signal level of the optical signal transmitted through the plurality of optical transmission lines; and detecting by the detecting means Obtaining a setting value of the adjusting means according to the signal level determined for each optical transmission line, a setting value obtained by the finding means, and specifying the optical transmission line When starting operation of a new optical transmission line and storage means for storing information in association with each other, the setting value corresponding to the optical transmission line is acquired from the storage means, and the adjustment unit is set And setting means. The features.
According to such a configuration, adjustment is easy even when there are a plurality of optical transmission lines.

According to another aspect of the present invention, the transmission device and the reception device are connected by first and second optical transmission lines, and have a route merging point of the first and second optical transmission lines, and the route The junction includes bypass means for transmitting a part of downstream light transmitted through one of the first and second optical transmission lines in the upstream direction of the other, and the transmission device transmits the first signal to the reception device. Upstream optical transmission means for transmitting upstream light via both the first and second optical transmission lines, and downstream light transmitted from the receiving apparatus via one of the first and second optical transmission lines. And a downstream optical receiving means, wherein the receiving device is configured to select one of the first and second optical transmission lines, and the optical transmission path selected by the selection means. Downstream optical transmission for transmitting the downstream light to a transmission device Out of the downstream light transmitted from the transmission / reception means, the return light returning to the reception apparatus via the bypass means, and the upstream light transmitted from the transmission apparatus by the selection means. Based on the determination results of the first and second transmission paths received from the unselected optical transmission paths and determining the states of the first and second transmission paths from the light states, the selection Control means for performing control for switching the selection state of the means.
According to such a configuration, it is possible to reliably detect an optical fiber abnormality without incurring an increase in cost.

  According to the present invention, it is possible to provide an optical receiver and an optical communication system that can be easily adjusted even when there are a plurality of optical transmission lines.

It is a figure which shows the structural example of the optical communication system which concerns on 1st Embodiment of this invention. It is a figure which shows the structural example of the optical communication apparatus shown in FIG. It is a flowchart for demonstrating an example of operation | movement of 1st Embodiment shown in FIG. It is a flowchart for demonstrating an example of operation | movement of 1st Embodiment shown in FIG. It is a figure which shows the structural example of the optical communication system which concerns on 2nd Embodiment of this invention. It is a figure for demonstrating the detailed structural example of route light SW shown in FIG. It is a figure for demonstrating operation | movement of 2nd Embodiment shown in FIG.

  Next, an embodiment of the present invention will be described.

(A) Description of Configuration of First Embodiment of the Present Invention FIG. 1 is a diagram illustrating a configuration example of an optical communication system according to a first embodiment of the present invention. As shown in this figure, the optical communication system has an optical communication device 1, an optical communication device 2, and an optical transmission path 3.

  Here, the optical communication device 1 is, for example, a center device, converts an RF (Radio Frequency) signal supplied from a higher-level device into an optical signal, and includes an A route and a B route that configure the optical transmission path 3. The data is transmitted to the optical communication apparatus 2 via the active route. The optical communication device 2 is, for example, a node device, receives downstream light transmitted from the optical communication device 1 via the optical transmission path 3, converts it into an RF signal, and supplies it to a lower device. Further, the optical communication device 2 converts, for example, information from a lower device or information indicating the status of the optical communication device 2 into an optical signal, and an active system among the A route and the B route constituting the optical transmission path 3 Is transmitted to the optical communication apparatus 1 via the route. In the example illustrated in FIG. 1, a configuration having only one optical communication device 2 is illustrated. However, for example, a configuration in which a plurality of optical communication devices 2 exist may be used.

  FIG. 2 is a diagram for explaining a detailed configuration example of the optical communication apparatus 1 shown in FIG. As shown in FIG. 2, the optical communication device 1 includes an optical receiving unit 100, a WDM (Wavelength Division Multiplexing) filter 110, an optical transmission unit 111, a redundancy control unit 112, and a route light SW (Switch) 114. Yes.

  Here, the WDM filter 110 multiplexes the downstream light output from the optical transmitter 111 and the upstream light input to the optical receiver 100. The optical transmission unit 111 converts an RF signal supplied from a host device (not shown) into an optical signal and outputs the optical signal to the WDM filter 110.

  The optical receiving unit 100 includes a PD (Photo Diode) 101, an HPF (High Pass Filter) 102, an LPF (Low Pass Filter) 103, an amplification unit 104, an ATT (Attenuator) 105, an amplification unit 106, and a CPU (Central Processing Unit) 107. , A memory SW (Switch) 108, and a memory 109.

  Here, the PD 101 converts the upstream light output from the WDM filter 110 into an electrical signal and supplies the electrical signal to the HPF 102 and the LPF 103. The HPF 102 extracts an RF signal component included in the electrical signal supplied from the PD 101 and supplies the RF signal component to the amplification unit 104. The LPF 103 extracts a direct current component included in the electric signal supplied from the PD 101 and supplies it to the CPU 107. The amplifying unit 104 amplifies the RF signal output from the HPF 102 and outputs the amplified RF signal to the ATT 105. The ATT 105 attenuates the RF signal supplied from the amplification unit 104 by the attenuation amount set by the CPU 107 and outputs the attenuated signal. The amplification unit 106 amplifies the RF signal output from the ATT 105 with a predetermined gain and outputs the amplified signal. The CPU 107 controls each unit based on a program stored in the memory 109.

  The memory SW 108 is operated by an administrator, for example, and notifies the CPU 107 of information corresponding to the operation content. The memory 109 is configured by a semiconductor storage device such as a RAM (Random Access Memory) and a ROM (Read Only Memory), and stores programs executed by the CPU 107 and data.

  The redundancy control unit 112 executes A and B route switching processing. The route light SW14 is configured by, for example, an optical cross switch or the like, and connects either the A route or the B route to the WDM filter 110.

(B) Description of Operation of First Embodiment of the Invention Next, operation of the first embodiment of the present invention will be described. Hereinafter, an operation when the optical communication device 2 is connected for the first time will be described, and then an operation when an abnormality occurs in the route (optical transmission path) will be described.

  First, the operation when the optical communication apparatus 2 is connected to the system for the first time will be described. When the optical communication device 2 is connected to the system and, for example, the A route is selected as an inspection target, the upstream light transmitted from the optical communication device 2 is transmitted through the A route and input to the route light SW14. When the A route is selected as the inspection target, the route light SW14 selects the A route, and therefore the upstream light input from the A route is input from the route light SW14 to the PD 101 via the WDM filter 110. . The PD 101 converts the upstream light input from the WDM filter 110 into a corresponding electrical signal and supplies the electrical signal to the HPF 102 and the LPF 103. The HPF 102 extracts a high frequency component corresponding to the RF signal from the electrical signal output from the PD 101 and supplies the high frequency component to the amplification unit 104. The LPF 103 extracts a low frequency component from the electric signal output from the PD 101 and supplies the low frequency component to the CPU 107. The CPU 107 inputs the DC component supplied from the LPF 103 and converts it into a corresponding digital signal.

  Here, the distance of the optical transmission path may differ depending on the route, and the attenuation amount may differ for each route. For this reason, the signal level of the electrical signal output from the PD 101 may differ depending on the transmission path through which the upstream light passes. In order for the subsequent circuit to operate stably, it is desirable that the signal level of the RF signal output from the amplifier 106 is constant regardless of the path. Therefore, the CPU 107 performs control so that the signal level of the electrical signal output from the amplifying unit 106 is constant regardless of the distance of the optical transmission path and the attenuation amount.

  More specifically, since the low frequency component output from the LPF 103 corresponds to the light intensity of the upstream light, the intensity of the upstream light input via the A route is known based on the magnitude of the output signal of the LPF 103. be able to. Therefore, when the value of the signal output from the LPF 103 is small, it indicates that the optical level of the upstream light is small. In this case, the attenuation amount of the ATT 105 is reduced, and the signal output from the LPF 103 A large value indicates that the upstream light level is high. In this case, the attenuation amount of the ATT 105 is increased. As a result, the signal level of the RF signal output from the ATT 105 becomes an optimum value. The memory 109 stores a table in which the value of the signal output from the LPF 103 is associated with the set value of the ATT 105 for optimizing the RF signal with respect to the value. The CPU 107 acquires the attenuation amount of the ATT 105 corresponding to the signal level output from the LPF 103 from the memory 109 and sets the ATT 105. The set value of the ATT 105 acquired as described above is stored in the memory 109 together with information for specifying the optical transmission path. For example, “A” as information for specifying the optical transmission path and “−5 dB” as the set value of the ATT 105 are stored in the memory 109.

  When the measurement of one optical transmission line (A route in the present example) is completed, the CPU 107 controls the route light SW14 to switch from the A route to the B route. Instead of switching automatically, switching may be performed manually or when the memory SW 108 is operated.

  When the switching of the root optical SW 14 is completed, the set value of the ATT 105 is acquired from the memory 109 with reference to the output from the LPF 103 as in the case described above, and the information for specifying the optical transmission path is stored in the memory 109. Stored. For example, “B” as information for specifying the optical transmission path and “−2 dB” which is the set value of the ATT 105 are stored in the memory 109. When the operation is started, the setting value of the working ATT 105 is acquired from the memory 109 and set in the ATT 105, and the root light SW14 is switched to the working system, for example, the A route side. As a result, the RF signal output from the HPF 102 is adjusted to an appropriate signal level by the ATT 105 and then amplified and output by the amplifying unit 106, so that the subsequent circuit can operate stably. .

  Next, the operation when switching the route will be described. For example, when the active system is the A route, when an abnormality occurs in the A route (for example, when a disconnection occurs), the redundancy control unit 112 detects the occurrence of the abnormality and performs a route switching operation. Run. For example, the redundancy control unit 112 requests the CPU 107 to set the ATT 105 appropriately. First, the CPU 107 acquires information for specifying the route after switching from the redundancy control unit 112. In this example, information (for example, “B”) for specifying the B route is acquired as the route after switching. When the CPU 107 acquires information for specifying the route after switching, the CPU 107 acquires the setting value of the ATT 105 corresponding to the information from the memory 109. For example, in the present example, “−2 dB” described above corresponding to the B route is acquired. The CPU 107 sets the set value of the ATT 105 acquired in this way in the ATT 105. Then, the route light SW14 is controlled to switch from the A route to the B route.

  With the above operation, even when the optical transmission line is switched, the ATT 105 is optimally set based on the information stored in the memory 109. Therefore, the amplification unit 106 sets the level almost the same as before switching. Is output. As a result, even when the optical transmission line is switched, the subsequent circuit can be stably operated.

  Next, an example of processing executed in the embodiment shown in FIG. 2 will be described with reference to FIGS. 3 and 4. FIG. 3 is a flowchart for explaining an example of processing executed when the optical communication apparatus 2 is newly connected. When the processing of this flowchart is started, the following steps are executed.

  In step S11, the redundancy control unit 112 controls the route light SW14 to select the A route. As a result, the A route and the WDM filter 110 are connected.

  In step S12, the optical receiver 100 receives upstream light. More specifically, the PD 101 receives the upstream light output from the WDM filter 110, converts it into a corresponding electrical signal, and outputs it.

  In step S <b> 13, the CPU 107 acquires a DC component indicating the light intensity of the upstream light from the output of the LPF 103.

  In step S14, the CPU 107 obtains an optimum set value of the ATT 105 corresponding to the DC component acquired in step S13. For example, the CPU 107 acquires a setting value corresponding to the DC component from a table stored in advance in the memory 109. In addition, you may make it obtain | require not from a table but from a calculation formula.

  In step S15, the optimum ATT 105 value obtained in step 14 is stored in the memory 109 together with information for specifying the route. For example, the information “A” for specifying the route and “−5 dB” that is the set value of the ATT 105 obtained in step S <b> 14 are associated with each other and stored in the memory 109.

  In step S16, the redundancy control unit 112 controls the route light SW14 to select the B route. As a result, the B route and the WDM filter 110 are connected.

  In step S17, the optical receiver 100 receives upstream light. More specifically, the PD 101 receives the upstream light output from the WDM filter 110, converts it into a corresponding electrical signal, and outputs it.

  In step S <b> 18, the CPU 107 acquires a DC component indicating the light intensity of the upstream light from the output of the LPF 103.

  In step S19, the CPU 107 obtains an optimum set value of the ATT 105 corresponding to the DC component acquired in step S13. For example, the CPU 107 acquires a setting value corresponding to the DC component from a table stored in advance in the memory 109. In addition, you may make it obtain | require not from a table but from a calculation formula.

  In step S20, the optimum ATT 105 value obtained in step 19 is stored in the memory 109 together with information for specifying the route. For example, information “B” for specifying a route and “−2 dB” that is the set value of the ATT 105 obtained in step S 19 are associated with each other and stored in the memory 109.

  Through the above processing, the upstream light intensity of each optical transmission line is detected, the set value of the ATT 105 corresponding to the detected light intensity is obtained, and associated with the information for specifying the optical transmission line and associated with the memory 109. Can be stored.

  Next, processing executed when switching the route will be described with reference to FIG. When the flowchart shown in FIG. 4 is started, the following steps are executed.

  In step S31, the CPU 107 determines whether or not the route has been switched. If it is determined that the route has been switched (step S31: Yes), the process proceeds to step S32, and otherwise (step S31: No) terminates the process.

  In step S32, the CPU 107 identifies the route after switching. For example, when the active system is the A route and the operation is switched to the B route that is the standby system, for example, “B” is specified.

  In step S33, the CPU 107 reads the set value of the ATT 105 corresponding to the identified route. For example, when switching to the B route, the setting value (for example, −2 dB) of the ATT 105 associated with “B” is acquired from the memory 109 as information for specifying the route.

  In step S34, the CPU 107 sets the set value of the ATT 105 acquired in step S33 in the ATT 105. For example, when −2 dB is acquired as the set value for the B route, −2 dB is set in the ATT 105.

  In step S35, the redundancy control unit 112 controls the route light SW14 to execute route switching. In the present example, switching from the A route to the B route is executed. The redundancy control unit 112 may switch the route manually instead of automatically switching the route.

  According to the above processing, when the route is switched, the optimum setting value of the ATT 105 for each route stored in the memory 109 is read and set in the ATT 105. For this reason, even when the optical transmission line is switched, an optimum value is set in the ATT 105, so that the subsequent circuit can be stably operated.

(C) Description of Configuration of Second Embodiment of Present Invention Next, a second embodiment of the present invention will be described. FIG. 5 is a diagram for explaining a configuration example of the second embodiment of the present invention. As shown in FIG. 5, the optical communication system of the present invention has a center device 10, an access system 30, a closure 50, and a node device 70. Here, the center apparatus 10 includes an optical transmission unit (TX) 111, an optical reception unit (RX) 100, a WDM filter 13, a root light SW 14, and a redundancy control unit 112. The optical transmitter 111 converts the downstream RF signal into an optical signal and outputs the optical signal. The optical receiving unit 100 has the same configuration as that in FIG. 2, converts the optical signal output from the WDM filter 13 into an electrical signal, and outputs the electrical signal as an upstream RF signal. The WDM filter 13 multiplexes the downstream optical signal and the upstream optical signal and supplies the multiplexed optical signal to the root optical switch 14. The route light SW 14 selects the A route or the B route according to the control of the redundancy control unit 112 and connects to the WDM filter 13. The redundancy control unit 112 switches the route light SW14 according to the upstream light and the downstream light detected by the route light SW14 and the reception state of the light receiving unit 100.

  The access system 30 includes an optical fiber 31 constituting the A route and an optical fiber 32 constituting the B route. The closure 50 has a line bypass unit 51. The line bypass unit 51 bypasses a part of the downlink signal of one route and supplies it to the other route as an uplink signal. For example, a part of the downstream signal of the A route is bypassed and supplied to the B route as an upstream signal.

  The node device 70 includes a bifurcating unit 71, a WDM filter 72, an optical receiving unit 73, an optical transmitting unit 74, amplification units 75 and 76, a DF (Duplex Filter) 77, and an input / output terminal 78.

  The bifurcating unit 71 multiplexes the downstream light and outputs it to the WDM filter 72, demultiplexes the output of the WDM filter 72, and supplies it to the line bypass unit 51. The WDM filter 72 multiplexes downstream light and upstream light and supplies the multiplexed light to the bifurcating unit 71. The optical receiver 73 converts the optical signal output from the WDM filter 72 into an electrical signal and supplies the electrical signal to the amplifier 75. The amplifying unit 75 amplifies the electric signal supplied from the optical receiving unit 73 and supplies the amplified signal to the DF 77. The DF 77 guides the signal supplied from the amplifier 75 to the input / output terminal 78, separates the signal input from the input / output terminal 78, and guides the signal to the amplifier 76. The input / output terminal 78 outputs a downstream RF signal and an upstream RF signal. The amplifying unit 76 amplifies the uplink RF signal output from the DF 77 and supplies it to the optical transmission unit 74.

  FIG. 6 is a diagram illustrating a detailed configuration example of the root light SW14 illustrated in FIG. As shown in FIG. 6, the route light SW14 includes an optical cross switch 141, a WDM filter 142, a downstream light detection unit 143, an upstream light detection unit 144, and a CPU 145.

  The optical cross switch 141 is controlled by the CPU 145 and selects either a connection indicated by a solid line or a connection indicated by a broken line in the drawing. The WDM filter 142 separates downstream light and upstream light output from the optical cross switch 141 and supplies them to the downstream light detection unit 143 and the upstream light detection unit 144, respectively. The downstream light detector 143 detects downstream light supplied from the WDM filter 142 and outputs it to the CPU 145. The upstream light detection unit 144 detects upstream light supplied from the WDM filter 142 and outputs the upstream light to the CPU 145. The CPU 145 controls the connection state of the optical cross switch 141 based on the outputs of the downstream light detection unit 143 and the upstream light detection unit 144.

(D) Description of Operation of Second Embodiment of Present Invention Next, the operation of the second embodiment of the present invention will be described. In the following, description will be made separately for downlink signals and uplink signals. First, the downlink signal will be described.

  A downstream RF signal from a headend device (not shown) is converted into an optical signal by the optical transmission unit 111 and becomes a downstream optical signal. The downstream optical signal is multiplexed with the upstream optical signal by the WDM filter 13 and input to the root light SW14. The root light SW 14 selects the A route or the B route according to the control of the redundancy control unit 112. For example, when the route light SW14 selects the A route, the downstream optical signal is output to the optical fiber 31 of the A route. The downstream optical signal output to the optical fiber 31 is input to the closure 50. The line bypass unit 51 of the closure 50 outputs most of the optical signal supplied from the optical fiber 31 to the bifurcating unit 71, while bypassing a part of the downstream light transmitted through the optical fiber 31, The light is output to the optical fiber 32 as upstream light.

  Downstream light (return light) output to the optical fiber 32 of the B route is supplied to the route light SW14. The downstream light supplied to the route light SW14 is supplied to the WDM filter 142 via the optical cross switch 141. The WDM filter 142 separates downstream light and upstream light supplied from the optical cross switch 141, and supplies downstream light to the downstream light detection unit 143. The downstream light detection unit 143 detects the intensity of downstream light supplied from the WDM filter 142 and notifies the CPU 145 of the detection result.

  On the other hand, most of the downstream light supplied to the line bypass unit 51 via the optical fiber 31 is supplied to the bifurcating unit 71. The bifurcating unit 71 combines the downstream lights of the A route and the B route and outputs the combined light to the WDM filter 72. In the present example, only the A route is transmitted as the downstream light, so the downstream light of only the A route is supplied to the WDM filter 72.

  Downstream light output from the bifurcating unit 71 is separated by the WDM filter 72 and input to the optical receiving unit 73, where it is converted into an electric signal and supplied to the amplifying unit 75. The amplifying unit 75 amplifies the electrical signal output from the optical receiving unit 73 and supplies the amplified signal to the DF 77. The DF 77 outputs the electrical signal output from the amplification unit 75 from the input / output terminal 78 as a downstream RF signal.

  Next, the uplink signal will be described. The upstream RF signal input to the input / output terminal 78 is separated by the DF 77 and supplied to the amplifying unit 76. The amplifying unit 76 amplifies and outputs the upstream RF signal supplied from the DF 77. The optical transmitter 74 converts the electrical signal supplied from the amplifier 76 into an optical signal and supplies the optical signal to the WDM filter 72. The WDM filter 72 supplies the upstream light output from the optical transmission unit 74 to the bifurcation unit 71. The bifurcating unit 71 demultiplexes the upstream light supplied from the WDM filter 72 and supplies it to the closure 50. The upstream light supplied to the closure 50 is supplied to the root light SW14 via the A route and the B route.

  In FIG. 6, when the optical cross switch 141 is in the connection state indicated by the solid line, the upstream light input to the terminal T2 out of the upstream light supplied to the route light SW14 is output from the terminal T1 via the optical cross switch 141. Is done. The upstream light output from the terminal T1 is input to the optical receiving unit 100 via the WDM filter 13. The redundancy control unit 112 monitors the reception state of the optical receiving unit 100, and determines the states of the A route and the B route according to the reception state and the downstream light and upstream light states.

  In FIG. 6, when the optical cross switch 141 is in the connection state indicated by the solid line, the upstream light input to the terminal T <b> 3 among the upstream light supplied to the root light SW <b> 14 is supplied to the WDM filter 142. The upstream light supplied to the WDM filter 142 is supplied to the upstream light detection unit 144. The upstream light detection unit 144 detects the state of upstream light and notifies the CPU 145 of the detection result.

  FIG. 7 is a diagram illustrating a relationship between a route state and a light detection result. FIG. 7A is a diagram showing the relationship between the route state and the light detection result when the route A is operated. When both the A and B routes are normal, the detection results of the downstream light detection unit 143 and the downstream light detection unit 144 are normal (O), and the reception state of the optical reception unit 100 is also normal (O). is there. The reception state of the optical receiving unit 100 can be determined, for example, based on whether or not the output from the LPF 103 is equal to or greater than a predetermined threshold.

  When the A route is disconnected (or when an abnormality occurs), the downstream light does not reach the closure 52, and therefore the detection result of the downstream light detection unit 143 becomes abnormal (x). Further, when the B route is normal, the upstream light is detected by the upstream light detection unit 144, so that the detection result of the upstream light detection unit 144 is normal (O). Further, when the A route is disconnected, the upstream light does not reach the optical receiving unit 100, so that the detection result of the optical receiving unit 100 is abnormal (x).

  When the B route is disconnected, the downstream light bypassed by the closure 50 does not reach the downstream light detection unit 143, and therefore the detection result of the downstream light detection unit 143 is abnormal (x). Further, when the B route is disconnected, the upstream light does not reach the upstream light detection unit 144, and thus the detection result of the upstream light detection unit 144 becomes abnormal (x). When the A route is normal, the upstream signal reaches the optical receiving unit 100, so that the detection result of the optical receiving unit 100 is normal (O).

  When both the A and B routes are disconnected, none of the signals reach, so the detection results of the downstream light detection unit 143, the upstream light detection unit 144, and the optical reception unit 100 are all abnormal (×). It becomes.

  FIG. 7B is a diagram showing the relationship between the route state and the light detection result when the B route is operated. When the B route is operated, the optical cross switch 141 is in a connection state indicated by a broken line. As a result, when both the A and B routes are normal, the detection results of the downstream light detection unit 143 and the downstream light detection unit 144 are normal (◯), and the reception state of the optical reception unit 100 is also normal ( O).

  When the A route is disconnected, the downstream light only reaches the closure 50, and therefore the detection result of the downstream light detection unit 143 is abnormal (x). Further, when the A route is disconnected, the upstream light does not reach the upstream light detection unit 144, and therefore the detection result of the upstream light detection unit 144 is abnormal (x). Further, when the A route is disconnected, the upstream light reaches the optical receiving unit 100 via the B route, so that the detection result of the optical receiving unit 100 is normal (O).

  When the B route is disconnected, the downstream light does not reach the closure 50, and therefore the detection result of the downstream light detection unit 143 is abnormal (x). Even if the B route is disconnected, the upstream light reaches the light detection unit 144 via the A route, so that the detection result of the upstream light detection unit 144 is normal (O). Further, when the B route is abnormal, the upstream signal does not reach the optical receiving unit 100, and therefore the detection result of the optical receiving unit 100 is abnormal (x).

  When both the A and B routes are disconnected, none of the signals reach, so the detection results of the downstream light detection unit 143, the upstream light detection unit 144, and the optical reception unit 100 are all abnormal (×). It becomes.

  From the above, the presence / absence of a route abnormality can be known from the state of the optical cross switch 141 and the reception states of the downstream light detection unit 143, the upstream light detection unit 144, and the optical reception unit 100. When an abnormality is detected, the CPU 145 controls the optical cross switch 141 and switches the connection, so that the communication between the center device 10 and the node device 70 can be continued.

  In the above description, the determination is made based on the detection results of the downstream light detection unit 143, the upstream light detection unit 144, and the optical reception unit 100. However, when the downstream light detection unit 143 cannot detect the downstream light. , Any one of the A route and the B route can be determined to be abnormal (for example, disconnected). More specifically, the combination is any one of (O, X), (X, O), and (X, X). Note that (,) indicates the state of the A route before the comma and the state of the B route after. In this state, if the upstream light is detected by the upstream light detection unit 144, it can be determined that the standby system is normal, and therefore, when the active system is the A route, it may be (×, ○). I understand. On the other hand, when no upstream light is detected by the upstream light detection unit 144, either (◯, ×) or (×, ×) is set. In that case, it is determined that the optical receiving unit 100 is receiving an uplink signal, and if it is received, it is determined to be (◯, ×), and if it is not received (×, ×) ) Can be determined.

  The above is the operation for detecting the abnormality of the optical transmission line of the second embodiment shown in FIG. 5 and FIG. 6, but the optical receiving unit 100 performs the same operation as that of the first embodiment described above. Thus, the set value of the ATT 105 is obtained according to the attenuation amount of the two optical transmission lines, and this is stored in the memory 109. When the optical transmission line is switched, the setting value corresponding to the optical transmission line after the switching is acquired from the memory 109 and set in the ATT 105. Thereby, since the ATT 105 can be optimally set according to the attenuation amount of the optical transmission line, the signal level of the uplink RF signal can be kept optimal before and after switching of the optical transmission line. As a result, the operation of the subsequent circuit can be stabilized.

(E) Description of Modified Embodiment The above embodiment is an example, and it is needless to say that the present invention is not limited to the case as described above. For example, in each of the above embodiments, the ATT 105 is used as means for adjusting the signal level of the electric signal output from the amplifying unit 104. However, other than this, for example, PIN (P-intrinsic-N A diode attenuator may be used, or a voltage gain controlled amplifier (VGA) may be used.

  In each of the above embodiments, the set value (attenuation amount) of the ATT 105 is stored in the memory 109. However, for example, only the signal level of the electrical signal output from the LPF 103 is stored, and this signal level is stored. The set value of the ATT 105 may be calculated from the above. Further, instead of storing the signal level and the set value, a predetermined reference value may be stored, and a correspondence relationship (for example, deviation) with the reference value may be stored for each transmission path.

  In each of the above embodiments, as a method for obtaining the set value of the ATT 105 from the level of the electrical signal, a table is prepared in the memory 109, and the set value is obtained based on this table. You may make it ask | require based on. Alternatively, the level of the electrical signal in any part of the subsequent stage of the ATT 105 is detected, the ATT 105 is adjusted so that the level of the detected electrical signal becomes a predetermined level, and the value at that time is stored in the memory 109. It may be.

  Further, in each of the above embodiments, as an example of starting the operation of a new optical transmission line, the case of switching from the active system to the standby system has been described as an example. However, for example, when starting the operation of the active system It is also possible to apply the present invention.

  Further, in each of the above embodiments, as illustrated in FIG. 1, the case where there is one optical communication device serving as a communication partner has been described as an example. However, when there are a plurality of optical communication devices serving as communication partners, It is also possible to apply the invention. Even when there are a plurality of optical communication devices as communication partners, the attenuation in the optical transmission path is substantially the same. Therefore, if the setting described above is performed for one optical communication device, the setting is used. Good communication can be performed with other optical communication devices.

  In each of the above embodiments, as shown in FIG. 1, communication is performed from the optical communication apparatus 2 to the optical communication apparatus 1 using an optical signal having one type of wavelength. It is also possible to perform communication using the optical signal. Even when optical signals of a plurality of wavelengths are used in this way, the difference in attenuation due to the wavelength in the optical transmission line is small. Therefore, if one type of wavelength is set as described above, other types of wavelengths are used. There is no need to set the wavelength.

1, 2 Optical communication device 3 Access system 13 WDM filter 14 Route light SW
30 Access system 31 A route 32 B route 50 Closure (route confluence)
51 Line bypass section (bypass means)
70 Node equipment 71 Bifurcation part 72 WDM filter 73 Optical receiving part (downlink optical receiving means)
74 Optical transmitter (upstream optical transmission means)
75,76 Amplifier 77 DF
78 Input / output terminal 100 Optical receiver 101 PD (conversion means)
102 HPF
103 LPF (detection means)
104, 106 Amplifying section 105 ATT (Adjustment means)
107 CPU (detection means, seeking means, setting means)
108 Memory SW
109 memory (storage means)
110 WDM filter 111 optical transmission unit 112 redundancy control unit 114 route optical SW
141 Optical cross switch (selection means)
143 Downstream light detection unit (determination means)
144 Uplink light detection unit (determination means)
145 CPU (determination means, control means)

In order to solve the above problems, the present invention is connected by an optical transmission device and a plurality of optical transmission paths, an optical receiver for receiving optical communication signal transmitted via any of the plurality of optical transmission paths , conversion means and a DC extracting means for extracting a direct current component contained in the converted electric signal by said converting means, an electric signal converted by said converting means for converting an optical communication signal thus received to an electrical signal DC component output signal extracting means for extracting the communication signal is a high frequency component included, the signal level of the optical communication signals transmitted through the plurality of optical transmission path from the DC extracting means Detecting means for detecting each based on the above , attenuating means or amplifying means, the attenuation amount of the attenuating means or the amplification amount of the amplifying means is set as a set value, according to the set value An adjustment unit for adjusting the signal level of the communication signal output from the signal extraction unit with a steady attenuation amount or amplification amount, and a setting value of the adjustment unit according to the signal level detected by the detection unit For each optical transmission path, storage means for associating and storing the setting value obtained by the seeking means and information for specifying the optical transmission path; When starting the operation of a new optical transmission line, the setting unit is configured to obtain the setting value corresponding to the optical transmission line from the storage unit and set the adjustment unit. It is characterized in that it operates when starting operation of a new optical transmission line.
According to such a configuration, adjustment is easy even when there are a plurality of optical transmission lines.

One aspect of the present invention is characterized in that the adjusting means is configured by a variable attenuator or a voltage gain control amplifier.

Further, the present invention provides an optical communication system in which an optical transmission device and an optical reception device are connected via a plurality of optical transmission paths, and an optical communication signal is transmitted via any one of the plurality of optical transmission paths. optical receiving apparatus converts, converting means for converting an optical communication signal thus received to an electrical signal, a DC extracting means for extracting a direct current component contained in the converted electric signal by the converting means, by said converting means a signal extraction means for extracting the communication signal is a high frequency component contained in the electrical signal, a signal level of the optical communication signals transmitted through the plurality of optical transmission path from the DC extracting means detecting means for detecting each based on the DC component to be have a damping means or amplification means, sets the amplification amount of attenuation or the amplifying means of the damping means as a set value, the set value Flip was at steady attenuation or amplification amount, and adjusting means for adjusting the signal level of the communication signal output from said signal extraction means, the adjustment means according to the signal level detected by said detecting means Storage means for determining a setting value for each optical transmission line, storage means for associating and storing the setting value obtained by the seeking means and information for specifying the optical transmission line And a setting unit that acquires the setting value corresponding to the optical transmission line from the storage unit and sets the adjustment unit when starting operation of a new optical transmission line, and setting the setting The means operates when starting operation of a new optical transmission line .
According to such a configuration, adjustment is easy even when there are a plurality of optical transmission lines.

According to another aspect of the present invention, in an optical communication system in which an optical transmission device and an optical reception device are connected via a plurality of optical transmission lines, the optical reception device converts the received optical communication signal into an electrical signal. Converting means for converting; adjusting means for adjusting the signal level of the electrical signal converted by the converting means; detecting means for detecting the signal level of an optical communication signal transmitted through the plurality of optical transmission lines; Finding means for finding the set value of the adjusting means corresponding to the signal level detected by the detecting means for each of the optical transmission lines, the set value obtained by the seeking means, and the optical transmission line Storage means for associating and storing information for specifying, and when starting the operation of a new optical transmission line, the setting value corresponding to the optical transmission line is acquired from the storage means, Setting method for setting the adjustment means When it has, and the light transmitting device wherein the light receiving device is connected by the first and second optical transmission line has a root junction of the first and second optical transmission path, the route merging point, the part of the downstream optical transmitting one of the first and second optical transmission line has a bypass means for transmitting to the other uplink, the optical transmission apparatus, relative to the light receiving device, wherein Upstream optical transmission means for transmitting upstream light via both the first and second optical transmission lines, and downstream light transmitted from the optical receiver via either the first or second optical transmission path anda downstream optical receiver means for receiving, the optical receiver is characterized by having a selection means for selecting one of said first and second optical transmission path.
According to such a configuration, it is possible to reliably detect an optical fiber abnormality without incurring an increase in cost.

Claims (5)

In an optical receiver that is connected to an optical transmitter by a plurality of optical transmission paths and receives an optical signal transmitted through any of the plurality of optical transmission paths,
Conversion means for converting the received optical signal into an electrical signal;
Adjusting means for adjusting the signal level of the electrical signal converted by the converting means;
Detection means for detecting signal levels of optical signals transmitted through the plurality of optical transmission paths,
Obtaining means for obtaining a set value of the adjusting means according to the signal level detected by the detecting means for each optical transmission line;
Storage means for storing the setting value obtained by the obtaining means and information for specifying the optical transmission path in association with each other;
When starting operation of a new optical transmission line, the setting value corresponding to the optical transmission line is acquired from the storage unit, and setting means for setting the adjustment unit,
The optical receiving apparatus, wherein the setting means operates when starting operation of a new optical transmission line. 2. The start of operation of the new optical transmission line is the start of operation of the standby system when switching to the standby optical transmission line due to an abnormality in the active optical transmission line. The optical receiver described. The detection means extracts a DC component contained in an electrical signal output from the conversion means, and detects the signal level of the optical signal based on the signal level of the DC component. The optical receiver according to 1 or 2. In an optical communication system in which an optical transmission device and an optical reception device are connected via a plurality of optical transmission lines,
The optical receiver is
Conversion means for converting the received optical signal into an electrical signal;
Adjusting means for adjusting the signal level of the electrical signal converted by the converting means;
Detecting means for detecting a signal level of an optical signal transmitted through the plurality of optical transmission lines;
Obtaining means for obtaining a set value of the adjusting means according to the signal level detected by the detecting means for each optical transmission line;
Storage means for storing the setting value obtained by the obtaining means and information for specifying the optical transmission path in association with each other;
When starting operation of a new optical transmission line, the setting value corresponding to the optical transmission line is obtained from the storage means, and setting means for setting the adjustment means;
An optical communication system comprising: The transmitting device and the receiving device are connected by first and second optical transmission lines, and have a route merge point of the first and second optical transmission lines,
The route junction has bypass means for transmitting a part of downstream light transmitted through one of the first and second optical transmission lines in the other upstream direction,
The transmitter is
Upstream optical transmission means for transmitting upstream light to the receiver via both the first and second optical transmission lines;
A downstream light receiving means for receiving downstream light transmitted from the receiving device via one of the first and second optical transmission lines,
The receiving device is:
Selecting means for selecting one of the first and second optical transmission lines;
Downstream optical transmission means for transmitting the downstream light to the transmission device via the optical transmission path selected by the selection means;
Of the downstream light transmitted from the transmission / reception means, the selection means selects the return light returning to the reception device via the bypass means and the upstream light transmitted from the transmission device. Determining means for receiving via a non-side optical transmission line and determining the state of the first and second transmission lines from the state of these lights;
Control means for performing control to switch the selection state of the selection means based on the determination result of the determination means,
The optical communication system according to claim 4.

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