JP2003174413A - Level adjusted wavelength multiplexed light transmitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a level adjusted wavelength multiplexed light transmitting device for making it unnecessary to provide an optical coupler in each transponder side, and for matching the relative level of each wavelength being the target of wavelength multiplex in a simple configuration. <P>SOLUTION: Transponders 1-1 - 1-n are respectively provided with variable optical attenuators 3-1 - 3-n corresponding to each wavelength being the target of wavelength multiplex, and a wavelength multiplexing part 9 for multiplexing an optical signal from each transponder is provided with a detector 14 for detecting a multiplexed light output and an output control part 15 for successively executing first control to set the attenuation of the attenuator of each transponder as a first prescribed value, and for executing second control to set the attenuation of each transponder based on the detection of the detector at the time of controlling the attenuation as the prescribed value. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to wavelength division multiplexing optical transmission in which the output level of each wavelength in wavelength division multiplexing is appropriately adjusted.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram showing a conventional wavelength division multiplexing optical transmission apparatus. In the figure, 1-1 to 1-n are transponder boards for outputting optical signals of wavelengths .lambda.1 to .lambda.n, respectively. , 2-1 to 2-n therein are the electric / optical converters (E / E / E) in the transponder boards 1-1 to 1-n.
O), 3-1 to 3-n are electric / optical converters 2-1 to 2-n.
A variable optical attenuator (VOA) that attenuates an optical signal output from the optical signal to an arbitrary level, and 4-1 to 4-n are variable optical attenuators 3-.
First optical couplers 5-1 to 5-n for branching optical signals output from 1 to 3-n are variable optical attenuators 3-1 to 3-n.
Attenuation control signals for controlling the attenuation of the transponder boards 1-1 to 1-n branched by the first optical couplers 4-1 to 4-n. Signals 7-1 to 7-n are transponder boards 1-
1 to 1-n are transponder output signals. Further, 8 is an optical power meter for measuring the power of the monitor signals 6-1 to 6-n, and 9 is a responder output signal 7-.
1 to 7-n input wavelength-multiplexed board
Reference numeral 0 is a wavelength multiplexing unit for wavelength-multiplexing the transponder output signals 7-1 to 7-n, and 11 is a wavelength multiplexing signal output from the wavelength multiplexing substrate 9.

Next, the operation will be described. In the transponder substrate 1-1, the electric / optical converter 2-1 converts the electric signal into an optical signal of wavelength λ1 and inputs it into the variable optical attenuator 3-1. The output of the variable optical attenuator 3-1 is input to the first optical coupler 4-1 and branched into a monitor signal 6-1 and a transponder output signal 7-1. Here, the following preparatory adjustments are necessary in order to make the outputs of the transponder output signals 7-1 to 7-n output from each transponder substrate to the wavelength division multiplexing substrate the same level. That is, the monitor signal 6
The output level of -1 is measured by the optical power meter 8 and the attenuation amount of the variable optical attenuator 3-1 is controlled by the attenuation amount control signal 5-1 to obtain the transponder output signal 7-1.
Adjust so that the level becomes the specified level. The same operation is performed on the transponder boards 1-2 to 1-n, and the transponder output signals 7-2 to 7-n are adjusted so as to reach a specified level. By adjusting in this way, all the transponder output signals 7-1 to 7-n are adjusted to the specified level and input to the wavelength multiplexing substrate 9, and the wavelength multiplexing unit 1
1 is wavelength-multiplexed, and a wavelength-multiplexed signal 10 is output.

As another conventional example, Japanese Patent Laid-Open No. 11-29884
According to Japanese Patent Laid-Open Publication No. 08-08, in a wavelength division multiplexing optical transmission device, a spectrum analyzer is prepared for each wavelength to be multiplexed, and light is separated for each wavelength to adjust the signal level. As another conventional example, Japanese Patent Laid-Open No. 2000-
According to Japanese Patent No. 332691, an optical signal is branched to an input optical signal from an optical fiber, a detection result is fed back, and a variable optical attenuator is controlled by an attenuator control circuit to keep an optical level constant. Has been done. However, in the former case, it is necessary to divide the wavelength with a spectrum analyzer and adjust the optical level for each specific wavelength, and a spectrum analyzer for wavelength separation is required. In the latter case, since the level of the entire input optical signal is adjusted as one, applying this to wavelength division multiplexing also requires level adjustment separately for each wavelength, which complicates the configuration. Become.

[0005]

The conventional wavelength division multiplexing optical transmission apparatus is configured as described above, and an optical coupler is required on each transponder side in order to adjust the output level of each transponder. Or, there is a problem in that level adjustment is required separately for each wavelength.

The present invention has been made to solve the above problems, and does not require an optical coupler individually on each transponder side, that is, the relative level of each wavelength to be wavelength-multiplexed with a simple structure. A level-adjusting wavelength division multiplexing optical transmission device is obtained.

[0007]

In a level-adjusting wavelength-multiplexing optical transmission device according to the present invention, each transponder is provided with a variable optical attenuator corresponding to each wavelength to be wavelength-multiplexed,
The wavelength multiplexing unit has a configuration in which the optical signals from the respective transponders are multiplexed, and the wavelength multiplexing unit sets the detector for detecting the multiplexed optical output and the attenuation amount of the attenuator of each transponder to a first predetermined value. First, the attenuation amount of each transponder is set based on the detection amount of the detector when the first control is performed so that the value becomes a value, and then the attenuation amount is controlled to the predetermined value.
And an output control unit for controlling the.

Furthermore, the output control unit controls the transponders of the wavelengths to be measured to have the minimum attenuation as the first predetermined value, and simultaneously sets the maximum attenuation to the transponders of other wavelengths. Then, the first control is sequentially performed so that the variable attenuation amount of the transponder of each wavelength is set by the second control so that the attenuation amount is determined by the detection result of the first control that is sequentially obtained. .

Furthermore, in the first control, for the transponders other than the wavelength to be measured, the conversion operation of the electric / optical converter is stopped instead of the control of the variable attenuator.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. FIG. 1 is a configuration diagram of a wavelength division multiplexing optical transmission device showing an embodiment of the present invention. In the figure, 12-1 to 12-n in each transponder are variable optical attenuators 3-1 to 3 as new elements.
A memory for storing the attenuation amount of −n, 13 on the wavelength multiplexing section side is a second optical coupler for branching the output optical signal of the wavelength multiplexing section 10, and 14 is an optical signal branched by the second optical coupler 13. The second optical power meter (detector) 15 for measuring the optical power of the variable optical attenuator 15 generates the attenuation amount control signals 5-1 to 5-n to the variable optical attenuators 3-1 to 3-n, and It is an output control unit that controls the attenuation amount of the devices 3-1 to 3-n. The other elements are the same as those corresponding to the same number in the conventional example.

Next, the operation will be described. First, the output control unit 15 in the wavelength multiplexing board 9 controls the attenuation control signal 5-
2 to 5-n, the transponder substrate 1-2 to 1-n
The first control is performed so that the amount of attenuation of the variable optical attenuators 3-2 to 3-n in the inside becomes maximum. Next, the output controller 15
Controls the attenuation of the variable optical attenuator 3-1 in the transponder board 1-1 by the attenuation control signal 5-1.
Second control is performed so that the optical power measured by the second optical power meter 14 in the wavelength multiplexing substrate 9 becomes a specified value.
At this time, since the transponder output signals 7-2 to 7-n output from the transponder boards 1-2 to 1-n are sufficiently attenuated by the variable optical attenuators 3-2 to 3-n, the wavelength multiplexing board The optical power measured by the second optical power meter 14 in 9 can be regarded as equivalent to the optical power of the wavelength λ1 from the transponder substrate 1-1. In the transponder substrate 1-1, the variable optical attenuator 3-at this time is
The attenuation amount of 1 is stored in the memory 12 in the transponder board 1-1.
Store in -1.

Thereafter, all other transponder boards 1-
The same first control is also performed for 2 to 1-n, and then the second control is performed so that the optical power of the wavelengths λ2 to λn becomes a specified value, and the variable optical attenuator 3-2 at that time The attenuation amounts of 3 to 3-n are stored in the memories 12-2 to 12-n, respectively. By performing the above operation, the optical signals of the wavelengths λ1 to λn output from the transponder boards 1-1 to 1-n are output to the second optical power meter 14 on the wavelength multiplexing board 9.
In the above, in the memory 12-, the attenuation amounts of the variable optical attenuators 3-1 to 3-n when adjusted to the specified optical power are
1 to 12-n are stored.

Next, each transponder board 1-1 to 1-
At n, the attenuation amounts stored in the memories 12-1 to 12-n are read out to control the variable optical attenuators 3-1 to 3-n, respectively. By the above operation, the transponder board 1-
All the transponder output signals 7-1 to 7-n of wavelengths λ1 to λn output from 1 to 1-n can be controlled to have a specified output power.

The memory of each transponder may be moved to the wavelength multiplexing substrate side. Alternatively, it is possible to set the attenuation amount according to the transponder having the minimum attenuation amount wavelength. FIG. 2 is a diagram showing the configuration of another wavelength division multiplexing optical transmission device according to the first embodiment. The same reference numerals as those in FIG. 1 indicate the same or corresponding portions. In the figure, 16
Is a second memory for storing the value of the optical power measured by the second optical power meter 14.

The operation of the apparatus having this structure is as follows. First, the output control unit 15 in the wavelength multiplexing board 9
The variable optical attenuators 3-2 to 3 in the transponder boards 1-2 to 1-n are controlled by the attenuation control signals 5-2 to 5-n.
The first control is performed so that the attenuation amount of n becomes maximum. Next, the output control unit 15 uses the attenuation control signal 5-1 to
Variable optical attenuator 3-1 in transponder board 1-1
The first control is also performed so that the attenuation amount of is minimized. At this time, the transponder output signals 7-2 to 7-n output from the transponder boards 1-2 to 1-n are
Since it is sufficiently attenuated by the variable optical attenuators 3-2 to 3-n, the optical power measured by the second optical power meter 14 in the wavelength multiplex substrate 9 is the light of the wavelength λ1 from the transponder substrate 1-1. It can be considered equivalent to power. Next, the measured value of the optical power measured by the second optical power meter 14 in the wavelength multiplexing board 9 is stored in the second memory 16 in the wavelength multiplexing board 9.

After that, all other transponder boards 1-
The same first control is performed for 2 to 1-n to measure the optical power of the wavelengths λ2 to λn in the wavelength multiplexing substrate 9.
The value of the optical power measured by the second optical power meter 14 at that time is stored in the second memory 16 in the wavelength multiplexing substrate 9, respectively. By performing the above operation, the wavelengths λ1 to λ output from the transponder boards 1-1 to 1-n are output.
The optical signal of n is measured by the second optical power meter 14 in the wavelength multiplex substrate 9, and the measured value of the optical power measured by the second optical power meter 14 at that time is measured by the second optical power meter 14 in the wavelength multiplex substrate 9. It is stored in the memory 16 of.

Next, the output control section 15 in the wavelength multiplexing substrate 9
Is all the measured values of the optical power of the optical signals of the wavelengths λ1 to λn output from the transponder boards 1-1 to 1-n stored in the second memory 16, and the lowest of the read values. The value is the specified value of the input optical signal of the wavelength multiplexing substrate 9. Next, the output control unit 15 causes the attenuation control signal 5-
2 to 5-n, the transponder substrate 1-2 to 1-n
The variable optical attenuators 3-2 to 3-n in the inside are controlled so that the amount of attenuation becomes maximum. Next, the output control unit 15 controls the attenuation amount of the variable optical attenuator 3-1 in the transponder substrate 1-1 by the attenuation amount control signal 5-1 and the second light in the wavelength multiplexing substrate 9 is controlled. Second control is performed so that the optical power measured by the power meter 14 becomes a specified value.

After that, all other transponder boards 1-
The same operation is performed for 2 to 1-n, and wavelengths λ2 to λ
The second control is performed so that the optical power of n becomes a specified value. By performing the above operation, the transponder board 1-1
Of optical signals of wavelengths λ1 to λn output from 1 to n, the one having the lowest input power among them is set as a specified value, and the optical signals of wavelengths λ1 to λn input to the wavelength multiplexing substrate 9 are set. The optical power of can be adjusted to a specified value.

Embodiment 2. FIG. 3 is a diagram showing the configuration of the wavelength division multiplexing optical transmission device according to the second embodiment of the present invention. The same reference numerals as those in FIGS. 1 and 2 indicate the same or corresponding portions. In the figure, 17-1 to 17-n are output stop control signals for performing optical output stop control on the electric / optical converters 2-1 to 2-n.

The operation in this configuration is as follows. First, the output control unit 15 in the wavelength multiplexing substrate 9 receives the optical output stop control signals 17-2 to 17-n, and then the electric / optical converter 2-2 in the transponder substrates 1-2 to 1-n.
Control to stop the optical output of ~ 2-n,
The output control unit 15 first controls the optical output stop control signal 17-1 so as to output the optical output of the electro-optical converter 2-1 in the transponder substrate 1-1 in a normal state. Next, the output control unit 15 causes the attenuation control signal 5-
1, the first control is also performed so that the attenuation amount of the variable optical attenuator 3-1 in the transponder substrate 1-1 is minimized. At this time, the transponder board 1-2-1
Transponder output signals 7-2 to 7 output from -n
Since -n controls the output stop for the electro-optical converters 2-2 to 2-n, the optical power measured by the second optical power meter 14 in the wavelength multiplex substrate 9 is the transponder substrate 1 It can be regarded as the optical power of the wavelength λ1 from −1. Next, the measured value of the optical power measured by the second optical power meter 14 in the wavelength multiplexing board 9 is stored in the second memory 16 in the wavelength multiplexing board 9. Next, the output controller 15
Uses the light output stop control signals 17-2 to 17-n to cancel the stop of the light output of the electric / optical converters 2-2 to 2-n in the transponder boards 1-2 to 1-n. Control.

Thereafter, all other transponder boards 1-
The same first control is performed for 2 to 1-n to measure the optical power of the wavelengths λ2 to λn in the wavelength multiplexing substrate 9.
The value of the optical power measured by the second optical power meter 14 at that time is stored in the second memory 16 in the wavelength multiplexing substrate 9, respectively. By performing the above operation, the wavelengths λ1 to λ output from the transponder boards 1-1 to 1-n are output.
The optical signal of n is measured by the second optical power meter 14 in the wavelength multiplex substrate 9, and the measured value of the optical power measured by the second optical power meter 14 at that time is measured by the second optical power meter 14 in the wavelength multiplex substrate 9. It is stored in the memory 16 of.

Next, the output control unit 15 in the wavelength multiplexing substrate 9
Is all the measured values of the optical power of the optical signals of the wavelengths λ1 to λn output from the transponder boards 1-1 to 1-n stored in the second memory 16, and the lowest of the read values. The value is the specified value of the input optical signal of the wavelength multiplexing substrate 9. Next, the output control unit 15 in the wavelength multiplexing substrate 9
According to the optical output stop control signals 17-2 to 17-n, the electric / optical converters 2 in the transponder boards 1-2 to 1-n are provided.
The output control unit 15 controls the optical output stop control signal 17-1 to stop the optical output of the -2-2 to 2-n, and the output control unit 15 controls the electro-optical converter 2-1 in the transponder substrate 1-1. The optical output of is controlled to be output in the normal state. Further, the variable optical attenuator 3 provided in the transponder substrate 1-1 is controlled by the attenuation control signal 5-1 so that the optical power measured by the second optical power meter 14 provided in the wavelength multiplexing substrate 9 becomes a specified value. The second control is performed for the attenuation amount of -1.

Thereafter, all other transponder boards 1-
The same operation is performed for 2 to 1-n, and wavelengths λ2 to λ
The second control is performed so that the optical power of n becomes a specified value. By performing the above operation, the transponder board 1-1
Of optical signals of wavelengths λ1 to λn output from 1 to n, the one having the lowest input power among them is set as a specified value, and the optical signals of wavelengths λ1 to λn input to the wavelength multiplexing substrate 9 are set. The optical power of can be adjusted to a specified value.

[0024]

As described above, according to the present invention, the wavelength multiplexing section is provided with the detector for measuring the optical power of the wavelength multiplexed optical signal and the control means for the first and second controls. Therefore, there is no need to individually branch the output optical signals of the variable optical attenuator and measure the optical power thereof, and it is possible to adjust the optical power of the signal light to be multiplexed with a simple configuration.

Further, since the electric / optical converter is turned on / off, there is an effect that the optical power of the signal light to be multiplexed can be strictly adjusted.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a level-adjusted wavelength division multiplexing optical transmission device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of another wavelength division multiplexing optical transmission device according to the first embodiment.

FIG. 3 is a configuration diagram of a level adjustment wavelength division multiplexing optical transmission device according to a second embodiment of the present invention.

FIG. 4 is a configuration diagram of a conventional wavelength division multiplexing optical transmission device.

[Explanation of symbols]

1-1 to 1-n Transponder substrate, 2-1 to 2-n
Electric / optical converter, 3-1 to 3-n variable optical attenuator, 4
-1 to 4-n First optical coupler, 5-1 to 5-n Attenuation control signal, 6-1 to 6-n Monitor signal, 7-1 to
7-n transponder output signal, 8 optical power meter (detector), 9 wavelength multiplex board, 10 wavelength multiplex section, 11
WDM signal, 12-1 to 12-n memory, 13
Second optical coupler, 14 Second optical power meter, 15
Output control unit, 16 Second memory, 17-1 to 17-
n Output stop control signal.

Claims (3)

[Claims] 1. Each transponder is provided with a variable optical attenuator corresponding to each wavelength to be wavelength-multiplexed, and the wavelength multiplexing unit is configured to multiplex optical signals from each of the transponders. In the section, a detector for detecting the optical output after multiplexing, and the attenuation amount of the attenuator of each transponder are sequentially controlled to a first predetermined value, and the first control is then performed. A level adjusting wavelength division multiplexing optical transmission device comprising: an output control unit that performs a second control for setting the attenuation amount of each transponder based on the detection amount of the detector when controlled to a value. 2. The output control unit, as the first predetermined value,
The transponders of the wavelengths to be measured are controlled so as to have the minimum attenuation, and at the same time, the transponders of the other wavelengths are sequentially controlled so as to have the maximum attenuation. 2. The level-adjusting WDM optical transmission device according to claim 1, wherein the variable attenuation amount of the transponder of each wavelength is set by the second control so that the attenuation amount is determined by the detection result of the control of. . 3. In the first control, the conversion operation of the electric / optical converter is stopped in place of the control of the variable attenuator for the transponder other than the wavelength to be measured. The level-adjusting wavelength division multiplexing optical transmission device according to claim 1 or 2.