JP2010074678A - Optical transmission system and optical transmission network system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To individually set transmission line input light power to each channel in an optical transmission system. <P>SOLUTION: The optical transmission system composes an optical transmission network. The optical transmission system includes: a wavelength selection switch; a means of amplifying many kinds of optical levels including a first optical amplification means connected to a first output port of the wavelength selection switch and a second one connected to a second output port of the wavelength selection switch; and a wavelength multiplexing means for wavelength-multiplexing signal light output from the first optical amplification means and that output from the second optical amplification means to transmit the wavelength-multiplexed signal light to the optical transmission line of the optical transmission network. The first optical amplification means amplifies each of one or not less than two pieces of signal light of a plurality of wavelengths output from the first output port to a first optical level. The second optical amplification means amplifies each of one or not less than two pieces of signal light having a plurality of wavelengths output from the second output port to a second optical level higher than the first one. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for transmitting signal light at an appropriate transmission optical power for each path in each node of an optical transmission network.

  As the demand for data communication increases, optical transmission networks using wavelength division multiplexing technology capable of transmitting large volumes of traffic are becoming widespread. In such an optical transmission network, an optical cross-connect device (OXC: Optical cross Connect) that switches the path (signal light of a specific wavelength) as an optical transmission device, branches a path from a ring network, An optical add / drop multiplexer to be inserted or an inter-ring connecting device for connecting rings is used.

For example, a metro network that accommodates access traffic, forwards traffic within a city, and bridges between core networks constitutes a ring network and is connected to each other as shown in FIG. It is common to take Further, in an optical transmission device (each node in FIG. 1) in an optical transmission network, it is desired to deliver an optical signal as much as possible from the viewpoint of economically constructing the network.
E. Bert Basch, et.al, "Architectural Tradeoffs for Reconfigurable Dense Wavelength-Division Multiplexing Systems", IEEE journal of selected topics in quantum electronics, VOL.12, NO.4, JULY / AUGUST. 2006

  FIG. 1 shows a path A set in the ring 1 and a path B set across the ring 1 and the ring 2 as an example. As exemplified by the path A and the path B, in the optical transmission network such as the ring network, various long and short paths are set, and the variation in the transmission distance for each path is large. Therefore, a short transmission distance path and a long transmission distance path are mixed in all paths accommodated by a certain optical transmission apparatus.

  Now, in the optical transmission network, the optical signal-to-noise ratio (OSNR) decreases in proportion to the transmission distance of the path. Therefore, the optical transmission apparatus constituting the optical transmission network is improved in order to improve the OSNR on the terminating side of the path. In general, an optical signal transmission path input optical power (transmission optical power) is increased. Conventionally, regardless of the length of the path, for example, the same transmission line input optical power is set in all paths according to the long path, and an optical signal is output.

  That is, if the transmission distance of the path is short, the optical signal power may be lower than when the transmission distance of the path is long, but the transmission path input optical power is set uniformly. For this reason, there is a uselessly high-power path, and the total input optical power of all the paths becomes higher than necessary. As a result, the conventional technique has a problem that nonlinear distortion increases. Further, when the transmission path input optical power is lowered in order to suppress nonlinear distortion, the optical signal-to-noise ratio (OSNR) of a path having a long transmission distance increases. Hereinafter, “path” is referred to as “channel” in each optical transmission apparatus.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a technique for setting transmission line input optical power for each channel in an optical transmission apparatus in an optical transmission network.

  In order to solve the above-described problems, the present invention provides an optical transmission device for configuring an optical transmission network, an input port for receiving signal light from an optical transmission line of the optical transmission network, and two or more input ports A wavelength selective switch comprising: a plurality of output ports; and a function of outputting signal light of a wavelength arbitrarily selected from a plurality of wavelengths included in the signal light from an arbitrary output port; and a first of the wavelength selective switches A plurality of optical level amplifying means including a first optical amplifying means connected to the output port and a second optical amplifying means connected to the second output port of the wavelength selective switch; and the first light. Wavelength multiplexing means for wavelength-multiplexing the signal light output from the amplification means and the signal light output from the second optical amplification means, and sending the wavelength-multiplexed signal light to the optical transmission line of the optical transmission network; , Be prepared The first optical amplifying means amplifies each of the signal light having one or more wavelengths output from the first output port to a first optical level, and the second optical amplifying means An optical transmission device characterized by amplifying each of one or more signal lights having a plurality of wavelengths output from a second output port to a second optical level higher than the first optical level. Composed.

  In the optical transmission apparatus, a first spectrum shaper for adjusting an optical level for each wavelength is provided in a preceding stage or a subsequent stage of the first optical amplifying means, and in a preceding stage or a subsequent stage of the second optical amplifying means. It is good also as providing the 2nd spectrum shaper for adjusting the light level for every wavelength.

  The present invention is also an optical transmission apparatus for configuring an optical transmission network, an input port for receiving signal light from an optical transmission line of a first optical transmission network, and optical transmission of a second optical transmission network. Two or more input ports including an input port for receiving signal light from the path, and two or more output ports, each having a wavelength arbitrarily selected from the plurality of wavelengths included in each signal light A wavelength selective switch having a function of outputting signal light from an arbitrary output port; a first optical amplifying unit connected to the first output port of the wavelength selective switch; and a second output of the wavelength selective switch. A plurality of optical level amplifying means including a second optical amplifying means connected to the port; signal light output from the first optical amplifying means; and signal light output from the second optical amplifying means. Receive and these Of the wavelengths included in the signal light, the signal light of the wavelength to be transmitted to the optical transmission line of the first optical transmission network is wavelength-multiplexed and transmitted to the optical transmission line of the first optical transmission network, and the first Wavelength multiplexing means for wavelength-multiplexing signal light having a wavelength to be transmitted to the optical transmission line of the second optical transmission network and transmitting the signal light to the optical transmission line of the second optical transmission network, and the first optical amplification The means amplifies each of the one or more signal lights having a plurality of wavelengths output from the first output port to a first optical level, and the second optical amplifying means includes the second optical amplifying means. Each of the signal lights having one or more wavelengths output from the output port may be amplified to a second optical level higher than the first optical level, and the optical transmission apparatus may be configured.

  In the optical transmission apparatus, a first spectrum shaper for adjusting an optical level for each wavelength is provided in a preceding stage or a subsequent stage of the first optical amplifying means, and in a preceding stage or a subsequent stage of the second optical amplifying means. It is good also as providing the 2nd spectrum shaper for adjusting the light level for every wavelength.

  The optical transmission device is, for example, an optical cross-connect device, an inter-ring connection device, or an optical add / drop multiplexer. It is also possible to provide an optical transmission network system in which a plurality of the optical transmission apparatuses are prepared and these optical transmission apparatuses are connected via an optical transmission path.

  ADVANTAGE OF THE INVENTION According to this invention, the optical transmission apparatus which can set transmission-line input optical power can be provided separately for the channel from which transmission distance differs, By using this optical transmission apparatus, the receiving side optical signal pair of each path | pass can be provided. It is possible to construct an optical transmission network with a nonlinear penalty as small as possible while improving the noise ratio.

  Further, since the optical amplifying means itself has nonlinearity, in the conventional configuration, nonlinear waveform deterioration such as four-wave mixing inside the optical amplifying means has been a problem. For example, the size of the four-wave mixed light is determined by the optical power level of the adjacent surrounding channels. If the optical power of the target channel is small, the relative crosstalk amount increases accordingly. Therefore, if optical amplification is performed with different levels mixed, nonlinear waveform distortion increases in a channel with a low optical power level. Therefore, as in the present invention, by separating the optical amplifying means according to the set light level, there is an effect that the optical level difference in the optical amplifying means is reduced and nonlinear crosstalk is reduced.

  Embodiments of the present invention will be described below with reference to the drawings. In the present specification, the same reference numerals are assigned to components having the same functions.

(First embodiment)
FIG. 2 shows a configuration diagram of the optical transmission apparatus 30 according to the first embodiment of the present invention. As shown in FIG. 2, the optical transmission device 30 includes an optical switch function unit 10 and an optical amplifying unit 20 for each channel. The optical transmission device 30 includes an inter-ring connecting device that connects ring networks, an optical cross-connect device in a mesh network, and optical add / drop multiplexing that performs insertion / dropping (add / drop) of signal light between a client network and a ring network. It can be applied to any of the devices.

  As shown in FIG. 2, the optical switch function unit 10 includes signal light (one or a plurality of wavelengths multiplexed, and so on) from T (T is an integer of 1 or more) optical transmission lines (optical fibers). , Select each wavelength (channel) in each signal light as appropriate, perform path conversion (cross connect), add / drop (add / drop), and output signal light to each of the T optical transmission lines It is a functional part to do.

  In order to realize such a function, the optical switch function unit 10 includes a wavelength demultiplexing unit 11, a cross connect / insertion / branching unit 12, and a wavelength multiplexing unit 13. The cross-connect / insertion / branching unit 12 may be a functional unit that performs either one of the cross-connect or the insertion / branch, or may be a functional unit that performs both.

  FIG. 3 shows a functional configuration diagram of the optical amplifying unit 20 for each channel. In the configuration of FIG. 2, there are a plurality of optical amplifying units for each channel, but these are basically the same configuration (however, the specific number of optical amplification levels and their values are determined for each individual channel optical amplifying unit. It may differ depending on the amplification section).

As shown in FIG. 3, the optical amplifying unit 20 for each channel includes a 1 × N (1 input N output, N is an integer of 2 or more) wavelength selective switch (WSS) 21 and a high output level L _H. Optical amplification unit 22, low output level L _L optical amplification unit 23, and wavelength multiplexing unit 24.

The 1 × N wavelength selective switch 21 has a function of inputting signal light from an input port and outputting signal light of an arbitrary wavelength from an arbitrary output port among the N output ports. Note that “arbitrary” means that it can be appropriately set by remote control or the like. In the present embodiment, the 1 × N wavelength selective switch 21 outputs a signal light obtained by multiplexing a predetermined wavelength to be output at the output level L _H among a plurality of wavelengths multiplexed with the input signal light. The signal light that is output from the output port to which the optical amplifying unit 22 is connected and is multiplexed with a predetermined wavelength to be output at the output level L _L out of the plurality of wavelengths multiplexed in the input signal light. Output from the output port to which the optical amplifier 23 is connected.

As the 1 × N wavelength selective switch 21, a configuration including a wavelength separation unit, a wavelength selection unit, and a wavelength multiplexing unit is known. This wavelength separation unit is constituted by, for example, MEMS, liquid crystal, or the like, and can directly monitor the power for each wavelength by tapping by optical branching or the like. By using this function, the power monitor value is compared with a predetermined value, and the output level L _H or the output level L _L is selected according to the magnitude relationship. It may be.

The optical amplification unit 22 for the high output level L _H is a functional unit that amplifies the signal light of each wavelength included in the input signal light to the same level L _H and outputs it. The optical amplifier 23 for the low output level L _L is a functional unit that amplifies the signal light of each wavelength included in the input signal light to the same level L _L and outputs the amplified signal light. The state of this optical amplification is shown in FIG.

  The wavelength multiplexing unit 24 is a functional unit that multiplexes and outputs (inputs to the transmission line) the input signal light that is amplified by the optical amplification units 22 and 23. For example, an optical coupler, an N × 1 wavelength selective switch, or the like It is.

In the optical transmission device 30 shown in FIG. 2, the optical switch function unit 10 appropriately performs wavelength separation, path conversion, and wavelength multiplexing on the signal light input from each optical transmission path. The output signal light is input to the optical amplifying unit 20 for each channel. In the optical amplifying unit 20 for each channel, the signal light having a wavelength that requires output at a high level L _H based on a preset setting is output from the optical amplifying unit 22. Level amplification is performed, and signal light having a wavelength that requires output at a low level L _L is subjected to level amplification by the optical amplifying unit 23, and these are wavelength-multiplexed and transmitted to the optical transmission line.

  For example, consider a case where the present optical transmission device 30 is used as a node C in the ring 1 shown in FIG. In this case, the optical transmission device 30 is used as an optical add / drop device, and T in the optical transmission device is 1. That is, the optical transmission device 30 receives the signal light in the counterclockwise direction of the ring 1 in FIG. 1 and outputs the signal light in which the add light is inserted in the counterclockwise direction of the ring 1. .

In the optical amplifying unit 20 for each channel of the optical transmission device 30, the signal light of the path having a relatively short transmission distance including the path A is output by the 1 × N wavelength selective switch 21 for the low output level L _L. is output to the 22, the level of the optical amplification is performed, the signal light of the transmission distance is relatively long path including the path B is, is output to the optical amplifier 23 for high output level L _H, the level of light Amplification is made. These signal lights are wavelength-multiplexed by the wavelength multiplexing unit 24 and output.

In the above example, although the type of amplification level in the channel for each optical amplifier unit 20 has two types of L _H and L _L, the optical amplification portion of the number corresponding to a number of different levels from two 1 × Needless to say, it may be provided between the N wavelength selective switch 21 and the wavelength multiplexing unit 24.

  FIG. 4 shows another configuration example of the optical amplifying unit 20 for each channel. As shown in FIG. 4, the optical amplifying unit 20 for each channel includes spectrum shapers 101 and 104 subsequent to the optical amplifying units 22 and 23. In addition, a part of the light output from the spectrum shaper 101 is tapped to monitor the optical power of each channel, and control for performing feedback control so that the optical level of each channel becomes a target value A circuit 103 is provided. Similarly, a monitor unit 105 and a control circuit 106 are provided for the spectrum shaper 104. Note that a part of the light after wavelength multiplexing may be tapped and the tapped light may be provided to the monitor units 102 and 105.

  As shown in FIG. 4, it is possible to adjust the optical level of each channel of the light transmitted to the optical fiber with high accuracy by installing the spectrum shapers 101 and 104 in the subsequent stage of the optical amplifying units 22 and 23. Become. In general, an optical amplifier has a gain wavelength dependency, and a gain equalizer is incorporated to compensate for it. However, the accuracy is limited, and gain deviation due to this wavelength is amplified when it passes through a plurality of optical amplifiers in multiple stages. Moreover, it cannot respond to time changes.

  Therefore, in this example, in order to absorb the wavelength dependency of the optical power due to the gain deviation, the spectral shapers 101 and 104 that can be dynamically controlled are inserted after the optical amplification units 22 and 23. In addition, monitor units 102 and 105 that monitor the optical power of each channel and control circuits 103 and 106 that perform feedback control so that the optical level of each channel becomes a target value are provided. It becomes possible to control the power.

  Since the monitor units 102 and 105 need to monitor the optical power for each channel, they have a function of measuring the optical power of each wavelength after wavelength separation. Further, the control circuits 103 and 106 compare the measured value of the level of each channel with a preset target value, and reduce the difference between the channels of the spectrum shapers 101 and 104, or Adjust the wavelength loss value.

  As the spectrum shaper used in this example, the input light is wavelength-separated for each channel, and the light of each wavelength is input to an optical variable attenuator provided for each wavelength. Alternatively, there is a configuration in which wavelength-multiplexed signal light is spatially separated using a wavelength dispersion medium, wavelength-dependent attenuation is given using a spatial modulator, and wavelength synthesis is performed again.

  Further, in FIG. 4, the spectrum shapers 101 and 104 are provided in the subsequent stage of the optical amplifying units 22 and 23, but the same applies even if the spectrum shapers 101 and 104 are disposed in the previous stage of the optical amplifiers 22 and 23. An effect is obtained.

  In the optical transmission device 30 according to the present embodiment, since it is possible to perform optical amplification by changing the output level for each channel, the output level of the signal light of the long path is made larger than the output level of the signal light of the short path. You can set the output level. Therefore, it is not necessary to set the entire output level to be the same for a long path as in the prior art, and an optical transmission network is constructed in which the nonlinear penalty is minimized while improving the terminating optical signal-to-noise ratio of each path. It becomes possible.

  In addition, since the optical amplification unit itself has nonlinearity, in the conventional configuration, nonlinear waveform deterioration such as four-wave mixing inside the optical amplification unit has been a problem. For example, the size of the four-wave mixed light is determined by the optical power level of the adjacent surrounding channels. If the optical power of the target channel is small, the relative crosstalk amount increases accordingly. Therefore, if optical amplification is performed with different levels mixed, nonlinear waveform distortion increases in a channel with a low optical power level. Therefore, as in the present embodiment, by separating the optical amplifying unit according to the set light level, the optical level difference in the optical amplifying unit is reduced, and there is an effect of reducing nonlinear crosstalk.

(Second Embodiment)
FIG. 5 shows a configuration diagram of an optical transmission device 40 according to the second embodiment of the present invention. This optical transmission device 40 is used as an inter-network connection device between the network 1 and the network 2 or an optical cross-connect device.

As shown in FIG. 5, the optical transmission device 40 includes an N × M (N input M output, N, M is an integer of 2 or more) wavelength selection switch 41, and an M × N (M input N output) wavelength. And an optical amplifier 42 for a high output level L _H and an optical amplifier 43 for a low output level L _L between the N × M wavelength selective switch 41 and the M × N wavelength selective switch 44. It has the composition provided. The functions of these optical amplifying units are the same as those of the optical amplifying units 22 and 23 in each channel optical amplifying unit 20 in the first embodiment.

  Each of the N × M wavelength selective switch 41 and the M × N wavelength selective switch 44 inputs an arbitrary wavelength (one or more) from an arbitrary input port, and outputs an arbitrary wavelength (one or more) from an arbitrary output port. This is a wavelength selective switch having the function of Further, the M × N wavelength selective switch 44 corresponds to the one in which the input and output of the N × M wavelength selective switch 41 are reversed.

  In the configuration of FIG. 5, the input port of the N × M wavelength selective switch 41 and the output port of the M × N wavelength selective switch 44 are connected to the network 1 and the network 2, respectively. The output ports are connected to the optical amplifying unit 42 and the optical amplifying unit 43, and these are connected to the two input ports of the M × N wavelength selective switch 44.

  Next, an operation example of the optical transmission device 40 illustrated in FIG. 5 will be described.

Signal light is input from the network 1 to the input port of the N × M wavelength selective switch 41, and signal light is input from the network 2 to another input port of the N × M wavelength selective switch 41. The N × M wavelength selective switch 41 is a signal light having a wavelength to be output at a high output level L _H among the wavelengths of both signal lights (generally, signal light straddling between networks, network not straddling between networks). (Including signal light on 1 and signal light on network 2 that does not cross between networks) is output from the output port to which the optical amplifying unit 42 is connected, and has a wavelength to be output at a low output level L _L An optical amplifying unit 43 is connected to signal light (in general, including signal light straddling between networks, signal light on network 1 not straddling between networks, and signal light on network 2 straddling between networks). Output from the output port.

  Then, in each of the optical amplifying units 42 and 43, optical amplification of each wavelength is performed, and the optically amplified signal light is output from each of the optical amplifying units 42 and 43, and the input port of the corresponding M × N wavelength selective switch 44 Is input.

  Then, the M × N wavelength selection switch 44 outputs the signal light multiplexed with the wavelength to be transmitted to the network 1 among the wavelengths of the signal light input to each input port, and should be transmitted to the network 2. The signal light multiplexed in wavelength is output to the network 2.

  FIG. 6 shows another configuration example of the optical transmission device 40. As shown in FIG. 6, the optical transmission device 40 includes spectrum shapers 111 and 114 at the subsequent stage of the optical amplification units 42 and 43. In addition, a part of the light output from the spectrum shaper 111 is tapped to monitor the optical power of each channel 112, and control for performing feedback control so that the optical level of each channel becomes a target value A circuit 113 is provided. Similarly, a monitor unit 115 and a control circuit 116 are provided for the spectrum shaper 114. Note that a part of the light after wavelength multiplexing may be tapped and the tapped light may be provided to the monitor units 112 and 115.

  As shown in FIG. 6, it is possible to adjust the light level of each channel of the light transmitted to the optical fiber with high accuracy by installing the spectrum shapers 111 and 114 in the subsequent stage of the optical amplifying units 42 and 43. Become. In general, an optical amplifier has a gain wavelength dependency, and a gain equalizer is incorporated to compensate for it. However, the accuracy is limited, and gain deviation due to this wavelength is amplified when it passes through a plurality of optical amplifiers in multiple stages. Moreover, it cannot respond to time changes.

  Therefore, in this example, in order to absorb the wavelength dependence of the optical power due to the gain deviation, spectrum shapers 111 and 114 that can be dynamically controlled are inserted after the optical amplifying units 42 and 43, respectively. In addition, the monitor units 112 and 115 that monitor the optical power of each channel and the control circuits 113 and 116 that perform feedback control so that the optical level of each channel becomes a target value are provided. It becomes possible to control the power.

  Since the monitor units 112 and 115 need to monitor the optical power for each channel, they have a function of measuring the optical power of each wavelength after wavelength separation. In addition, the control circuits 113 and 116 compare the measured values of the levels of the respective channels with preset target values, and reduce the difference between the channels of the spectrum shapers 111 and 114, or Adjust the wavelength loss value.

  As the spectrum shaper used in this example, the input light is wavelength-separated for each channel, and the light of each wavelength is input to an optical variable attenuator provided for each wavelength. Alternatively, there is a configuration in which wavelength-multiplexed signal light is spatially separated using a wavelength dispersion medium, wavelength-dependent attenuation is given using a spatial modulator, and wavelength synthesis is performed again.

  In FIG. 6, the spectrum shapers 111 and 114 are provided in the subsequent stage of the optical amplifying units 42 and 43. An effect is obtained.

  Also in the configuration shown in the present embodiment, the output level corresponding to the transmission distance of the path can be appropriately set for each channel in consideration of the nonlinear penalty. In addition, the configuration shown in this embodiment also has an advantage that the optical amplification unit can be shared between networks.

(Third embodiment)
Next, a third embodiment of the present invention will be described. FIG. 7 shows a configuration diagram of an optical transmission device 50 according to the third embodiment. The optical transmission device 50 is an optical add / drop multiplexer (ROADM) including the optical amplifying unit 20 for each channel in the first embodiment.

  As shown in FIG. 7, the optical transmission device 50 includes an optical coupler 51, a 1 × N wavelength selective switch 52, an N × 1 wavelength selective switch 53, and an optical amplifying unit 20 for each channel. In the optical transmission device 50 shown in FIG. 7, the input signal light is branched by an optical coupler 51, and one of the branched signal lights is input to a 1 × N wavelength selection switch 52 and 1 × N wavelength selection is performed. In the switch 52, signal light having a specific wavelength is dropped as drop signal light. The other signal light branched by the optical coupler 51 is input to the N × 1 wavelength selective switch 53, and the signal light having the dropped wavelength is blocked and another signal light is inserted from the client network side, and these are multiplexed. The signal light thus output is output and input to the optical amplifying unit 20 for each channel.

The channel-by-channel optical amplification unit 20 has the same configuration as the channel-by-channel optical amplification unit in the first embodiment. The 1 × N wavelength selective switch 21 in the optical amplifying unit 20 for each channel is a signal obtained by multiplexing a predetermined wavelength to be output at the output level L _H among a plurality of wavelengths multiplexed in the input signal light. The light is output from the output port to which the optical amplifying unit 22 is connected, and among a plurality of wavelengths multiplexed in the input signal light, a wavelength that is determined in advance to be output at the output level L _L is multiplexed. The signal light is output from the output port to which the optical amplifying unit 23 is connected. The optical amplification units 22 and 23 amplify the optical level, and the wavelength multiplexing unit 24 multiplexes and outputs the amplified signal lights.

  As shown in FIG. 8, similarly to the configuration shown in FIG. 4 in the first embodiment, the configuration may include spectrum shapers 121 and 124, monitor units 122 and 125, and control circuits 123 and 126.

(Example of channel output level design method)
Next, an example of a method for designing the output level of each path (channel) accommodated in each optical transmission device in the optical transmission network including the optical transmission device according to the present invention will be described.

  As shown in FIG. 9, a network control device 61 is provided for controlling an optical transmission network system 60 constituted by each node which is an optical transmission device according to the present invention, and each node and the network control device 61 are connected to a network ( For example, it is connected via an IP network other than the optical transmission network to be controlled.

  As illustrated in FIG. 9, the network control device 61 includes an instruction information input unit 62, a calculation unit 63, a level diagram storage unit 64, an information conversion unit 65, and a control information output unit 66. As shown in FIG. 10, the level diagram storage unit 64 stores a level diagram (transmission path input optical power of the optical transmission apparatus) for each channel and for each span between nodes. The level diagram storage unit 64 may store the incoming OSNR of each channel (path) and various transmission penalties. The operation of the network control device 61 is as follows.

  The instruction information input unit 62 receives an optical path setting request including a start point and an end point. Based on the information stored in the level diagram storage unit 64, the calculation unit 63 calculates the incoming OSNR in the optical path to be set and the nonlinear penalty of the optical transmission path, thereby setting the optical path to be set. The output level in each span is determined. In other words, the calculation unit 63 secures the incoming OSNR necessary for signal light transmission in the optical path to be set based on the information stored in the level diagram storage unit 64, and includes all the optical paths that have already been set. The output level in each span of the optical path to be set is determined so that the non-linear penalty in the optical path falls within a predetermined allowable value range.

For example, in the information stored in the bell diagram storage unit 64 shown in FIG. 10, it is assumed that channels other than channel N (Ch-N) are already set channels (paths), and that Ch-N is a setting target path. . In this case, for example, since the Ch-N path to be set has a long transmission distance, the calculation unit 63 temporarily sets each span to the high output level L _H in order to set the incoming OSNR to an appropriate value. The non-linear penalty is calculated based on the total optical power of each channel in each span, and if the allowable value is exceeded, the Ch-N output level at the corresponding node is lowered (L _L ) (in the example of FIG. 10). , Span 2-3, 3-4). In this way, the calculation unit 63 determines the output level for each span of the path to be set, and stores it in the level diagram storage unit 64.

  The information conversion unit 65 calculates the information calculated by the calculation unit 63 and stored in the level diagram storage unit 64 as node control information for controlling the node (the output port of the corresponding channel in the WSS of each node, each light The control information output unit 66 transmits the node control information to each node on the path. Thereby, the setting in the wavelength selective switch 21, the optical amplifying units 21, 22 and the like is made in each node, and the optical amplification operation corresponding to each path as described above becomes possible.

  The present invention is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the claims. For example, in the above-described embodiment, a configuration in which the channel-by-channel optical amplifying unit is disposed at a position to amplify the signal light after the path conversion or the like is performed (the first embodiment or the like), or the channel-by-channel optical amplification. Although the configuration for optical level amplification corresponding to the unit is arranged between the wavelength conversion switches that perform path conversion or the like, the position where the optical amplification unit for each channel is arranged is limited to the above position It can be arranged in various positions other than the above.

It is a figure which shows the example of a ring network. It is a block diagram of the optical transmission apparatus 30 in 1st Embodiment. FIG. 3 is a configuration diagram of a channel-by-channel optical amplification unit 20. FIG. 6 is a configuration diagram of another example of the channel-by-channel optical amplification unit 20. It is a block diagram of the optical transmission apparatus 40 in 2nd Embodiment. It is a block diagram of the other example of the optical transmission apparatus 40 in 2nd Embodiment. It is a block diagram of the optical transmission apparatus 50 in 3rd Embodiment. It is a block diagram of the other example of the optical transmission apparatus 50 in 3rd Embodiment. It is a figure for demonstrating the example of the design method of the output level of each channel. It is a figure which shows the example of the information memorize | stored in the level diagram memory | storage part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical switch functional part 11 Wavelength demultiplexing part 12 Cross-connect / insertion / branching part 13 Wavelength multiplexing part 20 Channel optical amplification part 21 1 × N wavelength selective switch 22, 23 Optical amplification part 24 Wavelength multiplexing part 30, 40, 50 Optical transmission Device 41 N × M wavelength selective switch 44 M × N wavelength selective switch 51 Optical coupler 52 1 × N wavelength selective switch 53 N × 1 wavelength selective switch 61 Network control device 62 Instruction information input unit 63 Calculation unit 64 Level diagram storage unit 65 Information converter 66 Control information output unit 101, 104, 111, 114, 121, 124 Spectrum shaper 102, 105, 112, 115, 122, 125 Monitor unit 103, 106, 113, 116, 123, 126 Control circuit

Claims (6)

An optical transmission device for configuring an optical transmission network,
An input port for receiving signal light from an optical transmission line of the optical transmission network and two or more output ports are provided, and signal light of a wavelength arbitrarily selected from a plurality of wavelengths included in the signal light is arbitrarily selected Wavelength selective switch with the function of outputting from the output port of
Multiple optical level amplification means including first optical amplification means connected to the first output port of the wavelength selective switch, and second optical amplification means connected to the second output port of the wavelength selective switch When,
The signal light output from the first optical amplifying unit and the signal light output from the second optical amplifying unit are wavelength-multiplexed, and the wavelength-multiplexed signal light is transmitted to the optical transmission line of the optical transmission network. Wavelength multiplexing means for performing,
The first optical amplifying unit amplifies each of one or more signal lights having a plurality of wavelengths output from the first output port to a first optical level, and the second optical amplifying unit. Amplifies each of the one or more wavelength signal lights output from the second output port to a second optical level higher than the first optical level.   The first spectral shaper for adjusting the light level for each wavelength is provided in the front stage or the rear stage of the first optical amplification means, and the optical level for each wavelength is provided in the front stage or the rear stage of the second optical amplification means. The optical transmission apparatus according to claim 1, further comprising a second spectrum shaper for adjusting the frequency. An optical transmission device for configuring an optical transmission network,
Two or more input ports including an input port for receiving signal light from the optical transmission line of the first optical transmission network and an input port for receiving signal light from the optical transmission line of the second optical transmission network; A wavelength selective switch including a plurality of output ports of two or more, and a function of outputting signal light of a wavelength arbitrarily selected from a plurality of wavelengths included in each signal light from an arbitrary output port;
Multiple optical level amplification means including first optical amplification means connected to the first output port of the wavelength selective switch, and second optical amplification means connected to the second output port of the wavelength selective switch When,
Receiving the signal light output from the first optical amplifying means and the signal light output from the second optical amplifying means, and out of the wavelengths included in the signal light, the first optical transmission network Wavelength-multiplexed signal light having a wavelength to be transmitted to the first optical transmission network is transmitted to the optical transmission path of the first optical transmission network, and the wavelength signal to be transmitted to the optical transmission path of the second optical transmission network Wavelength multiplexing means for wavelength-multiplexing light and sending it to the optical transmission line of the second optical transmission network,
The first optical amplifying unit amplifies each of one or more signal lights having a plurality of wavelengths output from the first output port to a first optical level, and the second optical amplifying unit. Amplifies each of the one or more wavelength signal lights output from the second output port to a second optical level higher than the first optical level.   The first spectral shaper for adjusting the light level for each wavelength is provided in the front stage or the rear stage of the first optical amplification means, and the optical level for each wavelength is provided in the front stage or the rear stage of the second optical amplification means. The optical transmission apparatus according to claim 3, further comprising a second spectrum shaper for adjusting the frequency.   5. The optical transmission device according to claim 1, wherein the optical transmission device is an optical cross-connect device, an inter-ring connection device, or an optical add / drop multiplexer.   6. An optical transmission network system in which a plurality of the optical transmission devices according to claim 1 are prepared and these optical transmission devices are connected via an optical transmission path.

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