JPH04151918A - Optical communication system with automatic output luminous energy adjustment function - Google Patents

Abstract

PURPOSE:To allow two stations to receive an optical signal having the same intensity with simple constitution by allowing one of optical transmitters provided each with a transmission section and a reception section and coupled with an optical transmission line to measure a reception level and to send a measured value while multiplexing it so as to adjust the transmission level of the other optical transmitter. CONSTITUTION:An optical signal sent from a transmission section 350 of one of optical transmitters each provided with a transmission section 350 and a reception section 550 and coupled with an optical transmission line is received by the reception section 550 of the other optical transmitter and a level measurement device 450 measures the reception level. The measured value is multiplexed by a multiplexer section of the transmission section of the other optical transmitter and the multiplexed signal is sent, and the sent signal is demultiplexed at a multiplexer/demultiplexer section of the reception section 500 of the one optical transmitter to adjust an amplification factor of an amplifier section of the transmission section 350 of the optical transmitter. The amplification factor of the transmission section 350 of the other optical transmitter is similarly adjusted and the two stations receive the optical signals having the same intensity with simple constitution.

Description

[Detailed Description of the Invention] [Summary] Regarding an optical communication system that automatically adjusts the amount of input light between two stations each having a transmitter/receiver, it is possible to generate optical signals of the same strength at all times at the receivers of the two stations at a low cost. The purpose is to provide an optical communication system with an automatic output light amount adjustment function that can receive the following information: The receiving section converts the optical signal data received from the optical transmission path into electrical signal data and then multiplexes it. In an optical communication system that sends and receives main signal data between two optical transmission devices that have the function of separating data, the receiving section measures the level of electrical signal data converted from optical signal data, and the transmitting section measures the level of electrical signal data converted from optical signal data. A level measuring section is provided to add the level measuring section to the transmitting section of one optical transmission device, and the level measurement value of the output of the level measuring section is multiplexed and output together with the main signal data, and the receiving section of the opposite optical transmission device multiplexes and outputs the level measurement value. The level measurement value is separated from the input data, and the transmitter adjusts the amplification gain based on the level measurement value, so that the amount of input light at the receiver of one of the optical transmission devices becomes constant.

[Industrial application field]

The present invention relates to an optical communication system that automatically adjusts the amount of input light between two stations each having a transmitting/receiving section.

At this time, there is a need for a low-cost optical communication system with an automatic output light amount adjustment function that allows two receivers to always receive optical signals of the same intensity.

[Conventional technology]

FIG. 3 is a block diagram showing the configuration of an example optical communication system.

In a system that transmits and receives optical signals between stations A and B via an optical transmission line as shown in Figure 3, station A uses a multiplexing device (hereinafter referred to as MUX) to multiplex main signal data of multiple channels. to multiplex the output to electrical/amplifier 2.
In addition to the optical conversion circuit (hereinafter referred to as E10) 3, the electrical signal was converted into optical signal data and the output optical signal data was sent to the optical transmission line.

In this case, when using a laser diode 1 (hereinafter referred to as LD, not shown) as E103, by adding the rear output light of the LD to amplifier 2 and performing automatic gain control on the output light of E103, E103 The output light was kept constant. Furthermore, when the rear output light received by the amplifier 2 is large, an optical attenuator is used to control the output light of the E103 to be constant.

On the other hand, at the opposite station, the optical signal data from the optical transmission line is
It is received by an electrical conversion circuit (hereinafter referred to as 0/E) 6 and converted into electrical signal data, and the output is sent to a multiplexing/demultiplexing device (hereinafter referred to as D).
(referred to as MUX) 7 and also separated multiplexed data.

In the transmitting section of station B and the receiving section of station A, a series of A
The transmitting section of the station and the receiving section of the B station operated in the same way.

[Problem to be solved by the invention]

However, the above-mentioned system has the problem that an optical attenuator must be used when the optical output is large, which increases cost.

Therefore, an object of the present invention is to provide a low-cost optical communication system with an automatic output light amount adjustment function that allows two receivers to always receive optical signals of the same intensity.

[Means to solve the problem]

The above problem is solved by the system configuration shown in FIG.

That is, in FIG. 1, they are connected to each other by an optical transmission line,
Each of them has a transmitting section 350 and a receiving section 550, and the transmitting section has a function of multiplexing and amplifying main signal data, converting the electrical signal data into optical signal data, and sending it out to the optical transmission line. The receiving unit is an optical communication device that sends and receives main signal data between two optical transmission devices that have the function of converting optical signal data received from an optical transmission line into electrical signal data and then separating the multiplexed data. In the system, 450
is a level measuring section provided in the receiving section 550, which measures the level of electrical signal data converted from optical signal data and adds it to the transmitting section.

Then, the transmitting section 350 of one optical transmission device multiplexes the level measurement value output from the level measuring section 450 with the main signal data and outputs the multiplexed level measurement value.

On the other hand, the receiving section 550 of the opposing optical transmission device separates the level measurement value from the multiplexed input data, and the transmitting section 350 separates the level measurement value from the multiplexed input data.
The amplification gain is adjusted based on the level measurement value, so that the amount of input light at the receiving section 550 of one optical transmission device becomes constant.

[For production]

In FIG. 1, optical signal data is converted into electrical signal data by, for example, an optical/electrical converter in a receiving section 550 of one optical transmission device, and this output is input to a level measuring section 450 to measure the level, and then the signal is transmitted. For example, it is added to the multiplexing section of section 350.

In the multiplexing section, the level measurement value of the output of the level measurement section 450 is inserted into the control bits, multiplexed with the main signal data, and the output is applied to an electrical/optical conversion section via an amplification section, for example, to convert it into optical signal data. After conversion, it is sent to an optical transmission line.

On the other hand, a level measurement value inserted into the control bit from the multiplexed input data is separated from the main signal data by, for example, a demultiplexing section of the opposing optical transmission device, and is applied to, for example, an amplifying section of the transmitting section. Then, the amplification section adjusts the amplification gain based on the level measurement value so that the amount of input light at the reception section 550 of the other optical transmission device becomes constant.

As a result, by adding a simple circuit (i.e., at low cost)
, it becomes possible to always receive optical signals of the same strength at the receiving sections of two opposing optical transmission devices.

〔Example〕

FIG. 2 is a block diagram showing the configuration of an optical communication system according to an embodiment of the present invention.

The same reference numerals refer to the same objects throughout the design.

In Figure 2, O/E60 and DMUX of the receiving section of B station
A level measuring circuit 65 provided between the optical transmission line 71o measures the input power (which is proportional to the amount of input light) converted into electrical signal data from the optical transmission line via the O/E 60. This measured value is added to the MUX 95 of the transmitter in the same eight stations, inserted into, for example, an overhead pit as a control bit, and multiplexed with the main signal data. This M U
The output of the X95 is applied to the E1080 via the amplifier 90 and converted into optical signal data, and then the output is sent to the optical transmission line.

On the other hand, at station A, the optical signal data from the optical transmission line is received by the O/E 50 of the receiving section and converted into electrical signal data.

Then, as in the case of B station, O/E50 and DMUX4
The output of 0/E50 is added to the level measuring circuit 45 provided between 0 and 0 to measure the amount of received power (this is proportional to the amount of light received).

At the same time, the output of 07E50 passes through the level measuring device 45 as it is and is added to the DMUX 40, and the output of the 07E50 is added to the DMUX 40, and the B
The measured values measured by the level measuring circuit 65 of the receiving section of the station are separated. This measured value is added to the amplifier 20 of the transmitting section of the A station, and the gain of the amplifier 20 is automatically controlled according to the measured value so that the amount of input light at the O/E 60 of the receiving section of the B station is constant. Then, a certain amount of optical signal data is output from the E1030. As a result, the O of the receiving section of B station is
The amount of input light at /E6Q is constant.

Also, the value of the received power amount measured by the level measurement circuit 45 of the receiving section of the A station described above is added to the MUXIO of the transmitting section, and is inserted into the overhead pit as a control bit, for example, as in the transmitting section of the B station described above. and multiplexed with the main signal data. Amplify the output of this MUXIO to 20
After converting it into optical signal data via E1030, the output is sent to an optical transmission line.

Incidentally, the above-mentioned level measuring circuits 45, 65 can be easily made using, for example, an IC or the like.

In this way, by adding a simple circuit (that is, at low cost), it is possible to always receive optical signals of the same strength at the receiving sections of the two stations.

〔Effect of the invention〕

As explained above, according to the present invention, by adding a simple circuit (that is, at low cost), it is possible to always receive optical signals of the same strength at the receiving sections of two stations.

[Brief explanation of drawings]

FIG. 1 is a diagram of the principle of the present invention, and FIG. 2 is a +N? of an optical communication system according to an embodiment of the present invention. FIG. 3 is a block diagram showing the structure of an example optical communication system. In the figure, 450 indicates a level measuring section.

Claims (2)

[Claims] (1) They are connected to each other by an optical transmission line, and each has a transmitting section (350) and a receiving section (550), and the transmitting section multiplexes and amplifies the main signal data and converts the electrical signal data into an optical signal. The receiving section has a function of converting the optical signal data received from the optical transmission path into electrical signal data and then separating the multiplexed data. In an optical communication system that transmits and receives main signal data between two optical transmission devices, a level measurement device is used in the receiving section (550) to measure the level of electrical signal data converted from optical signal data and to apply the level to the transmitting section. The transmission section (350) of one optical transmission device multiplexes and outputs the level measurement value of the output of the level measurement section (450) together with the main signal data, and The receiving unit (550) separates the level measurement value from the multiplexed input data, and sends the level measurement value to the transmitting unit (550).
50), the amplification gain is adjusted based on the level measurement value so that the input light amount at the receiving section (550) of the one optical transmission device is constant. system. (2) The level measurement value of the output of the level measurement section (450) and the main signal data are multiplexed by the level measurement section (450).
2. The optical communication system with an automatic output light amount adjustment function according to claim 1, wherein the level measurement value of the output of 0) is inserted into the control bit and multiplexed with the main signal data.