JP2013074319A - Optical transmission system and optical repeater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical transmission system that takes fault countermeasures with simpler constitution than before, and has higher robustness than before.SOLUTION: An optical closure 120 is connected to a center 110 in a multiple-connection manner through a plurality of optical transmission lines, repeats an optical signal transmitted from the center 110, and outputs the optical signal to a drop closure 130. Once a break of transmission of the optical signal of T.Line#0 is detected, an optical switch 200 switches an optical transmission line used to transmit the optical signal to the center 110 to T.Line#1.

Description

  The present invention relates to an optical transmission system used as an access network. The present invention also relates to an optical repeater included in such an optical transmission system.

  In recent years, FTTH (Fiber To The Home) has become widespread as an access network connecting the center and each home. The FTTH is an access network in which the transmission path from the center to each home is all-optical, and can provide a high-speed and broadband broadcasting / communication environment. In FTTH, a trunk optical fiber drawn from the center is usually branched by an optical splitter stored in a closure and drawn into each home. Thus, the point-to-multi-point FTTH realized using an optical splitter is called a PON (Passive Optical Network) because the optical splitter is a passive element.

  The PON is a robust system in which a failure due to a failure is unlikely to occur because the transmission path is composed only of an optical fiber and an optical splitter. However, when a failure such as disconnection occurs in the trunk optical fiber connecting the center and the optical splitter, it affects all households connected to the optical splitter, and a great deal of restoration work such as re-laying the trunk optical fiber. It takes time. Therefore, when it is applied to a system that does not allow interruption of broadcasting / communication over a long period of time such as CATV (Cable Television, Common Antenna Television, Community Antenna Television), countermeasures such as redundancy of trunk optical fibers are taken. I need it.

  For example, Patent Document 1 discloses an optical transmission system in which a transmission route (corresponding to the trunk optical fiber described above) for transmitting a downstream optical signal from the center to an optical passive component (corresponding to the optical splitter described above) is made redundant. Yes. This optical transmission system is configured to automatically switch the transmission route of the downstream optical signal from the operating system to the non-operating system when the monitoring level of the downstream optical signal decreases.

JP 2010-81492 A

  However, in the optical transmission system described in Patent Literature 1, the transmission route of the downstream optical signal is switched by the optical switch on the center side, and the downstream optical signal that has reached the optical passive component needs to be fed back to the center side. . For this reason, in the optical transmission system described in Patent Document 1, the optical passive component is configured by a 2 × 2 optical coupler, and an optical signal output from one port of the 2 × 2 optical coupler is used as an operational system and a non-operational system. A configuration that feeds back to the center side through the transmission route of the system is adopted. For this reason, it is necessary to provide an optical fiber for transmitting the downstream optical signal and an optical fiber for transmitting the upstream optical signal for each of the operational and non-operational transmission routes. There was a problem of hanging.

  Further, in the optical transmission system disclosed in Patent Document 1, when a failure occurs in the configuration for feedback, a failure in the optical transmission route cannot be detected or no failure occurs in the optical transmission route. Therefore, the output system from the downstream optical transmitter is automatically switched to the other optical transmission route.

  As described above, the conventional optical transmission system has a problem that the configuration is complicated for the countermeasure against the failure, and the robustness is impaired by the complicated configuration.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to realize a more robust optical transmission system by taking measures against failures with a simpler configuration.

  In order to solve the above-described problems, an optical transmission system according to the present invention is connected to a center and two or more optical transmission lines that transmit optical signals transmitted from the center, and any of the two or more optical transmission lines is connected. An optical transmission system including an optical repeater that relays an optical signal transmitted through the optical repeater, wherein the optical repeater transmits or receives an optical signal normally through the first optical transmission line. Detecting means for detecting whether or not an optical signal is normally transmitted through the first optical transmission line, the optical transmission line to be relayed is detected when the detection means detects that the optical signal is not normally transmitted through the first optical transmission line. And an optical switch for switching from the optical transmission line to the second optical transmission line.

  According to the above configuration, even if some failure occurs in the first optical transmission line, this is immediately detected, and the optical transmission line used for transmitting the optical signal is switched to the second optical transmission line. Thus, the optical signal can be continuously transmitted.

  In particular, since it is not necessary to provide a configuration for switching the optical transmission path on the center side, a configuration for feeding back an optical signal from the optical repeater to the center is not required. Therefore, it is possible to realize an optical transmission system that is simpler than the conventional one and more robust than the conventional one.

  In the optical transmission system, it is preferable that the optical signals transmitted from the center and transmitted through the two or more optical transmission paths are the same optical signal.

  According to this configuration, switching of the optical transmission path can be realized without performing an operation of switching the optical transmission path connected to the optical transmitter on the center side.

  In the optical transmission system, the optical signal transmitted from the center and transmitted through the two or more optical transmission lines includes a monitoring signal light having a specific wavelength, and the detection means includes: It is preferable to detect whether or not the monitoring signal light is normally transmitted through the first optical transmission line.

  According to this configuration, even if the optical signal for data transmission is a discontinuous optical signal, for example, some failure occurs in the optical transmission line by detecting that the monitoring optical signal is interrupted. Can be detected.

  In the optical transmission system, the optical switch switches the optical transmission line to be relayed from the first optical transmission line to the second optical transmission line, and then transmits the optical signal through the first optical transmission line. When the detection means detects that the signal is normally transmitted, it is preferable to switch the optical transmission line to be relayed from the second optical transmission line to the first optical transmission line.

  According to this configuration, the optical signal transmitted through the second optical transmission line is relayed only when the optical signal is not normally transmitted through the first optical transmission line. Therefore, it is effective when the second optical transmission line is a spare optical transmission line or when the function and performance are inferior to those of the first optical transmission line.

  In the optical transmission system, the detection means is configured to determine whether the optical signal is normal via the second optical transmission line in addition to whether the optical signal is normally transmitted via the first optical transmission line. The optical switch switches the optical transmission line to be relayed from the first optical transmission line to the second optical transmission line, and then the second optical transmission line. When it is detected that the optical signal is not normally transmitted through the optical transmission line, the optical transmission line to be relayed is preferably switched from the second optical transmission line to the first transmission line.

  According to this configuration, the optical transmission line to be relayed is switched when the optical signal is not normally transmitted in the first optical transmission line and when the optical signal is normal in the second optical transmission line. Only when it is no longer transmitted. Therefore, it is effective when it is desired to reduce the number of times the optical transmission line to be relayed is switched.

In the optical transmission system, it is preferable that the optical repeater further includes a photoelectric conversion unit, and operates with electric power generated by the photoelectric conversion unit. According to this configuration, the optical repeater is externally powered. Therefore, the configuration of the optical transmission system can be simplified. The photoelectric conversion means may generate electric power from sunlight, or may generate electric power from light transmitted from an optical fiber such as signal light.

  The optical repeater included in the optical transmission system according to the present invention is also included in the scope of the present invention.

  According to the present invention, since it is possible to take a countermeasure against a failure with a simpler configuration than before, it is possible to realize an optical transmission system that is more robust than before.

1 is a diagram illustrating an overall configuration of an optical transmission system according to a first embodiment. It is a figure which shows the structure of the center which concerns on Embodiment 1. FIG. 1 is a diagram illustrating a configuration of an optical closure according to a first embodiment. It is a flowchart which shows an example of the procedure of the switching process of the optical switch by a control circuit. It is a flowchart which shows another example of the procedure of the switching process of the optical switch by a control circuit. 6 is a diagram illustrating a configuration of an optical closure according to a second embodiment. FIG. 6 is a diagram illustrating a configuration of an optical closure according to a third embodiment. FIG. It is a figure which shows the structure of the optical closure which concerns on Embodiment 4. FIG. FIG. 10 is a diagram illustrating a configuration of an optical closure according to a fifth embodiment. FIG. 10 is a diagram illustrating a configuration of an optical closure according to a sixth embodiment. It is a figure which shows the modification of the optical closure which concerns on Embodiment 3. FIG. It is a figure which shows the modification of the optical closure which concerns on Embodiment 6. FIG.

Embodiment 1
A first embodiment of the present invention (hereinafter also referred to as “Embodiment 1”) will be described with reference to FIGS. 1 and 2.

(Outline of optical transmission system)
First, an outline of the optical transmission system 10 according to the first embodiment will be described. FIG. 1 is a diagram illustrating an overall configuration of an optical transmission system 10 according to the first embodiment. As illustrated in FIG. 1, the optical transmission system 10 includes a center 110, an optical closure 120 (optical repeater), and a plurality of optical drop closures 130.

  The optical transmission system 10 is incorporated as a PON type FTTH in a communication system such as an Internet line or a CATV system. In such a communication system, a transmission function of various transmission data (Internet data, CATV data, call data, etc.). Is responsible for.

  In this optical transmission system 10, an optical signal is used as a transmission medium for various transmission data, and an optical fiber is used as a transmission path (optical transmission path). In particular, a single optical fiber is used as an optical transmission line.

  In particular, this optical transmission system 10 uses an optical closure 120 (optical splitter) to branch an optical transmission path between a center 110 (OLT) and an optical line termination unit (ONU) provided in a subscriber's home. Therefore, a PDS (Passive Double Star) system in which the center 110 and the optical line terminator are connected one-to-many is adopted.

  Of course, the optical transmission system 10 can also perform bidirectional communication. For example, the optical transmission system 10 can transmit an optical signal (hereinafter referred to as “downstream optical signal”) from the center 110 to an optical line terminating device provided in a contractor's house. On the contrary, it is possible to transmit an optical signal (hereinafter referred to as “upstream optical signal”) from the optical line terminating device to the center 110. In particular, in the optical transmission system 10, it is possible to simultaneously transmit the downstream optical signal and the upstream optical signal by changing the wavelengths. For example, an optical signal having a wavelength of 1480 nm to 1580 nm is used as the downstream optical signal, and an optical signal having a wavelength of 1260 nm to 1360 nm is used as the upstream optical signal. In each drawing, an optical transmission line, that is, a transmission line through which an optical signal is transmitted is indicated by a dotted arrow. In particular, in FIG. 2 and subsequent figures, optical transmission lines that are downstream optical signal transmission paths are indicated by right-pointing dotted arrows, but as described above, these optical transmission paths can also be upstream optical signal transmission paths.

(center)
The center 110 functions as an optical transmitter that transmits downstream optical signals corresponding to various transmission data. The center 110 is installed, for example, in a communication company station or a CATV company station.

  The center 110 is connected to the optical closure 120 via an optical transmission line (T. Line). In particular, in the example shown in FIG. 1, the center 110 is multiplex-connected to the optical closure 120 via a plurality of optical transmission lines (T. Line # 0 and T. Line # 1). That is, the optical transmission path between the center 110 and the optical closure 120 is duplexed.

  In response to this, the center 110 can transmit the downstream optical signal to the optical closure 120 from each of the plurality of optical transmission lines.

  Actually, a plurality of optical closures 120 are connected to the center 110, and each of them is multiplexed with the center 110, but only one of them is illustrated here.

(Light closure)
The optical closure 120 functions as an optical repeater that relays the downstream optical signal transmitted from the center 110 and outputs it to the optical drop closure 130. The optical closure 120 is installed in an aerial cable disposed between the center 110 and the optical drop closure 130, for example. In general, the optical closure is installed on a utility pole or an overhead cable. For this reason, in this embodiment, although the installation place of the optical closure 120 is made an aerial cable, it is not particularly limited to this.

  As described above, the center 110 and the optical closure 120 are multiplex-connected by a plurality of optical transmission paths, and the center 110 transmits a downstream optical signal to the optical closure 120 from each of the plurality of optical transmission paths. Can do. That is, the downstream optical signal is supplied to the optical closure 120 from each of the plurality of optical transmission lines.

  Therefore, the optical closure 120 uses any one of a plurality of optical transmission paths as an input path for downstream optical signals (that is, an optical transmission path used for transmitting optical signals with the center 110). Then, the optical closure 120 outputs the downstream optical signal transmitted from the optical transmission path as the input path to the optical drop closure 130.

  The optical closure 120 determines which of a plurality of optical transmission paths is set as the input path based on the initial setting, the transmission state of each optical transmission path, and the like.

  In the example shown in FIG. 1, a plurality of optical drop closures 130 (drop closures # 0 to #i) are connected to the optical closure 120 through a plurality of optical transmission lines (B. Lines # 0 to #i). . In response to this, the optical closure 120 can branch the downstream optical signal transmitted from the center 110 and output it to each of the plurality of optical drop closures 130 via the plurality of optical transmission paths. .

(Light drop closure)
When receiving the downstream optical signal output from the optical closure 120, the optical drop closure 130 further branches the received downstream optical signal and outputs it to each of the plurality of optical line terminators. For example, the downstream optical signal output from the optical drop closure 130 is transmitted via a drop cable to a V-ONU (video optical line terminating device) or D-ONU (data for data) provided in the subscriber's house Transmitted to the optical line terminal unit). For this reason, the optical drop closure 130 is installed, for example, on an aerial cable near the contractor's house.

  Each contractor's house can access the Internet from an Internet terminal via such an optical transmission system 10 or receive video data of CATV broadcasts by a television receiver.

(Center structure)
Next, the configuration of the center 110 will be described with reference to FIG. FIG. 2 is a diagram illustrating a configuration of the center 110 according to the first embodiment.

  As shown in FIG. 2, the center 110 includes an optical transmitter 112, an optical amplifier 114, and an optical distributor 116. The devices provided in the center 110 including these may be collectively referred to as headend equipment.

  The optical transmitter 112 generates a downstream optical signal corresponding to the transmission data, and outputs the generated downstream optical signal.

  The optical amplifier 114 amplifies the downstream optical signal output from the optical transmitter 112 and outputs the amplified downstream optical signal.

  The optical distributor 116 distributes the downstream optical signal output from the optical amplifier 114 to a plurality of output destinations. In the example illustrated in FIG. 2, the optical distributor 116 is configured to distribute the downstream optical signal amplified by the optical amplifier 114 into two and output the signals to each of the two optical closures 120.

  In practice, a plurality of optical distributors 116 are connected to each of the optical amplifiers 114 in a one-to-many manner depending on the number of optical closures 120 that are transmission destinations of downstream optical signals. Only one of them is illustrated.

  Here, in the center 110 of this embodiment, the transmission system of the downstream optical signal to the optical closure 120 is duplexed, and the optical transmitter 112, the optical amplifier 114, and the optical distributor 116 are respectively provided for each transmission system. Is provided.

  For example, in the example shown in FIG. 2, T.B. is one optical transmission line that connects the center 110 and the optical closure 120. An optical transmitter # 0, an optical amplifier # 0, and an optical distributor # 0 are provided in the downstream optical signal transmission system # 0 for Line # 0.

  Further, the other optical transmission path connecting the center 110 and the optical closure 120 is T.I. An optical transmitter # 1, an optical amplifier # 1, and an optical distributor # 1 are provided in the downstream optical signal transmission system # 1 for the Line # 1.

  As described above, the center 110 of the present embodiment is configured so that the transmission system of the downstream optical signal with respect to the optical closure 120 is duplicated, so that even if a failure occurs in one transmission system, the transmission system from the other transmission system. The downstream optical signal can be transmitted to the optical closure 120.

  In particular, each transmission system has its own set of components (optical transmitter, optical amplifier, and optical distributor), so even if one transmission system fails, the path is switched, etc. Without performing this control, the downstream optical signal can be transmitted to the optical closure 120 from the other transmission system. Therefore, the configuration of the center 110 can be simplified.

  Furthermore, the center 110 of the present embodiment employs a configuration in which the same downstream optical signal is transmitted in parallel from the above two transmission systems. Thereby, even if a failure occurs in one transmission system, the same downstream optical signal can be transmitted to the optical closure 120 from the other transmission system without performing any control such as switching. For this reason, the center 110 according to the present embodiment can continuously transmit the transmission data transmitted from one transmission system before the occurrence of the failure from the other transmission system after the occurrence of the failure.

(Configuration of optical closure)
Next, the configuration of the optical closure 120 will be described with reference to FIG. FIG. 3 is a diagram illustrating a configuration of the optical closure 120 according to the first embodiment.

  As shown in FIG. 3, the optical closure 120 of this embodiment includes an optical switch 200, a control circuit 210, an optical distributor 220, a photovoltaic power generation panel 232, and a storage battery 234.

(Optical switch)
The optical switch 200 is for switching the input path of the downstream optical signal transmitted from the center 110.

  Specifically, in the example shown in FIG. 3, the input side (center 110 side) port of the optical switch 200 is connected to the T.P. Line # 0 and T.W. Line # 1 is connected. The optical switch 200 includes T.W. Line # 0 and T.W. The same downstream optical signal is transmitted from each of Line # 1.

  The optical switch 200 uses the T.D. Line # 0 or T.W. Switch to any of Line # 1. As a result, the optical switch 200 outputs a downstream optical signal transmitted from one of the optical transmission paths that is set as the input path.

  For example, if the input path is T.P. When switched to Line # 0, the port on the output side (optical drop closure 130 side) of the optical switch 200 is connected to T.P. The downstream optical signal transmitted from Line # 0 is output. Conversely, if the input path is T.P. When switched to Line # 1, the output side port of the optical switch 200 is connected to T.P. The downstream optical signal transmitted from Line # 1 is output. Here, when an optical coupler is employed instead of the optical switch 200, T.I. Line # 0 and T.W. Since the lengths of the transmission lines of Line # 1 are different, even if the same optical signal is transmitted from each optical transmission path, the optical signal may be distorted when combined in the optical closure 120. In order to avoid such a problem, this embodiment employs an optical switch 200 instead of an optical coupler.

(Type of optical switch)
The optical switch 200 employs MEMS (Micro Electro Mechanical Systems) in order to achieve low power consumption, but is not limited to this, and employs a mechanical optical switch, a waveguide optical switch, or the like. You can also.

  As the optical switch 200, a single stable relay (monostable relay) or a latching relay (bistable relay) can be employed.

  The single stable relay is one that is maintained in a predetermined state when the power supply is interrupted. For example, if the input path is T.P. When the state switched to Line # 0 is set to a predetermined state, when the power supply is cut off, the single stable relay has an input path of T.P. The state switched to Line # 0 is held. At this time, the input path is T.P. If the state is switched to Line # 1, the input path is set to T.P. Switch to Line # 0 and the input path is T. If the state is switched to Line # 0, the state is maintained.

  This single stable relay is, for example, a T.S. This is effective when the use of Line # 0 is predetermined.

  On the other hand, the latching relay is one that maintains the state at that time when the power supply is interrupted. For example, if the input path is T.P. If the power supply is cut off while switching to Line # 0, the latching relay has the input path as it is. The state of switching to Line # 0 is maintained, and the input path is T.0. If the power supply is cut off while switching to Line # 1, the input path remains as it is. The state switched to Line # 1 is held.

  This single stable relay is effective, for example, when it is decided in advance that the immediately preceding optical transmission line is used as it is when the power supply is interrupted.

(Control circuit)
The switching operation of the optical switch 200 described above is controlled by the control circuit 210. Specifically, when the control circuit 210 detects that the transmission of the optical signal from one optical transmission path as the input path is interrupted (hereinafter referred to as “transmission interruption”), the control circuit 210 changes the input path. The optical switch 200 is controlled to switch to another optical transmission line.

  For example, T.W. When Line # 0 is the input path, the control circuit 210 performs the T.P. When transmission interruption of the optical signal from Line # 0 is detected, the input path is changed to T.30. The optical switch 200 is controlled so as to switch to Line # 1.

  Conversely, T.W. When Line # 1 is used as an input path, the control circuit 210 executes the T.P. When transmission interruption of the optical signal from Line # 1 is detected, the input path is set to T.P. The optical switch 200 is controlled to switch to Line # 0.

  The control circuit 210 has a function of issuing a warning when a transmission interruption of an optical signal is detected. For example, when a transmission interruption of an optical signal is detected, the control circuit 210 turns on an LED provided in the optical closure 120, notifies an external device by communication such as Wi-Fi, or a latching type relay. Is used as contact information, and the administrator can appropriately extract the contact information.

(Configuration for detecting optical signal transmission interruption)
The optical closure 120 further includes optical couplers 242, 244, 246, and detection circuits 252, 254, 256 as a configuration for detecting transmission interruption of the optical signal.

  The optical coupler 242 (optical coupler # 0) It is provided on the path of Line # 0. The optical coupler 242 is a T.W. The downstream optical signal transmitted from Line # 0 is distributed to the detection circuit 252 (detection circuit # 0). Based on the supply of the optical signal from the optical coupler 242, the detection circuit 252 detects the T.P. A transmission interruption of the downstream optical signal transmitted from Line # 0 is detected. For example, if the downstream optical signal has not been supplied from the optical coupler 242 for a predetermined time or more, the detection circuit 252 detects that the T.D. This is detected as a transmission interruption of the downstream optical signal transmitted from Line # 0. When detecting the transmission interruption, the detection circuit 252 notifies the control circuit 210 accordingly.

  With this notification, the control circuit 210, for example, Line # 0 or T. In the transmission system of the optical signal to Line # 0, it can be detected that some kind of failure has occurred.

  The optical coupler 244 (optical coupler # 1) It is provided on the path of Line # 1. The optical coupler 244 is a T.W. The downstream optical signal transmitted from Line # 1 is distributed to the detection circuit 254 (detection circuit # 1). Based on the supply of the optical signal from the optical coupler 244, the detection circuit 254 detects the T.P. The transmission interruption of the downstream optical signal transmitted from Line # 1 is detected. For example, if the optical signal is not supplied from the optical coupler 244 for a predetermined time or longer, the detection circuit 254 detects the T.D. This is detected as a transmission interruption of the downstream optical signal transmitted from Line # 1. When detecting the transmission interruption, the detection circuit 254 notifies the control circuit 210 to that effect.

  With this notification, the control circuit 210, for example, Line # 1 or T. In the transmission system of the optical signal to Line # 1, it can be detected that some kind of failure has occurred.

  The optical coupler 246 (optical coupler # 2) is provided on the path on the output side (optical drop closure 130 side) of the optical switch 200. The optical coupler 246 distributes the downstream optical signal output from the optical switch 200 to the detection circuit 256 (detection circuit # 2). The detection circuit 256 detects transmission interruption of the downstream optical signal from the optical switch 200 based on the supply of the optical signal from the optical coupler 246. For example, when an optical signal is not supplied from the optical coupler 246 for a predetermined time or more, the detection circuit 256 detects this as a transmission interruption of the downstream optical signal from the optical switch 200. When detecting the transmission interruption, the detection circuit 256 notifies the control circuit 210 to that effect.

  By this notification, for example, the control circuit 210 can detect that some failure has occurred in the optical switch 200.

  For example, each of the optical couplers 242, 244, 246 has a branching ratio of about 100 (optical switch / optical distributor side): 1 (detection circuit side). As described above, by using each of the optical couplers 242, 244, and 246 having a small intensity on the detection circuit side, it is possible to minimize loss due to the branching of the optical signal.

  By connecting the input and output of each optical coupler in reverse, each detection circuit can detect the supply interruption of each upstream optical signal.

  For example, by connecting the input and output of the optical coupler 242 in the opposite direction, the detection circuit 252 is connected to the optical switch 200 from the optical switch 200. It is possible to detect the supply interruption of the upstream optical signal output to Line # 0 and notify the control circuit 210 of the supply interruption of the upstream optical signal.

  By this notification, for example, the control circuit 210 transmits the upstream optical signal to the T.P. Regarding the function of transmitting to Line # 0, it is possible to detect that some failure has occurred in the optical switch 200.

  Further, by connecting the input and output of the optical coupler 244 in the opposite direction, the detection circuit 254 is connected to the optical switch 200 from the optical switch 200. It is possible to detect the supply interruption of the upstream optical signal output to Line # 1 and notify the control circuit 210 of the supply interruption of the upstream optical signal.

  By this notification, for example, the control circuit 210 transmits the upstream optical signal to the T.P. With respect to the function of transmitting to Line # 1, it is possible to detect that some failure has occurred in the optical switch 200.

  Further, by connecting the input and output of the optical coupler 246 in the opposite direction, the detection circuit 256 detects the supply interruption of the upstream optical signal input to the optical switch 200 from the downstream optical transmission line, and the upstream optical signal The supply interruption can be notified to the control circuit 210.

  By this notification, for example, the control circuit 210 detects that some failure has occurred in the optical transmission path on the downstream side or in the transmission system of the optical signal to the optical transmission path on the downstream side of the optical switch 200. be able to.

(Light distributor)
An optical distributor 220 is connected to the output side port of the optical switch 200. As a result, the downstream optical signal output from the optical switch 200 is output to the optical distributor 220.

  A plurality of optical transmission lines (B. Lines # 0 to #i) are connected to the output side port of the optical distributor 220. The optical distributor 220 receives the downstream optical signal output from the optical switch 200. The optical distributor 220 can distribute the received downstream optical signal and output it to each of the plurality of optical transmission lines (B. Lines # 0 to #i).

(Light closure power supply)
Next, the power supply of the optical closure 120 will be described. The optical closure 120 further includes a solar power generation panel 232 and a storage battery 234 as a power source.

  As already described, the optical closure 120 is installed in a relatively high place such as an overhead cable. That is, the light closure 120 is installed in a place where it is easy to receive sunlight.

  In response to this, the photovoltaic power generation panel 232 is disposed in the light closure 120 such that the light receiving surface is exposed to the outside of the light closure 120.

  Thereby, the solar power generation panel 232 can generate electric power by receiving sunlight and performing photoelectric conversion using the sunlight.

  The light closure 120 (particularly the control circuit 200) can be operated by the power generated by the photovoltaic power generation panel 232.

  The electric power generated by the photovoltaic power generation panel 232 can be stored in a storage battery 234 such as a lithium ion secondary battery.

  Thereby, for example, when the amount of power generated by the solar power generation panel 232 is sufficient, such as in the daytime, the optical closure 120 operates with the electric power generated by the solar power generation panel 232 and charges the storage battery 234, for example, at night. When the amount of power generated by the solar power generation panel 232 is insufficient, the operation can be performed with the electric power stored in the storage battery 234.

  As described above, the optical closure 120 according to the first embodiment includes the photovoltaic power generation panel 232 that autonomously generates power, and adopts a configuration that operates using the power generated by the photovoltaic power generation panel 232. Therefore, the optical switch 200 can be provided in the optical closure 120 without requiring supply to the optical closure 120 of an external power source such as AC100V, which has been difficult in the past.

  In addition, since it is not necessary to supply power to the optical closure 120, the amount of external power supplied to the optical transmission system 10 can be reduced.

  In addition, since the optical closure 120 can be installed even in a place where a power supply power line cannot be installed, restrictions on the installation location of the optical closure 120 can be relaxed.

  In addition, for example, even when a power failure occurs, the power transmission system 10 can be stably operated because it can continue to operate using the power generated by the photovoltaic power generation panel 232.

(Example of switching procedure)
Next, with reference to FIG. 4, an example of the procedure of the switching process of the optical switch 200 by the control circuit 210 will be described. FIG. 4 is a flowchart illustrating an example of a procedure for switching processing of the optical switch 200 by the control circuit 210.

  Here, when the transmission interruption of the downstream optical signal from the default optical transmission line (T.Line # 0) is detected, the input path is switched to another optical transmission line (T.Line # 1), and then An example in which the input path is switched to the default optical transmission path when transmission of the downstream optical signal from the default optical transmission path is restored will be described.

  First, the control circuit 210 sets the input path to the T.C. Switch to Line # 0 (step S402).

  Thereafter, the control circuit 210 performs T.P. It is determined whether or not transmission interruption of the optical signal from Line # 0 has been detected (step S404).

  If it is determined in step S404 that transmission interruption of the optical signal has not been detected (step S404: No), the control circuit 210 continues the determination process of step S404.

  On the other hand, if it is determined in step S404 that transmission interruption of the optical signal has been detected (step S404: Yes), the control circuit 210 advances the process to step S406.

  In step S406, the control circuit 210 performs T.P. It is determined whether or not transmission interruption of the optical signal from Line # 1 has been detected (step S406).

  If it is determined in step S406 that transmission interruption of the optical signal has been detected (step S406: Yes), the control circuit 210 issues a warning (step S408), and the process returns to step S404.

  On the other hand, when it is determined in step S406 that transmission interruption of the optical signal is not detected (step S406: No), the control circuit 210 sets the input path to T.264. Switch to Line # 1 (step S410).

  Thereafter, the control circuit 210 performs T.P. It is determined whether or not transmission interruption of the optical signal from Line # 0 has been detected (step S412).

  If it is determined in step S412 that transmission interruption of the optical signal has not been detected (step S412: NO), the control circuit 210 sets the input path to T.264. Switching to Line # 0 (step S414), the process returns to step S404.

  On the other hand, when it is determined in step S412 that transmission interruption of the optical signal has been detected (step S412: Yes), the control circuit 210 advances the process to step S416.

  In step S416, the control circuit 210 performs T.P. It is determined whether or not transmission interruption of the optical signal from Line # 1 has been detected (step S416).

  If it is determined in step S416 that transmission interruption of the optical signal has not been detected (step S416: No), the control circuit 210 returns the process to step S412.

  On the other hand, when it is determined in step S416 that transmission interruption of the optical signal has been detected (step S416: Yes), the control circuit 210 issues a warning (step S418), and the process returns to step S412.

  According to this procedure, even after some failure occurs in the initial optical transmission line, the initial optical transmission line can be used as much as possible. This is effective when the optical transmission line is for use or when the function and performance are inferior to those of the default optical transmission line. In particular, when laying an optical transmission line, depending on whether it is aerial or underground, or whether there is a main road, railway, large-scale facility, etc., the working route (the default optical transmission line) and the detour route (other optical transmission) The length of the transmission line and the laying conditions along the way are different from those of the road), and the working route may be superior in quality and management conditions of the transmission line. In such a case, it is preferable to use the working route as much as possible. This procedure is effective in such a case.

(Another example of switching procedure)
Next, with reference to FIG. 5, another example of the procedure of the switching process of the optical switch 200 by the control circuit 210 will be described. FIG. 5 is a flowchart showing another example of the procedure of the switching process of the optical switch 200 by the control circuit 210.

  Here, when the transmission interruption of the downstream optical signal from the default optical transmission line (T.Line # 0) is detected, the input path is switched to another optical transmission line (T.Line # 1), and then Even if transmission of the downstream optical signal from the default optical transmission path is restored, the input path is not switched to the initial optical transmission path until a transmission interruption of the downstream optical signal from another optical transmission path is detected. An example will be described.

  First, the control circuit 210 sets the input path to the T.C. Switch to Line # 0 (step S502).

  Thereafter, the control circuit 210 performs T.P. It is determined whether or not transmission interruption of the optical signal from Line # 0 has been detected (step S504).

  In step S504, when it is determined that the transmission interruption of the optical signal is not detected (step S504: No), the control circuit 210 continues the determination process of step S504.

  On the other hand, if it is determined in step S504 that transmission interruption of the optical signal has been detected (step S504: Yes), the control circuit 210 advances the process to step S506.

  In step S506, the control circuit 210 performs T.P. It is determined whether or not transmission interruption of the optical signal from Line # 1 has been detected (step S506).

  If it is determined in step S506 that transmission interruption of the optical signal has been detected (step S506: Yes), the control circuit 210 issues a warning (step S508), and the process returns to step S504.

  On the other hand, if it is determined in step S506 that transmission interruption of the optical signal has not been detected (step S506: No), the control circuit 210 sets the input path to T.264. Switch to Line # 1 (step S510).

  Thereafter, the control circuit 210 performs T.P. It is determined whether or not transmission interruption of the optical signal from Line # 1 has been detected (step S512).

  If it is determined in step S512 that transmission interruption of the optical signal has not been detected (step S512: No), the control circuit 210 continues the determination process of step S512.

  On the other hand, if it is determined in step S512 that transmission interruption of the optical signal has been detected (step S512: Yes), the control circuit 210 advances the process to step S514.

  In step S514, the control circuit 210 performs T.P. It is determined whether or not transmission interruption of the optical signal from Line # 0 has been detected (step S514).

  If it is determined in step S514 that transmission interruption of the optical signal has not been detected (step S514: No), the control circuit 210 sets the input path to T.264. Switching to Line # 0 (step S516), the process returns to step S504.

  On the other hand, when it is determined in step S514 that transmission interruption of the optical signal has been detected (step S514: Yes), the control circuit 210 issues a warning (step S518), and the process returns to step S512.

  According to this procedure, after some trouble has occurred in the default transmission line and switched to another optical transmission line, it is possible to continue using the other optical transmission line as much as possible. This is effective when a highly reliable optical transmission line is desired. In particular, if there is no superiority or inferiority in the optical transmission line and no significant difference in function or performance occurs regardless of which optical transmission line is used, it is sufficient to continue to use a highly reliable optical transmission line. Switching to “1” causes a momentary disconnection and the like, leading to deterioration of the line quality and service. In such a case, operation without weighting is preferable as in this procedure. Further, according to this procedure, since the number of switching times of the optical switch can be suppressed, it is possible to avoid shortening the lifetime of the optical switch.

  In the present embodiment, T.I. Line # 0 is the default optical transmission line. Line # 1 may be the default optical transmission line. In this case, in FIGS. Line # 1 and T.W. Line # 0 will be replaced.

(effect)
As described above, the optical closure 120 according to the present embodiment is used when the optical transmission path from the center 110 is duplexed, so that some trouble occurs in one optical transmission path and the optical signal cannot be received. Even if it exists, an optical signal can be received from another optical transmission line.

  As a result, even if a failure occurs in one optical transmission line, this is detected immediately, and the optical transmission line used for transmission of the optical signal is switched to another optical transmission line. However, an optical signal received from another optical transmission line can be transmitted to each optical drop closure 130.

  In particular, the optical closure 120 of this embodiment employs a configuration that switches the input path of the optical signal when it is detected that the transmission of the optical signal from the optical transmission path is interrupted. Regardless of the content, it is possible to respond to a failure quickly and reliably with a simple configuration.

  Furthermore, the optical closure 120 of the present embodiment employs a configuration that receives the same optical signal in parallel from the two optical transmission lines. As a result, even when an optical signal cannot be received from one optical transmission path, the same optical signal can be received from the other optical transmission path. In other words, the optical closure 120 of the present embodiment can continuously transmit the transmission data that was transmitted to each optical drop closure 130 before the occurrence of the failure even after the occurrence of the failure.

[Other Embodiments]
Hereinafter, other embodiments of the optical closure 120 according to the present invention will be described. Among the optical closures 120 described in other embodiments, points other than those described below are the same as those of the optical closures 120 described so far, and thus description thereof is omitted. Hereinafter, differences from the optical closure 120 described so far will be described.

(Embodiment 2)
First, a second embodiment of the optical closure 120 according to the present invention will be described with reference to FIG. FIG. 6 is a diagram illustrating a configuration of the optical closure 120 according to the second embodiment.

(Configuration of closure)
As shown in FIG. 6, the optical closure 120 of the present embodiment does not include the optical distributor 220, that is, does not have a function of distributing and outputting the downstream optical signal to a plurality of output destinations. For this reason, one B.P. port is provided at the output side (drop closure 130 side) port of the optical switch 200. Only Line (B. Line # 0) is connected. That is, the optical closure 120 of this embodiment is configured to output a downstream optical signal to only one drop closure 130.

  The optical closure 120 of the second embodiment is the same as the optical closure 120 of the first embodiment except for the points described above. Therefore, the optical closure 120 of the second embodiment can achieve the same effects as the optical closure 120 of the first embodiment. As described above, the optical closure 120 according to the present invention can be implemented in various forms regardless of the presence / absence of an optical distributor and the number of downstream optical signal output destinations.

  In the optical transmission system 10, even when the optical closure 120 shown in FIG. 6 is used, an optical distributor shown in FIG. As in the case of using 120 (Embodiment 1), the downstream optical signal can be distributed to a plurality of output destinations and output.

(Embodiment 3)
Next, a third embodiment of the optical closure 120 according to the present invention will be described with reference to FIG. FIG. 7 is a diagram illustrating a configuration of the optical closure 120 according to the third embodiment.

(Configuration of closure)
From the center 110 to the optical closure 120, T.I. Line # 0 and T.W. In addition to the optical signals for various transmission data, a monitoring optical signal that is an optical signal having a predetermined wavelength (for example, 1620 nm to 1660 nm) is transmitted from each of Line # 1. This optical signal for monitoring has a wavelength different from that of at least an optical signal for various transmission data, and is continuously transmitted at a relatively short interval. The monitoring optical signal may be CW (Continuous Wave) light (that is, continuous light), but it is desirable to use modulated light from the viewpoint of power saving.

  Accordingly, the optical closure 120 of this embodiment further includes optical wavelength filters 262, 264, and 266 that transmit optical signals for monitoring, as shown in FIG.

  The optical wavelength filter 262 transmits and outputs a monitoring optical signal having a predetermined wavelength from the optical signal supplied from the optical coupler 242. The monitoring optical signal output from the optical wavelength filter 262 is output to the detection circuit 252. Based on the supply of the optical signal for monitoring from the optical wavelength filter 262, the detection circuit 252 receives the T.P. The transmission interruption of the monitoring optical signal from Line # 0 is detected. For example, when a monitoring optical signal is not supplied from the optical wavelength filter 262 for a predetermined time or more, the detection circuit 252 detects this as a transmission interruption of the monitoring optical signal. When detecting the transmission interruption, the detection circuit 252 notifies the control circuit 210 accordingly.

  In response to the notification of the interruption of the supply of the downstream optical signal, for example, the control circuit 210 causes the T.P. Line # 0 or T. In the transmission system of the optical signal to Line # 0, it can be detected that some kind of failure has occurred.

  The optical wavelength filter 264 transmits and outputs a monitoring optical signal from the optical signal supplied from the optical coupler 244. The monitoring optical signal output from the optical wavelength filter 264 is output to the detection circuit 254. Based on the supply of the optical signal for monitoring from the optical wavelength filter 264, the detection circuit 254 receives the T.P. The transmission interruption of the optical signal for monitoring from Line # 1 is detected. For example, if the optical signal for monitoring has not been supplied from the optical wavelength filter 264 for a predetermined time or longer, the detection circuit 254 determines that the T.D. This is detected as a transmission interruption of the monitoring optical signal from Line # 1. When detecting the transmission interruption, the detection circuit 254 notifies the control circuit 210 to that effect.

  With this notification, the control circuit 210, for example, Line # 1 or T. In the transmission system of the optical signal to Line # 1, it can be detected that some kind of failure has occurred.

  The optical wavelength filter 266 transmits and outputs a monitoring optical signal from the optical signal supplied from the optical coupler 246. The monitoring optical signal output from the optical wavelength filter 266 is output to the detection circuit 256. The detection circuit 256 detects transmission interruption of the monitoring optical signal from the optical switch 200 based on the supply of the monitoring optical signal from the optical wavelength filter 266. For example, when the monitoring optical signal is not supplied from the optical wavelength filter 266 for a predetermined time or more, the detection circuit 256 detects this as a transmission interruption of the monitoring optical signal from the optical switch 200. . When detecting the transmission interruption, the detection circuit 256 notifies the control circuit 210 to that effect.

  By this notification, for example, the control circuit 210 can detect that some failure has occurred in the optical switch 200.

  As described above, according to the optical closure 120 of the third embodiment, some failure occurred in each optical transmission line and the optical switch 200 by detecting the transmission interruption of the monitoring optical signal transmitted continuously. Can be detected.

  For this reason, even in the case where an optical signal for transmission data is not continuously transmitted, such as a burst line (for example, GE-PON) that transmits a large amount of data collectively at a certain interval, It is possible to detect that some kind of failure has occurred in the optical transmission line and the optical switch 200.

(Embodiment 4)
Next, a fourth embodiment of the optical closure 120 according to the present invention will be described with reference to FIG. Particularly, in the fourth embodiment, a modified example of the configuration for detecting both the upstream signal and the downstream signal will be described. FIG. 8 is a diagram illustrating a configuration of the optical closure 120 according to the fourth embodiment.

(Configuration for detecting transmission interruption of optical signal of T. Line # 0)
The optical closure 120 according to the fourth embodiment is a T.D. An optical coupler 802, a detection circuit 804, and a detection circuit 806 are provided as a configuration for detecting transmission interruption of the optical signal of Line # 0.

  The optical coupler 802 (optical coupler # 0) A function of branching an upstream signal to Line # 0 and outputting it to the detection circuit 804 (detection circuit # 0a); Each has a function of branching a downstream signal from Line # 0 and outputting it to the detection circuit 806 (detection circuit # 0b).

  Based on the supply of the optical signal from the optical coupler 802, the detection circuit 804 detects the T.P. A transmission interruption of the upstream optical signal to Line # 0 is detected.

  Based on the supply of the optical signal from the optical coupler 802, the detection circuit 806 detects the T.P. A transmission interruption of the downstream optical signal from Line # 0 is detected.

  For example, when no optical signal is supplied from the optical coupler 802 for a predetermined time or more, the detection circuits 804 and 806 detect this as a transmission interruption of the optical signal.

(Configuration for detecting transmission interruption of optical signal of T. Line # 1)
In addition, the optical closure 120 of the fourth embodiment is a T.D. An optical coupler 812, a detection circuit 814, and a detection circuit 816 are provided as a configuration for detecting transmission interruption of the optical signal of Line # 1.

  The optical coupler 812 (optical coupler # 1) A function of branching an upstream signal to Line # 1 and outputting it to the detection circuit 814 (detection circuit # 1a); Each has a function of branching a downstream signal from Line # 1 and outputting it to the detection circuit 816 (detection circuit # 1b).

  Based on the supply of the optical signal from the optical coupler 812, the detection circuit 814 detects the T.P. A transmission interruption of the upstream optical signal to Line # 1 is detected.

  Based on the supply of the optical signal from the optical coupler 812, the detection circuit 816 detects the T.P. A transmission interruption of the downstream optical signal from Line # 1 is detected.

  For example, when no optical signal is supplied from the optical coupler 812 for a predetermined time or more, the detection circuits 814 and 816 detect this as a transmission interruption of the optical signal.

  As described above, the optical closure 120 of the fourth embodiment employs the optical couplers 802 and 812 that can branch the upstream optical signal and the downstream optical signal. Accordingly, it is possible to reduce the number of installed optical couplers while making it possible to detect that some kind of failure has occurred in the optical switch, thereby reducing the insertion loss of the optical coupler and the manufacturing cost of the entire system.

(Embodiment 5)
Next, with reference to FIG. 9, Embodiment 5 of the optical closure 120 which concerns on this invention is demonstrated. In particular, in the fifth embodiment, a modified example of a configuration that generates power using light from the outside will be described. FIG. 9 is a diagram illustrating a configuration of the optical closure 120 according to the fifth embodiment.

  The optical closure 120 of the fifth embodiment includes a power supply generation circuit 900. The power generation circuit 900 is an optical transmission line for transmitting light for generating power. It is connected to the center 110 by Line. This P.I. For example, an optical fiber not used for communication (so-called dark fiber) wired in an optical cable together with an optical fiber used for communication is used for Line. The center 110 is connected to the P.C. Light for power generation is transmitted to the power generation circuit 900 via the Line.

  For example, the center 110 generates power as light for generating power using light (0.98 μm, etc.) emitted from an excitation light source used for an optical amplifier, light emitted from a YAG laser (1.06 μm), etc. Transmit to circuit 900. As the power generation light, various types of modulated light may be used, but CW light is preferably used in order to efficiently supply power.

  The power supply generation circuit 900 is the same as the P.C. The power generation light transmitted from the line is received, the power is generated by performing photoelectric conversion using the power generation light, and a predetermined voltage for operating the optical closure 120 is output.

  For example, the power supply generation circuit 900 includes a P.D. The power generation light transmitted from the line is received, and a certain amount of voltage (for example, 0.6 V) is generated. Then, the voltage of the electric power generated by the photodiode is boosted to a predetermined voltage (for example, 3.3 V) by a boosting DC / DC converter. Accordingly, the power generation circuit 900 can obtain a predetermined voltage for operating the optical closure 120. The optical closure 120 (especially the control circuit 200) can be operated by the power generated by the power generation circuit 900.

  The electric power generated by the power generation circuit 900 can be stored in the storage battery 234. As a result, when the power generation amount by the power generation circuit 900 is sufficient, the optical closure 120 operates with the power generated by the power generation circuit 900, charges the storage battery 234, and generates the power generation amount by the power generation circuit 900. In the case where it is insufficient, it can be operated by the electric power stored in the storage battery 234.

  According to the configuration of the fifth embodiment, since it is not necessary to provide a power supply power line, the configuration of the optical transmission system 10 can be simplified.

  Further, when the transmission distance is long, the energy loss is smaller when the power is converted into light and transmitted by the optical fiber than when the power is transmitted as it is by the power line. In such a case, according to the configuration of the fifth embodiment, energy loss can be further reduced.

  In the fifth embodiment, power generation light is transmitted from the center 110. However, power generation light may be transmitted from other devices. Alternatively, a plurality of optical transmission lines (P. Line) for generating power may be provided, and light for generating power may be transmitted to the power generation circuit 900 from each of the plurality of optical transmission paths.

(Embodiment 6)
Next, a sixth embodiment of the optical closure 120 according to the present invention will be described with reference to FIG. In particular, in the sixth embodiment, a further modification of the configuration for generating power using light from the outside will be described. FIG. 10 is a diagram illustrating a configuration of the optical closure 120 according to the sixth embodiment.

  In the sixth embodiment, the center 110 is the T.30. Light for power generation is transmitted to the power generation circuit 1012 via Line # 0. Further, the center 110 is connected to the T.W. Light for power generation is transmitted to the power generation circuit 1014 via Line # 1.

  For example, the center 110 generates power as light for generating power using light (0.98 μm, etc.) emitted from an excitation light source used for an optical amplifier, light emitted from a YAG laser (1.06 μm), etc. Transmit to circuits 1012 and 1014. As the power generation light, various types of modulated light may be used, but CW light is preferably used in order to efficiently supply power.

  The power supply generation circuits 1012 and 1014 are connected to the T.W. The power generation light transmitted from the Lines # 0 and # 1 is received, and the power generation is performed by performing photoelectric conversion using the power generation light, and a predetermined voltage for operating the optical closure 120 is obtained. Output.

  Specifically, the optical closure 120 of the sixth embodiment includes an optical coupler 1002, a power supply generation circuit 1012, an optical coupler 1004, and a power supply generation circuit 1014.

  The optical coupler 1002 (optical coupler # 0a) It is provided on the path of Line # 0. The optical coupler 1002 is a T.W. The downstream optical signal transmitted from Line # 0 is distributed to the power generation circuit 1012 (power generation circuit # 0). The power generation circuit 1012 receives the downstream optical signal supplied from the optical coupler 1002, generates power by performing photoelectric conversion using this light, and outputs a predetermined voltage for operating the optical closure 120.

  The optical coupler 1004 (optical coupler # 1a) It is provided on the path of Line # 1. The optical coupler 1004 is a T.W. The downstream optical signal transmitted from Line # 1 is distributed to the power generation circuit 1014 (power generation circuit # 1). The power generation circuit 1014 receives the downstream optical signal supplied from the optical coupler 1004, generates power by performing photoelectric conversion using this light, and outputs a predetermined voltage for operating the optical closure 120.

  The mechanism for the power generation circuits 1012 and 1014 to output a predetermined voltage is the same as that of the power generation circuit 900. The optical closure 120 (particularly the control circuit 200) can be operated by the power generated by the power generation circuits 1012 and 1014.

  The electric power generated by the power generation circuits 1012 and 1014 can be stored in the storage battery 234. Accordingly, when the power generation amount by the power generation circuits 1012 and 1014 is sufficient, the optical closure 120 operates with the power generated by the power generation circuits 1012 and 1014, charges the storage battery 234, and supplies the power generation circuit 1012. , 1014 can be operated by the electric power stored in the storage battery 234.

  According to the configuration of the sixth embodiment, it is not necessary to provide a power line for supplying power, and it is not necessary to provide an optical transmission line (P. Line) for transmitting power generation light. The configuration of the system 10 can be further simplified.

  Also, the optical signal transmitted from the optical transmission line not selected by the optical switch is used for generating power without being discarded, so that the optical energy can be used effectively.

  Note that the power generation circuits 1012 and 1014 can generate power not only from an optical signal for power generation but also from an optical signal for transmission data.

  For this reason, if the power generated from the optical signal for transmission data is sufficient for the optical closure 120 to operate, the center 110 may not transmit the optical signal for power generation.

  Further, the configuration of the sixth embodiment may be modified so that power is generated using only the optical signal transmitted from the optical transmission path not selected by the optical switch. As a result, transmission data transmitted from the optical transmission path selected by the optical switch can be transmitted without loss, and power can be generated in parallel with this.

[Modification]
In each embodiment, the example using an optical coupler and an optical wavelength filter has been described as an example of an extraction unit that extracts an optical signal for transmission interruption detection and an optical signal for power generation. The extraction means is not limited to the optical coupler and the optical wavelength filter, and any other configuration may be used as long as it can extract at least an optical signal for transmission interruption detection or an optical signal for power generation. . For example, a WDM (Wavelength Division Multiplexing) filter (long pass filter, short pass filter, or band pass filter) may be used as the extraction means. A WDM filter transmits an optical signal in a certain wavelength band out of an optical signal incident from a common port and outputs it from a transmission port, while reflecting an optical signal in another wavelength band and outputting it from a reflection port. It is something that can be done. Utilizing this characteristic, a transmission data optical signal is transmitted and output from a transmission port, while a transmission interruption detection optical signal or a power generation optical signal is reflected and output from a reflection port. By designing this, the WDM filter can function as the extraction means. Hereinafter, as a modification of the third and sixth embodiments, an example in which a WDM filter is used as the extraction unit will be described.

(Modification 1: Modification of Embodiment 3)
First, with reference to FIG. 11, the modification of the optical closure 120 (FIG. 7) of Embodiment 3 is demonstrated. FIG. 11 is a diagram illustrating a modification of the optical closure 120 according to the third embodiment.

  The optical closure 120 shown in FIG. 11 uses a WDM filter 1102 instead of the optical coupler 242 and the optical wavelength filter 262 as the extraction means, and a WDM filter 1104 instead of the optical coupler 244 and the optical wavelength filter 264. Is different from the optical closure 120 shown in FIG. Further, in the optical closure 120 shown in FIG. 11, the optical coupler 246, the optical wavelength filter 266, and the detection circuit 256 shown in FIG.

  In particular, the WDM filters 1102 and 1104 shown in FIG. 11 have the wavelength of the optical signal for transmission data (downward: 1480 nm to 1580 nm, upstream: 1260 nm to 1360 nm) and the wavelength of the optical signal for detection of transmission interruption (1620 nm to 1660 nm). Accordingly, an optical signal having a wavelength shorter than 1.6 μm (1600 nm) is transmitted and output from the transmission port, while an optical signal having a wavelength longer than 1.6 μm (1600 nm) is reflected and output from the reflection port. Designed to function as a short pass filter.

  That is, the WDM filters 1102 and 1104 have a threshold value for separating transmission and reflection so that the transmission data optical signal and the power generation optical signal are output from different ports. It is set in the middle between the wavelength and the wavelength of the optical signal for detecting transmission interruption.

  As a result, the WDM filters 1102 and 1104 shown in FIG. 11 transmit optical signals for transmission data (downward: 1480 nm to 1580 nm, upstream: 1260 nm to 1360 nm) and output from the transmission port, while transmitting light for detecting transmission interruptions. The signal (1620 nm to 1660 nm) can be reflected and output from the reflection port.

  According to this modification, by using a WDM filter as the extraction means, it is possible to suppress an insertion loss of an optical signal for transmission interruption while suppressing an insertion loss of an optical signal for transmission data. Since all the optical signals for detecting transmission interruption are output from the reflection ports by the WDM filters 1102 and 1104, the optical coupler 246, the optical wavelength filter 266, and the detection circuit 256 shown in FIG. ing.

(Modification 2: Modification of Embodiment 6)
Next, a modification of the optical closure 120 (FIG. 10) of the sixth embodiment will be described with reference to FIG. FIG. 12 is a diagram illustrating a modification of the optical closure 120 according to the sixth embodiment.

  The optical closure 120 shown in FIG. 12 uses the WDM filter 1202 instead of the optical coupler 1002 as the extraction means and the WDM filter 1204 instead of the optical coupler 1004. Different from the optical closure 120 shown in FIG.

  In particular, the WDM filters 1202 and 1204 shown in FIG. 12 have wavelengths of optical signals for transmission data (downward: 1480 nm to 1580 nm, upstream: 1260 nm to 1360 nm) and wavelengths of optical signals for power generation (0.98 μm,. The optical signal having a wavelength longer than 1.2 μm (1200 nm) is transmitted and output from the transmission port, while the optical signal having a wavelength shorter than 1.2 μm (1200 nm) is reflected and reflected from the reflection port. It is designed to function as a long pass filter that outputs.

  That is, the WDM filters 1202 and 1204 have a threshold value that separates transmission and reflection so that the optical signal for transmission data and the optical signal for power generation are output from different ports. It is set in the middle between the wavelength and the wavelength of the optical signal for power generation.

  Accordingly, the WDM filters 1202 and 1204 shown in FIG. 12 transmit the optical signal for transmission data (downward: 1480 nm to 1580 nm, upstream: 1260 nm to 1360 nm) and output from the transmission port, while the optical signal for generating power (0.98 μm, 1.06 μm) can be reflected and output from the reflection port.

  According to this modification, by using the WDM filter as the extraction means, it is possible to suppress the insertion loss of the optical signal for generating power while suppressing the insertion loss of the optical signal for transmission data.

(Supplementary explanation)
The embodiments according to the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  For example, in order to obtain more sufficient power for the optical closure 120 to operate, a configuration that generates power using sunlight (any one of the first to fourth embodiments) and power generation transmitted from the center 110 are generated. A configuration in which power is generated using an optical signal for transmission or an optical signal for transmission data (Embodiment 5 or 6) may be implemented in combination.

  The optical transmission system according to the present invention can be suitably used as an access network, in particular, an access network for a system in which service provision is not permitted to be interrupted, such as an Internet line or a CATV system.

10 Optical transmission system 110 Center 120 Optical closure (optical repeater)
130 optical drop closure 200 optical switch 210 control circuit 220 optical distributor 232 photovoltaic power generation panel (photoelectric conversion means)
234 Storage battery 242 Optical coupler 244 Optical coupler 246 Optical coupler 252 Detection circuit (detection means)
254 detection circuit (detection means)
256 detection circuit 900 power generation circuit (photoelectric conversion means)

Claims (9)

An optical repeater that is connected to two or more optical transmission lines that transmit an optical signal transmitted from the center and relays the optical signal transmitted through one of the two or more optical transmission lines; An optical transmission system comprising:
The optical repeater is configured to detect whether an optical signal is normally transmitted through at least the first optical transmission line, and to transmit the optical signal normally via the first optical transmission line. An optical switch that switches the optical transmission path to be relayed from the first optical transmission path to the second optical transmission path when the detection means detects that the detection is not performed,
An optical transmission system characterized by that. The optical signals transmitted from the center and transmitted through the two or more optical transmission lines are the same optical signal.
The optical transmission system according to claim 1. The optical signal transmitted from the center and transmitted through the two or more optical transmission lines includes monitoring signal light having a specific wavelength,
The detecting means detects whether or not the monitoring signal light is normally transmitted through the first optical transmission line;
The optical transmission system according to claim 1 or 2. The optical switch switches an optical transmission line to be relayed from the first optical transmission line to the second optical transmission line, and then an optical signal is normally transmitted through the first optical transmission line. When the detection means detects that the optical transmission line is to be relayed, the optical transmission line to be relayed is switched from the second optical transmission line to the first optical transmission line.
The optical transmission system according to claim 1, wherein the optical transmission system is an optical transmission system. Whether the optical signal is normally transmitted through the second optical transmission line in addition to whether the optical signal is normally transmitted through the first optical transmission line Is to detect,
The optical switch switches an optical transmission line to be relayed from the first optical transmission line to the second optical transmission line, and then an optical signal is normally transmitted through the second optical transmission line. Detecting that the optical transmission line is to be relayed, the second optical transmission line is switched to the first optical transmission line.
The optical transmission system according to claim 1, wherein the optical transmission system is an optical transmission system. The optical repeater further includes a photoelectric conversion unit, and operates with electric power generated by the photoelectric conversion unit.
The optical transmission system according to any one of claims 1 to 5, wherein: The photoelectric conversion means generates electric power from signal light transmitted via any one of the two or more optical transmission paths.
The optical transmission system according to claim 6. The photoelectric conversion means generates electric power from sunlight.
The optical transmission system according to claim 6. An optical repeater that is connected to two or more optical transmission lines that transmit an optical signal transmitted from a center and relays an optical signal transmitted through one of the two or more optical transmission lines,
Detecting means for detecting whether or not the optical signal is normally transmitted through the first optical transmission line;
When the detecting means detects that the optical signal is not normally transmitted through the first optical transmission line, the optical transmission line to be relayed is changed from the first optical transmission line to the second optical transmission line. An optical switch for switching to a transmission line,
An optical repeater characterized by that.

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