JP2001168840A - Wavelength multiplex transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength multiplex transmitter that can smoothly transmit control data, using a simple configuration. SOLUTION: A transmission band 32 for control data used to control and monitor a state of the wavelength multiplex transmitter is assigned to a band at the outside of a transmission band 31 of communication data through a communication channel, an optical signal resulting from multiplexing the control data and the communication data is sent to an optical fiber 151, the multiplexed signal consisting of the communication data and the control data obtained by receiving the optical signal from the optical fiber 152 is divided into frequency bands to extract the control data. Thus, the control data are transmitted between the wavelength multiplex transmitters.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wavelength division multiplexing transmission apparatus which transmits signals by a plurality of wavelengths by allocating transmission signals of a plurality of communication lines to lights of a plurality of wavelengths, and more particularly, to a control device which has a simple structure and can smoothly control data. The present invention relates to a wavelength division multiplexing transmission device capable of transmitting data to a computer.

[0002]

2. Description of the Related Art In recent years, the amount of information on a network has been rapidly increasing due to the spread of the Internet and the use of multimedia in information devices. For this reason, higher-speed networks and repeaters are required. As a means for speeding up the network, there is a method using an optical fiber. However, if an optical fiber is laid for each communication line, the introduction cost increases and there is a problem. Therefore, wavelength multiplexing transmission, in which a transmission signal of a plurality of communication lines is transmitted by, for example, one optical fiber, by assigning different optical wavelengths to each communication line and wavelength-multiplexing the optical signal of each wavelength, has attracted attention. .

FIG. 4 shows a configuration example of a general network using a wavelength division multiplex transmission apparatus.

As shown in the figure, a plurality of repeaters 421 to 42n and 441 to 44n of communication lines are connected to each other by two optical fibers 46 via wavelength division multiplex transmission devices 411 and 412. WDM transmission devices 411, 412
Are the relay devices 421 to 42n and 441 to 44n, respectively.
And transmission lines (communication lines) 431 to 43n and 451, respectively.
４５45n. Repeaters 421 to 42n and repeaters 441 to 44n without using a wavelength multiplex transmission device
When communication is performed between the communication device and the communication device, communication using various protocols such as Ethernet and ATM and transmission speeds different from each other are performed, so that the number of transmission paths corresponding to the number of connections is required. However, by using the wavelength multiplexing transmission devices 411 and 412, allocating the transmission signals of the respective communication lines to light of different wavelengths, and multiplexing these optical signals for transmission, it is possible to relay with a small number of optical fibers. Devices can be connected.

FIG. 5 shows the internal configuration of a wavelength division multiplex transmission apparatus. The wavelength multiplex transmission device 51 includes wavelength conversion units 521 to 52
n, a wavelength multiplexing unit 53, and a wavelength demultiplexing unit 54. The wavelength multiplexing unit 53 and the wavelength demultiplexing unit 54 have an AWG (Array
Optical passive components such as ed Waveguide Grating) are used. The wavelength conversion units 521 to 52n include ports 1 to N for connecting to an external relay device, and transmission units 561 to 56.
n, and receiving units 571 to 57n are mounted. Port 1
To N convert a signal received from an external relay device into an electric signal and send it to the transmission units 561 to 56n. Transmission units 561 to 5
6n converts an input electric signal into an optical signal having a wavelength determined for each port, and converts this optical signal into an optical fiber 58.
Is transmitted to the wavelength multiplexing unit 53. Wavelength multiplexing unit 53
Then, the optical signals transmitted from the transmission units 561 to 56n are wavelength-multiplexed, and the wavelength-multiplexed signals are transmitted using the optical fiber 551.

Next, the receiving operation will be described. The wavelength demultiplexing unit 54 that has received the wavelength multiplexed signal input from the optical fiber 552 demultiplexes the signal into the respective wavelengths and sends each signal to the receiving units 571 to 57n. Receivers 571-57
In n, the optical signal is converted into an electric signal, and each electric signal is sent to ports 1 to N. Each of the ports 1 to N converts the received electric signal into a signal that satisfies the communication method connected thereto and transmits the signal to an external relay device.

FIG. 6 shows transmission units 561 to 56n and reception unit 5
5 shows the internal circuit configuration of the internal circuits 71 to 57n.

[0008] The transmitting section 65 comprises an LD module, an optical output control circuit 63, and an LD drive circuit 64. The LD module as a light source is an LD (laser diode) 6
2 and a monitor PD (photodiode) 61. The light output control circuit 63 controls the bias current of the LD 62 so that the received light power of the monitor PD 61 becomes constant. By modulating the optical output of the LD 62 in this manner, the electrical signal is converted into an optical signal and output. Communication data for modulating the optical output is controlled by the LD drive circuit 64 and input to the LD 62 as an electric signal.

The receiving section 67 includes a PD 65 and a signal reproducing circuit 6.
6. The receiving section 67 receives the input optical output by the PD 65 and converts the electric signal into a signal reproduction circuit 6.
6, and is converted into communication data.

[0010]

When the wavelength division multiplexing transmission apparatus needs to grasp the state of the other apparatus (type of each port, abnormality inside the apparatus, etc.), control data indicating the state of the apparatus is transmitted. The wavelength multiplex transmission devices must communicate with each other. For this reason, conventionally, it was necessary to provide a communication port for control data separately from the communication port for communication data. When a wavelength for wavelength division multiplexing is allocated to the control data signal, an extra wavelength is allocated to a finite communication data transmission band, so that the number of wavelengths for communication data decreases and the wavelength utilization efficiency deteriorates. . Also,
Since a transceiver for control data communication is required, the cost of the wavelength division multiplexing transmission device increases.

An object of the present invention is to solve the above-mentioned problems and to provide a wavelength multiplex transmission apparatus capable of smoothly transmitting control data with a simple configuration.

[0012]

In order to achieve the above object, the present invention has a plurality of input / output ports connected to a plurality of communication lines, and allocates transmission signals of each communication line to light of different wavelengths. In a wavelength division multiplexing transmission apparatus which wavelength-multiplexes these optical signals and transmits signals through a smaller number of optical fibers than the above communication line, the state of the wavelength division multiplexing transmission apparatus is controlled and monitored outside the transmission band of communication data in the communication line. A transmission band of control data to be transmitted is allocated, an optical signal obtained by multiplexing the control data and communication data is transmitted to an optical fiber, and a multiplexed signal of communication data and control data obtained by receiving an optical signal from the optical fiber is received. Is divided into bands to extract control data, thereby transmitting control data between wavelength division multiplexing transmission apparatuses.

[0013] The drive signal of the light emitting element may be modulated by the communication data, and the average current of the light emitting element may be modulated by the control data to generate an optical signal in which the control data and the communication data are multiplexed.

[0014]

An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows the internal configuration of a wavelength division multiplex transmission apparatus using the present invention. The wavelength multiplexing transmission device 11 includes wavelength conversion units 121 to 12n, a wavelength multiplexing unit 13, a wavelength demultiplexing unit 14,
Control circuit 191, state monitoring circuit 192, signal control circuit 1
01 to 10n. 5 is different from the conventional wavelength multiplex transmission apparatus of FIG. 5 in that a control circuit 191 and a state monitoring circuit 192 are added, signal control circuits 101 to 10n are added on wavelength converters 121 to 12n, and transmission units 161 to 16n and a reception unit are added. That is, the internal configuration of 171 to 17n is different. A network using the wavelength division multiplexing transmission apparatus of FIG. 1 can have, for example, the configuration of FIG.

The control circuit 191 and the state monitoring circuit 192 are connected by a data bus so that the control circuit 191 and the state monitoring circuit 192 can transfer data to each other. Then, the state monitoring circuit 19
2 is the state of the wavelength division multiplex transmission device (the type of each port,
Abnormalities inside the device) can be collected as control data. The collected control data is transferred to the control circuit 191, and the control circuit 191 transmits the control data to each wavelength conversion unit 12.
It is sent to the signal control circuits 101 to 10n on 1 to 12n.

FIG. 2 shows an internal circuit configuration of the transmitting units 161 to 16n and the receiving units 171 to 17n of the wavelength division multiplex transmission apparatus of FIG.

The transmitting section 28 includes an LD module, an optical output modulation control circuit 23, and an LD drive circuit 24.
The LD module serving as a light source includes the LD 22 and the monitor PD 2.
And 1. The difference from the conventional transmitting unit of FIG.
Conventionally, the optical output control circuit 63 for keeping the optical output signal of the LD module constant is provided, whereas the present invention is provided with the optical output modulation control circuit 23 having a function of modulating the bias current. The optical output modulation control circuit 23 converts the control data signal transferred from the signal control circuit 27 into a bias current modulation signal. By combining the control data signal and the communication data signal controlled by the LD drive circuit 24, an optical signal in which the control data and the communication data are multiplexed can be transmitted.

FIG. 3 shows a frequency spectrum of an optical signal transmitted from the transmitting units 161 to 16n. The transmission band 31 of the communication data is set in a range from a predetermined lower limit frequency to an upper limit frequency in consideration of the transmission speed of the communication line and the like. The control data is transmitted using a transmission band 32 lower than the transmission band of the communication data. Thus, instead of allocating the control data signal wavelength within the communication data transmission band, the control data transmission band 32 is allocated outside the communication data transmission band, and the control data is transmitted at a signal wavelength different from the communication data. Since transmission is performed, control data and communication data can be transmitted simultaneously without reducing the number of communication data wavelengths.

2 includes a PD 25, a signal reproducing circuit, and a control signal demodulating circuit 26. FIG.
The difference from the conventional receiving unit is that by adding a control signal demodulation circuit 26, the optical signal received by the PD 25
It has a function of demodulating a modulated signal. The signal reproducing circuit can extract the electric signal of the communication data as in the conventional case. On the other hand, the control signal demodulation circuit 2
In 6, the demodulated control data signal can be demodulated. The signal demodulated by the control signal demodulation circuit 26 is transferred to the signal control circuit 27, and the control data is sent from the signal control circuit 27 to the control circuit 191 in FIG. This control data is transferred to the state monitoring circuit 192 in FIG. As a result, the state monitoring circuit 192 recognizes the state of the other device.

In the above embodiment, each wavelength converter 1
Transmitting units 161 to 16n mounted for each of 21 to 12n,
The receiving units 171 to 17n are connected to the control circuit 191.
7n can transmit and receive a modulation signal (control data). However, in practice, the present invention can be realized if there is a transmitter and a receiver on any one wavelength converter, and it is not necessary to use all the wavelength converters for transmitting and receiving control data.

[0022]

The present invention exhibits the following excellent effects.

(1) Information can be easily transmitted between wavelength division multiplex transmission apparatuses, and information (type of each port, connection status, etc.) can be exchanged between the respective wavelength division multiplex transmission apparatuses. It can be used effectively for construction etc.

(2) Even when wavelength-division multiplex transmission of communication data is performed, the control signal is transmitted as a modulation signal, so that there is no danger of communication data communication being interrupted.

(3) Since a simple circuit can be used, a low-cost wavelength division multiplex transmission apparatus can be provided.

[Brief description of the drawings]

FIG. 1 is an internal configuration diagram of a wavelength division multiplex transmission device according to an embodiment of the present invention.

FIG. 2 is an internal configuration diagram of a transmission unit and a reception unit of the wavelength division multiplex transmission device of FIG.

FIG. 3 is a frequency spectrum diagram of a signal transmitted through an optical fiber according to the present invention.

FIG. 4 is a configuration diagram of a network using a wavelength division multiplex transmission device.

FIG. 5 is an internal configuration diagram of a conventional wavelength division multiplex transmission device.

6 is an internal configuration diagram of a transmission unit and a reception unit of the wavelength division multiplex transmission device of FIG.

[Explanation of symbols]

 Reference Signs List 13 wavelength multiplexing unit 14 wavelength demultiplexing unit 21 monitor PD 22 LD 23 optical output modulation control circuit 24 LD drive circuit 25 PD 26 control signal demodulation circuit 27 signal control circuit 101 to 10n signal control circuit 121 to 12n wavelength conversion unit 161 to 16n Transmitters 171 to 17n Receiver 191 Control circuit 192 State monitoring circuit

Claims (2)

[Claims] 1. A communication system comprising: a plurality of input / output ports connected to a plurality of communication lines; a transmission signal of each communication line being assigned to light of a different wavelength; In a wavelength division multiplex transmission device that transmits signals over a number of optical fibers, a transmission band of control data for controlling and monitoring the state of the wavelength division multiplex transmission device is allocated outside the transmission band of communication data in a communication line, and the control data and the communication data Wavelength division multiplex transmission by transmitting an optical signal multiplexed with the control signal to an optical fiber, receiving the optical signal from the optical fiber, dividing the multiplex signal of communication data and control data obtained from the optical signal into control bands, and extracting control data. A wavelength division multiplex transmission device for transmitting control data between devices. 2. An optical signal in which control data and communication data are multiplexed is generated by modulating a drive signal of a light emitting element with communication data and modulating an average current of the light emitting element with control data. The wavelength division multiplex transmission device according to claim 1.