JPH0648820B2 - Optical data transmission device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical data transmission device used in an optical loop network system, and more particularly to a module for transmitting / receiving an optical signal to / from a transmission line in the optical data transmission device ( Hereinafter, it will be referred to as an optical transceiver module).

[Background of the Invention]

FIG. 2 shows an example of the optical loop network system.
In this figure, 104 and 105 are transmission lines using optical fibers, respectively.
The transmission line 105 is used as a backup transmission line. 101, 102,
Reference numerals 103 are optical data transmission devices (respectively referred to as nodes A, B, and C), which are connected in series in a loop by transmission lines 104 and 105 to form an optical loop network system. During normal system operation, data flows as indicated by arrows in the figure.

FIG. 3 shows a schematic configuration of such a conventional optical data transmission device. In this figure, 203 and 206 are optical receiving modules that receive optical signals from the working transmission path 104 and the standby transmission path 105, respectively. Each of the optical receiving modules 203 and 206 includes an optical connection portion with a transmission line, a photoelectric conversion portion that converts an optical signal into an electric signal, and a circuit that extracts a clock from the received signal.
Reference numerals 204 and 205 denote optical transmission modules for transmitting optical signals to the active transmission path 104 and the standby transmission path 105, respectively. The optical transmission modules 204 and 205 are composed of an optical coupling section with a transmission line, an electro-optical conversion section for converting an electric signal into an optical signal, and the like.

The specific configuration of such an optical transceiver module is
For example, PP. Of “Hitachi Kenron” (October 1983 Vol. 65). 61-66, further description is omitted.

In the conventional optical data transmission apparatus, as shown in the figure, the optical receiving module 203 and the optical transmitting module 20 of the active system are used.
4 is mounted on a common circuit board (optical board) 201, and the standby optical transmission module 205 and the optical receiving module 206 are mounted on a common circuit board (optical board) 202. Each of the optical boards 201 and 202 is also equipped with circuits involved in error checking of received data, detection of received optical signals, transmission timing control of optical signals, and an interface with the basic unit 207 of the apparatus. The basic unit 207 is a unit that is involved in a loopback function described later, processing of transmitted / received data, and an interface with the outside of the device.

Now, in such an optical loop network system,
The loopback function is used when adding optical data transmission equipment. The loopback function is known from JP-A-57-173245.

For example, when an optical data transmission device is added between the node B and the node C, in the optical data transmission device 102 of the node B, the optical receiving module 203 is switched from the working transmission line 104.
The data received by the optical transmission module 205 is transmitted to the standby system transmission line 105 via the basic unit 207. On the other hand, in the optical data transmission device 103 of the node C, the data received by the optical reception module 206 from the standby transmission line 105 is transmitted to the active transmission line 104 by the optical transmission module 204 via the basic unit 207. By such a loopback, the system is reconfigured into the form shown in FIG. 4, and the data flows as shown by the arrow in the figure.

In such a loopback state, the optical transmission / reception modules 205, 206 of the optical data transmission device 102 of the node B and the optical transmission / reception modules 204, 203 of the optical data transmission device 103 of the node C are used as an extension optical data transmission device in the active system. By connecting the transmission line and the backup transmission line, the expansion is completed, and when the loopback state is returned to the normal state, normal system operation is possible. The state is shown in FIG. In this figure, reference numeral 501 denotes an increased optical data transmission device (node D), and 502 and 503 are transmission lines of an active system and a standby system for expansion, respectively.

However, there are cases in which it is not possible to expand in such a system operating state. For example, while nodes A, B, and C perform short wavelength transmission (generally referred to as transmission in the 0.8 to 0.9 μm band) to each other at a relatively short distance, the node D to be added is at a long distance. , Long-wavelength transmission (generally, the transmission frequency band is 1.3 μm band) is performed between the nodes B and C.

In this case, it is necessary to replace the optical transmission / reception modules 204 and 206 in the optical data transmission device 102 of the node B with those for long wavelength transmission. At the same time, it is necessary to replace the optical transmission / reception modules 205 and 203 in the optical data transmission device 103 of the node C with those for long wavelength transmission. However, in the conventional optical data transmission device, the optical transmission / reception module is mounted as shown in FIG. 3, and both nodes B and C have both optical transmission / reception modules for replacement as described above. The optical boards 201 and 202 must be replaced. Therefore, there is no choice but to stop the system.

The same problem occurs when it is necessary to replace the optical transceiver module, such as when switching the transmission frequency band between some nodes.

[Object of the Invention]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical data transmission device which solves the above-mentioned problems associated with replacement of an optical transceiver module and facilitates expansion and switching of transmission frequency bands.

[Outline of Invention]

The present invention provides an optical board for mounting an optical receiver module in an optical data transmission device, an optical transmission / reception module for receiving an optical signal from an active transmission line, and a standby transmission in which the signal transmission direction is opposite to that of the active transmission line. A first optical board having an optical transmission module for transmitting an optical signal to the optical path, an optical transmission module for transmitting an optical signal to the active transmission path, and an optical receiving module for receiving an optical signal from the standby transmission path A second optical board, and each of the first and second optical boards is either long-wavelength transmission or short-wavelength transmission, depending on a distance from an adjacent partner transmission device on the transmission path. The optical transmitter module and the optical receiver module having the characteristics described above are mounted. As a result, even if it is necessary to operate the long wavelength module and the short wavelength module in combination due to the difference in the distance between the optical data transmission devices,
The optical transceiver module can be replaced while the system is operating, such as when adding equipment.

[Embodiment of the Invention] An embodiment of the present invention will be described in detail below.

FIG. 1 shows a schematic configuration of an optical data transmission device according to an embodiment of the present invention. In this figure, the same parts as those in FIGS. 2 and 3 are designated by the same reference numerals.

As shown in the figure, in the present embodiment, one optical board 201, which is a physical unit for exchange, is provided with the active transmission line 104.
Optical receiving module 203 for receiving optical signals from the
An optical transmission module 205 for transmitting an optical signal to the standby system transmission line 105 whose signal transmission direction is opposite to that of the active system transmission line 104 is mounted. The other optical board 202
An optical receiving module 206 for receiving an optical signal from the standby system transmission line 105 and an optical transmitting module 204 for transmitting an optical signal to the active system transmission line 104 are mounted on the. That is, the active optical transceiver module 204,
203 are separately mounted on the optical boards 202 and 201, respectively.
05 and 206 are also physically separated and mounted. Further, as the optical receiving module 203 and the optical transmitting module 205 mounted on the optical board 201, modules for long wavelength transmission or short wavelength transmission are used. This is the module 204, 2 of the optical board 202.
The same applies to 06.

Because of the mounting form of such an optical transceiver module,
As described below, optical transmission with the system running,
The receiving module can be replaced.

For example, it is assumed that the optical data transmission device of this embodiment is used as the nodes A, B and C of the optical loop network shown in FIG. The transmission between the nodes is assumed to be short wavelength transmission. In such a system, it becomes necessary to add a node D as shown in FIG.
The transmission between the nodes B and C is assumed to be long wavelength transmission.

In this case, first, the system before the expansion is operated in the loopback state as shown in FIG. Then, as the node D, the optical transceiver modules 203 to 206 for long wavelength transmission
The optical data transmission device of the present embodiment in which is mounted is prepared, and the optical transmission / reception modules 203 to 206 are connected to the transmission lines 502, 5
03 (Fig. 5).

On the other hand, the optical board 202 of the node B is replaced with the optical transmission / reception module for long wavelength transmission mounted, and the optical transmission / reception modules 204 and 206 are connected to the additional transmission lines 502,
503 respectively. Similarly, the optical board 201 of the node C is replaced with one for long wavelength transmission, and the optical transmission / reception modules 203 and 205 are added to the additional transmission lines 502 and 503.
Connect with. This completes the expansion work.

Here, when the optical board 202 of the node B is replaced, the optical receiving module 203 and the optical transmitting module 205 on the optical board 201 receive and transmit an optical signal. When the optical board 201 of the node C is replaced, optical signals are transmitted and received by the optical transmission / reception modules 204 and 206 of the optical board 202. Therefore, the replacement work of the optical transmission / reception module accompanying the expansion can be performed while the system is operating in the loopback state shown in FIG.

〔The invention's effect〕

As is apparent from the above description, according to the present invention, due to the difference in the distance between the optical data transmission devices and the like, even when it is necessary to operate the long wavelength and the short wavelength for the optical transceiver module in combination, The optical transmission / reception module of the device can be exchanged while the system is operating, and there is an effect that expansion and transmission frequency band switching can be performed more easily than before.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an optical data transmission device according to an embodiment of the present invention, FIG. 2 is a system configuration diagram showing an example of an optical network system, and FIG. 3 is a schematic configuration diagram of a conventional optical data transmission device, FIG. 4 is a system configuration diagram showing a loopback state of the optical loop network system shown in FIG. 2, and FIG. 5 is a system configuration showing a system configuration after adding an optical data transmission device to the network system of FIG. It is a figure. 101 ... ...... Expansion working system transmission line, 503 ...... Expansion standby system transmission line, 201, 202 ...... Optical board, 203 ......
Active optical receiving module, 204 ... Active optical transmitting module, 205 ... Standby optical transmitting module, 206 ...
… Standby optical receiver module, 207 …… Basic part.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yasuhiro Takahashi 1099 Ozenji, Tama-ku, Kawasaki City, Kanagawa Inside Hitachi Systems Development Laboratory, Ltd. (56) Reference JP-A-60-203039 (JP, A) JP Patent Sho 55-136742 (JP, A) Japanese Patent Sho 53-29463 (JP, B2)

Claims (1)

[Claims] 1. An optical data transmission apparatus for forming an optical loop network system by being connected to a loop-shaped transmission line formed by optical fibers of a working system and a standby system, the signal transmission directions of which are opposite to each other. First optical board mounted with an optical receiving module for receiving an optical signal from the optical system and an optical transmitting module for transmitting an optical signal to the standby transmission line, an optical transmitting module for transmitting an optical signal to the active transmission line, and a standby transmission A second optical board on which an optical receiving module for receiving an optical signal from the optical path is mounted, and the first and second optical boards are respectively
An optical data transmission device in which an optical transmission module and an optical reception module having either one of long-wavelength transmission and short-wavelength transmission characteristics are mounted according to the distance from an adjacent transmission device on the transmission line.