JPH06197082A - Optical network - Google Patents

Abstract

PURPOSE:To make the size of a patch panel and a node small by using only one optical fiber led from each node so as to reduce the total extension of the length of the optical fiber in use, decreasing number of optical connectors and reducing the space occupied by the connector in components. CONSTITUTION:Optical circulators 70, 71 are respectively provided to a patch panel 22 and nodes 13-16. A signal light outputted from an optical transmitter 43 of the node 13 is sent to the patch panel 22 via a transmission reception common use optical fiber 35 by the circulator 71. The signal light sent from the patch panel 22 is sent to the adjacent node 14 via the optical fiber 35 by the circulator 70. The signal light sent from the adjacent node 15 via the patch panel 22 and the transmission reception common use optical fiber 35 is sent to an optical receiver 44 by the optical circulator 71 in the node 13. Thus, the two-way signal is sent through one optical fiber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical network in which only one fiber is drawn from a node of the network.

[0002]

2. Description of the Related Art Generally, when constructing an optical loop network, an optical fiber and each network constituent device are connected as shown in FIG. The network node 10 is connected to the input / output port 50 of the patch panel 20. At this time, the optical fiber 1 drawn from the optical transmitter 41 of the node 10 is used as the receiving optical connector 51 of the patch panel 20, and the optical fiber 2 drawn from the optical receiver 42 is used as the transmitting optical fiber of the patch panel 20. Connect to the connector 52. The inside of the patch panel 20 is the transmission optical fiber 1 of the node 10.
The signal light output from the node 11 is sent to the receiving optical fiber 3 of the adjacent node 11 and is received by the receiving optical fiber 2 of the node 10.
It is wired so as to send the transmission light from the adjacent node 12 on the opposite side. The connections within the patch panel 20 are made by optical fibers. In the network shown in FIG. 4, each node 10 to 13 has the same configuration. An unused port adapter 61 is connected to an unused port of the input / output ports 50 of the patch panel 20 to return the signal light. With the above connections, the network is configured in a loop by each node and the optical fiber. By connecting the patch panel 20 to another patch panel 21 with the optical fiber 4, the number of nodes can be expanded.

An optical loop network can be easily constructed by using the above-mentioned connection method using the patch panel 20. This is because the optical fiber drawn from each node of the network need only be connected to the patch panel and need not be directly connected to the other two nodes, which facilitates the wiring of the optical fiber. With such a configuration, it is easy to install or abolish a node. Further, if a plurality of patch panels are connected by optical fibers, the number of nodes that can be connected to the network can be arbitrarily increased.

[0004]

However, in the above-mentioned conventional technique, when connecting each node of the network and the patch panel, it is necessary to connect two optical fibers for transmission and reception.

For this reason, not only the total length of the optical fiber used becomes long, but also a large number of highly accurate optical connectors must be used. In addition, since the space occupied by the connectors in the network constituent device is large, there is a drawback that the patch panel and the node become large.

An object of the present invention is to provide an optical network in which the above-mentioned drawbacks of the prior art are eliminated and the fiber length is short, the number of optical connectors is small, and the size can be reduced by unifying one optical fiber from a node. To do.

[0007]

According to the optical network of the present invention, in an optical loop network in which optical fibers drawn from each node are gathered in a concentrator and the nodes are network-connected, the optical fibers drawn from each node are shared for transmission and reception. A single circulator is provided in the concentrating unit, which transmits the signal light transmitted from each node through the optical fiber for both transmission and reception to the adjacent node through the optical fiber for both transmission and reception. A second optical signal that is transmitted from the optical transmitter in the node is transmitted through the shared optical fiber for transmission and reception, and the optical signal transmitted through the optical fiber is transmitted to the optical receiver in the node. An optical circulator is provided.

The optical network of the present invention is an optical loop network in which optical fibers drawn from each node are gathered in a concentrator to connect the nodes to each other by a network.
The optical fibers drawn from each node are shared for both transmission and reception, and integrated, and the signal light transmitted from each node via the transmission / reception shared optical fiber to the concentrator is transmitted to the adjacent node via the transmission / reception shared optical fiber. A circulator is provided, and at each node, the signal light output from the optical transmitter in the node is coupled to the transmission / reception shared optical fiber, and the signal light transmitted through this optical fiber is branched to An optical coupler for transmitting to an optical receiver is provided.

Further, the optical network of the present invention is an optical loop network in which optical fibers drawn from each node are gathered in a concentrator and the nodes are connected to each other by a network.
The optical fibers drawn from each node are shared for both transmission and reception, and integrated, and the signal light transmitted from each node via the transmission / reception shared optical fiber to the concentrator is transmitted to the adjacent node via the transmission / reception shared optical fiber. A circulator is provided, and when the signal light is output from the optical transmitter in the node to each node, the shared optical fiber for transmission and reception is switched and connected to the optical transmitter, and when the signal light is transmitted through this optical fiber, the optical signal is transmitted. An optical switch is provided to switch and connect the fiber to the optical receiver in the same node.

The optical network has a loop structure, a bus structure, a star structure, and a combination of these structures.

[0011]

When the signal light is transmitted from a certain node, the signal light output from the optical transmitter of the node is transmitted to the concentrator by the second circulator via the optical fiber for both transmission and reception connected to the node. . The signal light transmitted to the concentrator is transmitted by the first circulator to only the node adjacent to the node through the optical fiber for both transmission and reception.

When receiving a signal light from another node,
The signal light transmitted from the adjacent node via the optical fiber for both transmission and reception is transmitted only to the optical receiver by the second circulator in the node.

By thus providing the optical circulator in the concentrator, bidirectional signals can be transmitted through one optical fiber, and only one optical fiber connecting the node and the concentrator is required. Therefore, it is possible to reduce the number of optical fibers and optical connectors required for the network, which also contributes to downsizing of the devices constituting the system.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a first optical circulator 70 is installed in the patch panel 22 which constitutes the concentrator, and four ports A, B, C, of the optical circulator 70 are installed.
D is connected to four optical signal input / output ports 53 for connecting the nodes 13 to 16, respectively. The optical circulator 70 outputs the light incident from the port A to the port B, the light incident from the port B to the port C, the light incident from the port C to the port D, and the light incident from the port D to the port A. There is. Each of the input / output ports 53 is
Unlike the conventional technology, it is not divided into transmitting and receiving,
It is used for both transmission and reception. The patch panel 22 and the nodes 13 to 16 are connected to each other through the input / output port 53 by one transmission / reception shared optical fiber 35 to 38.

Here, the configuration in each of the nodes 13 to 16 is the same. Explaining with the node 13 showing the configuration as a representative, the optical transmitter 43 for transmitting the transmission signal light, the optical receiver 44 for receiving the reception signal light, the drawn out transmission / reception shared optical fiber 35, and the second An optical circulator 71 is installed. The three ports E, F, G of the second optical circulator 71 are connected to the optical transmitter 43, the transmission / reception shared optical fiber 35, and the optical receiver 44, respectively. The optical circulator 71 transmits the light incident from the port E to the port F,
It has a function of outputting the light incident from the port F to the port G.

The transmission signal light output from the optical transmitter 43 of the node 13 enters the patch panel 22 through the optical circulator 71 in the node 13, the transmission / reception shared optical fiber 35, and the transmission / reception shared optical connector 54, and the inside of the patch panel 22. Is sent to the adjacent node 14 through the optical circulator 70 of FIG. This adjacent node 1
The signal light sent to the optical fiber 4 is sent to the optical receiver by the optical circulator in the node 14. On the other hand, node 1
The signal light input to 3 is transmitted from the optical transmitter of the adjacent node 15 on the opposite side to the optical circulator, the transmission / reception optical fiber 37,
The light is input to the optical receiver 44 through the optical circulator 70, the transmission / reception optical fiber 35, and the optical circulator 71.

As described above, by providing the optical circulator 70 in the patch panel 22, it is possible to distribute the light propagating in the optical fiber in different traveling directions to different optical fibers. Therefore, between the patch panel and the node. The optical fiber can be used for both transmission and reception. This works regardless of the fact that the signal light wavelengths of transmission and reception of the nodes are the same. Further, since the optical circulator can be made polarization independent, it is not affected by the polarization of the network signal light.

With the above configuration, the number of optical fibers connecting each node of the loop network and the patch panel does not need to be two for transmission and one for reception, and only one is required. That is, an optical loop network can be constructed with a single fiber. This is extremely effective especially in places where the fiber core is restricted. It is not necessary to separately provide a connector for connecting an optical fiber for transmitting and for receiving. Therefore, the amount of optical fibers and optical connectors required for constructing a network system can be reduced to about half that of the conventional technology. Since the number of optical connectors can be reduced, it is possible to downsize the devices that make up the network. Also, the connection work when installing or changing the network is reduced. Further, the degree of freedom for expanding the network system such as adding the number of nodes is large as in the prior art shown in FIG.

FIG. 2 shows a modification of the internal structure of the node 13. An optical coupler 80 is used instead of the optical circulator. The output light of the optical transmitter 43 does not proceed in the direction of the optical receiver 44 and is all output to the optical fiber 35. Unlike the case where the optical circulator is used, the light input to the node 13 from the optical fiber 35 is sent not only to the optical receiver 44 but also to the optical transmitter 43. The optical transmitter 43 does not cause any particular problem in operation even if signal light is input, but since the signal light sent to the optical receiver 44 decreases by about 3 dB, the reception sensitivity deteriorates. However, the optical coupler 80 has a much simpler structure than the optical circulator and is inexpensive. For this reason,
Even if the receiving sensitivity is somewhat deteriorated, the advantage of using the optical coupler is great.

FIG. 3 shows another embodiment of the present invention, which is an extension of the network configuration shown in FIG. The patch panel 23 is connected to the patch panel 22 by an optical fiber 38. Furthermore, the optical fiber 39 which came out from the patch panel 23 is connected to another patch panel. An unused port adapter 62 that totally reflects light is connected to an unused port 56 of the input / output ports 55 of the patch panel 23. As described above, the network to which the present invention is applied can be freely expanded, and in this respect, it is not inferior to the prior art. As the network is expanded, the total length of the optical fiber and the number of optical connectors are increased, so that the effect of reducing them is increased by the present invention. It should be noted that the patch panel is not limited to only four ports, but the number of ports can be increased by increasing the number of built-in optical circulators.

In the above embodiments, the case where the signal switching in the node is performed by the circulator or the optical coupler has been described. Instead of these, when the signal light is output from the optical transmitter in the node, the common optical fiber for transmission and reception is used. Alternatively, an optical switch may be connected to the optical transmitter so as to switch the optical fiber to the optical receiver in the node when the signal light is transmitted through the optical fiber. In this case, the switching signal of the optical switch is required, but it may be sent from the optical transmitter at the time of transmission and appropriately sent at the time of reception.

[0023]

(1) According to claim 1, it is possible to realize an optical network in which the number of optical fibers connecting a node and a concentrator is one. Therefore, the total extension of the optical fiber and the number of optical connectors can be reduced to about half of the conventional one. In addition, since the number of connectors is reduced, it is possible to miniaturize the devices that make up the network. Further, the work involved in installing and changing the network can be reduced.

(2) According to the second aspect, since the second optical circulator is an optical coupler, the receiving sensitivity is somewhat lowered, but the structure is simple and the cost can be reduced as compared with the optical circulator.

(3) According to the third aspect, since the third optical circulator is an optical switch, a switching signal is required, but the structure is simple and inexpensive compared to the optical circulator.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an optical network of the present invention.

FIG. 2 shows a modification of the configuration of the node of the present embodiment.

FIG. 3 is a configuration diagram showing another embodiment in which the network of the present invention is expanded.

FIG. 4 is a configuration diagram of a conventional general optical loop network.

[Explanation of symbols]

 10 to 16 nodes 20 to 23 Patch panel 31 to 39 Transmission / reception shared optical fiber 43 Optical transmitter 44 Optical receiver 54, 56 Transmission / reception shared connector 62 Unused port adapter 70 First optical circulator 71 Second optical circulator 80 Optical Coupler

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location H04L 12/44 8838-5K H04L 11/00 330 8732-5K 340

Claims (3)

[Claims] 1. In an optical network in which optical fibers drawn from each node are gathered in a concentrator to connect the nodes to a network, the optical fibers drawn from each node are shared for transmission and reception, and the concentrator is connected to each node from each node. A first optical circulator that transmits the signal light transmitted through the optical fiber for both transmission and reception to the adjacent node through the optical fiber for both transmission and reception is provided, and each node outputs it from the optical transmitter in the node. And a second optical circulator for transmitting the signal light transmitted through the optical fiber for both transmission and reception, and transmitting the signal light transmitted through the optical fiber to the optical receiver in the node. Optical network to do. 2. The optical network according to claim 1, wherein instead of the second optical circulator provided in each node, a signal light output from an optical transmitter in the node is coupled to a shared optical fiber for transmission and reception. An optical network including an optical coupler for branching signal light transmitted through the optical fiber and outputting the branched signal light to an optical receiver in the node. 3. The optical network according to claim 1, wherein instead of the second optical circulator provided in each of the nodes, an optical transmission / reception shared optical fiber is optically transmitted when a signal light is output from an optical transmitter in the node. And an optical switch for switching and connecting the optical fiber to an optical receiver in the node when signal light is transmitted through the optical fiber.