JP3141763B2 - Optical communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical communication device for transmitting and receiving an optical signal, and more particularly to an optical communication device for preventing a reduction in the reception level of an optical signal and a disconnection of the optical signal.

[0002]

2. Description of the Related Art In an optical communication apparatus that performs communication through an optical fiber, the intensity of an optical signal transmitted from a transmitting station is adjusted so that the intensity of an optical signal received by an opposite station falls within an appropriate range. It has become. The intensity of an optical signal received by a receiving station is called a reception level, and the intensity of an optical signal sent from a transmitting station is called a transmission level.

[0003] Japanese Patent Application Laid-Open No. 4-269023 discloses an optical communication apparatus in which the transmission level of an optical signal to be transmitted to an opposite station is adjusted based on the reception level of an optical signal received from the opposite station. Have been. One station always transmits an optical signal at a constant transmission level (light intensity). The other station receiving the signal calculates the attenuation of the light intensity in the transmission path from the opposite station to the own station based on the reception level. Then, assuming that the amount of attenuation is equal to the amount of attenuation in the transmission path from the own station to the opposite station, an optical signal is transmitted at a transmission level such that the reception level at the opposite station becomes a predetermined reference value. It has become.

Japanese Patent Application Laid-Open No. 63-76489 discloses that
There is disclosed an optical communication device that monitors the intensity of an optical signal transmitted from its own station and adjusts the transmission level of an optical signal transmitted from the own station to an opposite station so that the transmission level becomes constant.

[0005] The reception level of an optical signal may be significantly reduced due to the deterioration of the light emitting element or optical fiber due to aging or the optical axis shift of the light emitting element and the light receiving element due to various vibrations. When the reception level decreases, the optical signal may not be received normally or the communication may be interrupted. Therefore, the receiving station monitors the reception level of the optical signal, and warns the administrator when the reception level falls below a certain value or the optical signal is interrupted.

FIG. 2 shows an outline of the configuration of a conventionally used optical communication device. The optical signal is transmitted bidirectionally between the first optical communication device 101 and the second optical communication device 102. An optical signal traveling from the first optical communication device 101 to the second optical communication device 102 is transmitted through the first optical fiber cable 103. On the other hand, an optical signal traveling from the second optical communication device 102 to the first optical communication device 101 is transmitted through the second optical fiber cable 104.

Each of the first optical communication device 101 and the second optical communication device 102 converts an electric signal representing information to be transmitted to the opposite station into an optical signal.
1, 112. Also, an optical signal receiving an optical signal sent from the opposite station and outputting an electric signal corresponding to the received optical signal.
It has electrical converters 113 and 114. Monitoring unit 115, 1
Reference numeral 16 denotes a circuit for monitoring whether or not the level of the output signal of the corresponding optical-to-electrical converter, that is, whether the reception level from the opposite station has dropped below a certain value. Monitoring unit 115,
Reference numeral 116 outputs predetermined warning signals 117 and 118 when the reception level falls below a certain value.

[0008] The warning signals 117 and 118 are input to monitoring and control devices 121 and 122 for managing the operation state of the communication device, respectively. Display devices 123 and 124 such as displays are connected to the monitoring control devices 121 and 122, and a warning that the reception level has been lowered is displayed through these devices.

[0009]

Problems to be Solved by the Invention
In the prior art disclosed in Japanese Patent Publication No. 9, since the transmission level on the transmission device side is kept constant, even if the reception level decreases due to deterioration of various circuit elements inside the transmission path and the reception side device, This cannot be compensated. Also, as disclosed in Japanese Patent Application Laid-Open No.
If the transmission level of one station is kept constant and the transmission level to the other station is adjusted based on the reception level of the other station, the reception level of one station can be made appropriate. However, since the transmission level of this station is kept constant, there is a problem that the reception level of the other station cannot be kept properly.

[0010] Further, in a device which issues a predetermined warning when the reception level falls below a certain value, the reception level is reduced from when this warning is issued until the end of the corresponding maintenance. There is a problem that a state or a state where communication is disconnected occurs.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical communication device capable of correcting a decrease in reception level and ensuring proper communication.

[0012]

According to the first aspect of the present invention, a first optical signal receiving means for receiving an optical signal, and an optical signal receiving level based on an output signal of the first optical signal receiving means. Level detecting means for detecting the average of the received levels detected by the received level detecting means
Average value calculating means, and the average value calculated by the average value calculating means.
First optical signal transmitting means for transmitting an optical signal representing the average value of the received reception level to a device from which the optical signal received by the optical signal receiving means is transmitted, and an optical signal at the first optical signal receiving means of
If the reception level is within the
Has fallen below a lower limit than the specified reference value.
A first communication device having a display unit for displaying a warning that the reception level has dropped, and a second optical signal reception unit for receiving an optical signal transmitted from the first communication device. A second optical signal transmitting means for converting information to be transmitted to the first communication device into an optical signal and transmitting the optical signal to the first optical signal receiving means, and an output signal of the second optical signal receiving means The first shown
Allowable reception level of the reception of the optical signal in the optical signal receiving means
A second communication device having transmission level changing means for increasing the transmission level of the optical signal transmitted by the second optical signal transmission means when the value falls within the range and becomes equal to or less than the allowable value. ing.

That is, according to the first aspect of the present invention, the first communication means detects the reception level of the optical signal transmitted from the second communication means, and the average level is calculated by the average value calculation means.
Calculate the value. Then, this is notified to the first communication means by an optical signal. Also, the optical signal in the first optical signal receiving means is
If the reception level of the signal is within the
If the value falls below the allowable value lower than the predetermined reference value,
Warning display on the display means that the reception level has dropped
I do. The second communication means is an average value of the reception level at the first communication means notified by the optical signal from the first communication means.
Is within the permissible reception range and falls below the permissible value,
The transmission level of the optical signal transmitted to the first communication means is increased. Since the average value of the optical signal reception level in the first communication means is notified to the second communication means,
The communication means can adjust the transmission level of the optical signal within an allowable reception range so that the reception level of the first reception means becomes an appropriate value.

According to the second aspect of the present invention, there is provided an optical signal receiving means for receiving an optical signal, and a first level which detects and indicates the reception level of the optical signal received by the optical signal receiving means.
Receiving level detecting means for outputting the receiving level indicating signal of the receiving level, and the receiving level detected by the receiving level detecting means.
An average value calculation means for calculating a mean value of the bell, the average value calculation
Multiplexing means for multiplexing the first received level average value display signal output by the output means and a main signal representing information to be transmitted to the transmission source apparatus of the optical signal received by the optical signal receiving means; an optical signal transmitting means for transmitting to the device the sender is converted to an optical signal the output signal of the multiplexing means, an optical signal receiver
The receiving level of the optical signal at the means is within the
And lower than the predetermined reference value
Warning table that the reception level has dropped when it drops below
And Shimesuru display means, the optical receiver of the optical signal transmitted from the transmitting means in the transmission source of the device included in the optical signal received by the optical signal receiving means by being multiplexed with transmission source apparatus a reception level average value display signal extracting means for extracting a second reception level average value display signal represents the level from the output signal of the optical signal receiving means, average the received level
The reception level at the transmission source device indicated by the second reception level average value display signal extracted by the value display signal extraction means is
The optical communication device is provided with a transmission level changing means for increasing the level of the optical signal transmitted by the optical signal transmitting means when the optical signal is within the allowable range of reception and is equal to or less than the allowable value.

That is, according to the second aspect of the present invention, the average value of the reception level of the optical signal transmitted from the opposite station is detected, and the data representing the average value and the main signal are multiplexed. Then, the multiplexed signal is converted into an optical signal and transmitted to the opposite station. Also, the reception of the optical signal by the first optical signal receiving means
Make sure that the level is within the
Received when the value falls below a lower limit than the specified reference value.
A warning is displayed on the display means that the communication level has dropped. Change
In addition, the optical signal transmitted from the opposite station includes information indicating the average value of the reception level of the optical signal transmitted from the own station at the opposite station. Therefore, data representing the average value of the reception level at the opposite station is extracted from the received signal, and when this falls within the allowable range of reception and becomes equal to or less than the allowable value, the transmission level of the optical signal to be sent to the opposite station is determined . Is increasing. Accordingly, the transmission level can be adjusted by both opposing optical communication apparatuses so that the reception level at the opposing station becomes an appropriate value. Further, since the data representing the reception level is multiplexed on the main signal, there is no need to separately provide a transmission path for notifying the reception level.

[0016]

[0017]

[0018]

[0019]

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION

[0021]

FIG. 1 shows an outline of the configuration of an optical communication system using an optical communication apparatus according to an embodiment of the present invention. This system includes first and second optical communication devices 11 and 12 having the same configuration for transmitting and receiving optical signals,
There are provided first and second optical fiber cables 13 and 14 for transmitting optical signals between them. Monitoring and control devices 15 and 16 for managing the operation state of each optical communication device are connected. Each monitoring control device 1
Display devices 17 and 18 are connected to 5 and 16 to indicate that a failure such as a decrease in reception level has occurred.

The first optical communication device 11 receives an optical signal sent from the second optical communication device 12 through the second optical fiber cable 14, and converts this into an electric signal corresponding to the light intensity. The optical / electrical conversion unit 21 is provided. The output signal of the optical-electrical conversion unit 21 is input to the optical reception level detection circuit 22 and the demultiplexer 23. The optical reception level detection circuit 22 detects the average intensity of the optical signal received based on the electric signal input from the optical-electrical conversion unit 21, that is, the optical reception level data 24 which indicates the reception level and indicates the magnitude. Output. Optical reception level data 24
A main signal 25 representing data to be transmitted to the second optical communication device 12 is input to a multiplexer 26 for multiplexing these signals.

The multiplexed electrical signal 27 of the main signal 25 and the optical reception level data 24 is input to an electrical / optical converter 28 which converts the multiplexed electrical signal into an optical signal. The optical signal output from the electrical / optical converter 28 is transmitted to the second optical communication device 12 through the first optical fiber cable 13. The light reception level data 24 output from the light reception level detection circuit 22 is
It is input to a monitoring unit 29 for monitoring a decrease in the reception level. The monitoring unit 29 outputs a warning signal 31 indicating a decrease in the reception level when the value of the light reception level data 24 becomes smaller than a predetermined reference value by a certain value or more. When the warning signal 31 is input, the monitoring control device 15 displays on the display unit 17 that the reception level of the optical signal from the second optical communication device 12 has dropped below the allowable value.

The second optical communication device 12 converts an optical signal from the first optical communication device 11 into an electric signal, and an optical / electric conversion unit 32. And an optical reception level detection circuit 34 for detecting optical reception level data and outputting optical reception level data 33. The main signal 3 representing data to be transmitted to the first optical communication device 11
And a multiplexer 36 for multiplexing the optical reception level data 33 and the output signal 37 into an optical signal.
Has an electric / optical conversion unit 38 for transmitting to the optical communication device 11. The electric signal output from the optical-electrical conversion unit 32 is input to the demultiplexer 39.

The light reception level data 33 output from the light reception level detection circuit 34 is input to the monitoring unit 41.
The monitoring unit 41 outputs a warning signal 42 indicating a decrease in the reception level based on the optical reception level data 33 to the monitoring control device 1.
6 is output.

As described above, the reception levels of the optical signals transmitted from the other device are detected, and the optical reception level data representing the detected level and the multiplexed optical signal of the main signal are transmitted to the other device. . Thus, the reception level of each received optical signal is notified to the other device.

The demultiplexer 23 included in the first optical communication device 11 separates the electric signal input from the optical / electrical converter 21 into a main signal component and an optical reception level data component. The optical reception level data 51 output from the demultiplexer 23 is input to an optical transmission level adjustment circuit 52. The optical transmission level signal adjustment circuit 52 is configured to convert the electrical / optical conversion unit 28 based on the value of the input optical reception level data 51.
Is a circuit that adjusts the light intensity of the optical signal output from the control circuit, that is, the transmission level.

Similarly, the demultiplexer 39 of the second optical communication device 12 separates the electric signal input from the optical-electrical conversion unit 21 into a main signal component and a light reception level data component. The separated optical reception level data 53 is input to an optical transmission level adjustment circuit 54 that adjusts the transmission level of the electrical / optical converter 38.

Next, the operation of the optical communication device having such a configuration will be described.

Since the first optical communication device 11 and the second optical communication device 12 have the same configuration and the same operation, the reception level of the first optical communication device 11 is set here. Will be described. The first optical communication device 11 converts an optical signal received from the second optical communication device 12 into an electric signal by the optical / electrical conversion unit 21. The optical reception level detection circuit 22 calculates an average value of the electric signal output from the optical-electrical conversion unit 21, that is, an average value of the optical power, and outputs optical reception level data 24 representing the average value. This will be referred to as first level data 24.
After the first level data 24 is multiplexed with the main signal 25 by the multiplexer 26, it is converted into an optical signal and transmitted to the second optical communication device. That is, the first optical communication device 1 of the optical signal transmitted from the second optical communication device 12
The reception level at 1 is notified to the second optical communication device 12.

The first level data 24 is constantly compared with a predetermined reference value by a comparison circuit (not shown) of the monitoring unit 29. The monitoring unit 29 outputs a warning signal 31 indicating a decrease in the reception level when the first level data 24 becomes lower than the reference value by a certain value or more. In response to this, a display to that effect is displayed on the display unit 17 connected to the monitoring control device 15. Thus, the first optical communication device 11 warns that the reception level of the optical signal from the second optical communication device 12 has fallen below the allowable value.

In the second optical communication device 12, the optical signal sent from the first optical communication device 11 is separated by the demultiplexer 39 into a main signal component and a light reception level data component. That is, the first level data multiplexed by the first optical communication device 11 is
9 to be separated and extracted. Optical transmission level adjustment circuit 54
Has a comparison circuit (not shown), and compares the value of the optical reception level data 53 input from the demultiplexer 39 with a predetermined reference value. Optical transmission level adjustment circuit 54
When the difference between the optical reception level data 53 and the reference value is within a certain range, the electrical-optical converter supplies a control signal corresponding to a preset normal transmission level.

On the other hand, when the value of the optical reception level data 53 becomes smaller than the reference value by a certain amount or more, a control signal for increasing the intensity of the output light from the normal transmission level is supplied to the electrical-optical converter. . As a result, an optical signal having a higher light intensity than usual is output from the electrical / optical converter.

As described above, the reception level in the first optical communication device is notified to the second optical communication device which is the source of the optical signal, and based on this, the second optical communication device side performs the first optical communication device on the first optical communication device side. The transmission level of the optical signal transmitted to the optical communication device is adjusted. That is, when it is detected based on the reception level data sent from the first optical communication device 11 that the reception level at the first optical communication device has fallen below the allowable value, the first optical communication device The transmission level for the communication device is increased.

Here, the transmission level is increased only when the transmission level falls below the allowable value. When the transmission level is controlled based on the reception level data sent from the other party so that the reception level is constant, it is detected that the reception level has decreased due to deterioration of the transmission path and optical circuit elements. This occurs only after the compensation level at the transmission level is exceeded. Therefore, when the warning is issued, even if the transmission level is adjusted, it cannot be restored to an appropriate reception level. By not changing the transmission level while the reception level is within the range of the allowable value, a decrease in the reception level can be detected early and an alarm can be issued. Further, at the time when the warning is issued, the transmission level is increased and the decrease in the reception level is reduced, so that communication at a reception level within an allowable range can be ensured even after the warning is issued. As a result, communication can be performed at a reception level within an allowable range even after the warning is issued and before maintenance corresponding to the warning is performed.

Of course, if the transmission level is constantly changed, the reception level can always be set to an appropriate value. In such a case, it may be warned that the difference between the transmission level and the reception level is larger than an allowable value based on the compensation amount of the transmission level.

[0037]

As described above, according to the first aspect of the present invention, the average value of the reception level of the received optical signal is obtained.
To transmit this to the second communication device of the transmission source.
Therefore, the process when changing the transmission level in the second communication device
Becomes stable. In addition, the optical signal is received by the first optical signal receiving means.
If the reception level is within the
Has fallen below a lower limit than the specified reference value.
Alerts the first communication device that the reception level has dropped
Because we decided to display, even if there was a warning, the reception level
The communication can be performed within the allowable range. And after this
The reception level of the optical signal further falls and falls outside the allowable range
Can be monitored. Further, on the second communication device side
Is the output of the second optical signal receiving means.
The reception level of the optical signal at the first optical signal receiving means indicated by the signal.
Is within the allowable reception range and falls below the allowable value.
The transmission level of the optical signal transmitted by the second optical signal transmitting means is
Communication within the allowable range.
Signal before the level drops outside the allowable range while securing
The effect is that the level can be increased.

Further, according to the second aspect of the present invention, it is possible to adjust the transmission level of both opposing optical communication apparatuses so that the reception level at the partner station becomes an appropriate value. Further, since the data representing the reception level is multiplexed into the main signal, there is no need to separately provide a transmission path for notifying the reception level. Moreover, according to the second aspect of the present invention,
Lights when the reception level at the source device falls below the allowable value.
Increase the transmission level of the optical signal transmitted by the signal transmission means.
Transmission level changing means to reduce the
The transmission level is increased only when this happens. This allows
It is possible to detect a drop in reception level early and issue a warning.
it can. Also, when a warning is issued, the transmission level increases.
Warning that the drop in reception level is reduced.
That communication within the allowable range can be secured even after
Has the effect.

According to the second aspect of the present invention, the reception level
The average value of the reception level detected by the bell detection means
The transmission level is changed because the required average value calculation means is provided.
The processing when performing is stable. Also, the light at the optical signal receiving means
If the signal reception level is within the
Reduced to below tolerances lower than pre-determined reference values
Warning display when the reception level has dropped
Measures have been taken to allow the reception level even after a warning
Communication can be performed within the range. And after that, Koshin
Whether the reception level of the signal falls further out of the allowable range
Can be monitored. Furthermore, the reception level average value display signal
Second reception level average value extracted by signal extraction means
The reception level at the source device indicated by the display signal indicates that the
When the optical signal is
Transmission level to increase the transmission level of the optical signal transmitted by the stage.
Communication means within the permissible range.
Signal level before the level falls outside the allowable range
This has the effect of being able to increase.

[0040]

[Brief description of the drawings]

FIG. 1 schematically shows a configuration of an optical communication system using an optical communication device according to an embodiment of the present invention.

FIG. 2 shows an outline of a configuration of an optical communication system using a conventionally used optical communication device.

[Explanation of symbols]

 11, 12 Optical communication device 13, 14 Optical fiber cable 15, 16 Monitoring control unit 17, 18 Display unit 21, 32 Optical-electrical conversion unit 22, 34 Optical reception level detection circuit 23, 36 Demultiplexer 24, 33 Optical reception level Data signal 25, 35 Main signal 26, 36 Multiplexer 28, 38 Electrical / optical conversion unit 29, 41 Monitoring unit 31, 42 Alarm signal

Continuation of front page (56) References JP-A-2-10929 (JP, A) JP-A-2-198232 (JP, A) JP-A-57-190436 (JP, A) JP-A-4-56431 (JP) JP-A-63-281534 (JP, A) JP-A-62-76331 (JP, A) JP-A-3-34633 (JP, A) JP-A-4-92518 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H04B 10/00-10/28

Claims (2)

(57) [Claims] A first optical signal receiving means for receiving an optical signal; a receiving level detecting means for detecting a receiving level of the optical signal based on an output signal of the first optical signal receiving means; the reception level detected by the level detecting means
Average value calculating means for obtaining an average value, and the average value calculating means
A first optical signal transmitting means for transmitting an optical signal representing the average value of the reception level calculated on sending source device of the received optical signal of the optical signal receiving means by said first Mitsunobu
The reception level of the optical signal in the signal receiving means is within the allowable range of reception.
Within and lower than a predetermined reference value
When the signal level drops below the allowable value,
A first communication device having display means for displaying a warning; a second optical signal receiving means for receiving an optical signal transmitted from the first communication device; and information to be transmitted to the first communication device. Into an optical signal, and transmit the optical signal to the first optical signal receiving means;
The reception level of the optical signal at the first optical signal receiving means indicated by the output signal of the optical signal receiving means is within the allowable range of the reception.
And a transmission level changing means for increasing a transmission level of an optical signal transmitted by the second optical signal transmitting means when the transmission level becomes equal to or less than the allowable value. Optical communication device. 2. An optical signal receiving means for receiving an optical signal, and a receiving level detecting means for detecting a receiving level of the optical signal received by the optical signal receiving means and outputting a first received level indicating signal indicating the detected level. Means and the reception level detected by the reception level detection means
An average value calculation means for calculating an average value, transmits to the sending source device of the received optical signal of the first reception level average value <br/> display signal and said optical signal receiving means for output of the average value calculating means and multiplexing means for multiplexing the main signal represents should do information, an optical signal transmitting means for transmitting to said sending source apparatus is converted into an optical signal the output signal of the multiplexing means, said optical signal The reception level of the optical signal at the receiving means
Reference value or One predetermined be within the allowable range
If the signal level drops below the lower tolerance level,
Display means for displaying a warning that the optical signal is received, and the optical signal transmitting means in the source apparatus included in the optical signal received by the optical signal receiving means by being multiplexed in the source apparatus. A reception level for extracting a second reception level average display signal representing the reception level of the transmitted optical signal from the output signal of the optical signal receiving means.
The average value display signal extracting means, within the allowable range of the receiving level is the reception at the transmission source device indicated by the second reception level average value display signal extracted by the reception level average value display signal extracting means Ah
And a transmission level changing means for increasing a transmission level of the optical signal transmitted by the optical signal transmitting means when the optical signal transmission value becomes equal to or less than the allowable value.