WO2013179604A1 - Optical transmission device, optical transmission system, and optical transmission method - Google Patents

Optical transmission device, optical transmission system, and optical transmission method Download PDF

Info

Publication number
WO2013179604A1
WO2013179604A1 PCT/JP2013/003178 JP2013003178W WO2013179604A1 WO 2013179604 A1 WO2013179604 A1 WO 2013179604A1 JP 2013003178 W JP2013003178 W JP 2013003178W WO 2013179604 A1 WO2013179604 A1 WO 2013179604A1
Authority
WO
WIPO (PCT)
Prior art keywords
optical transmission
light intensity
optical
signal quality
input
Prior art date
Application number
PCT/JP2013/003178
Other languages
French (fr)
Japanese (ja)
Inventor
学 有川
タヤンディエ ドゥ ガボリ エマニュエル ル
俊治 伊東
Original Assignee
日本電気株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日本電気株式会社 filed Critical 日本電気株式会社
Publication of WO2013179604A1 publication Critical patent/WO2013179604A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/25—Arrangements specific to fibre transmission
    • H04B10/2581—Multimode transmission
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/50—Transmitters
    • H04B10/564—Power control

Definitions

  • the present invention relates to an optical transmission device, an optical transmission system, and an optical transmission method, and more particularly to an optical transmission device, an optical transmission system, and an optical transmission method when a plurality of optical transmission paths such as a multi-core fiber are used.
  • Non-Patent Document 1 In optical transmission using a multi-core fiber, it is possible to increase the transmission capacity per fiber by multiplexing signals on a plurality of cores of the multi-core fiber.
  • FIG. 8 illustrates an exemplary cross-sectional configuration of a related multicore fiber 600.
  • the seven individual cores 610 are arranged in the cladding 620 in a hexagonal configuration. That is, six cores are arranged at the positions of the apexes of the hexagon, and one core is arranged at the center of the hexagon.
  • tapered multicore connectors are used to connect single-mode multicore fibers and optical devices.
  • a multiplexing device and a demultiplexing device corresponding to the wavelength division multiplexing (WDM) system are used as the optical device.
  • WDM wavelength division multiplexing
  • Tapered multi-core connectors include multiple optical fibers and are grouped together in a tapered coupler body.
  • the tapered multicore connector has an outer diameter that matches the outer diameter of the end face of the multicore fiber.
  • the end face of the tapered multicore connector has a core configuration that matches the core configuration of the multicore fiber with respect to the core diameter, core pitch, mode field size, mode field shape, and the like.
  • the end face of the tapered coupler body is directly connected to the end face of the multicore fiber with the core of the coupler aligned with the core of each multicore fiber.
  • Each optical fiber is connected to a wavelength division multiplexing device or a polarization division multiplexing device.
  • JP 2011-193459 A paragraphs “0041” to “0053”, FIG. 7 and FIG. 8)
  • optical transmission in a multi-core fiber is a multiple-input multiple-output (MIMO) system, and a method of compensating by a signal processing technique has been studied.
  • MIMO multiple-input multiple-output
  • the configuration shown in FIG. 8 will be described as an example of the arrangement of the cores.
  • the number of cores adjacent to the core positioned at the center is six, whereas the number of cores adjacent to the core positioned at the outer periphery is three. It is a piece.
  • the number of adjacent cores differs depending on the core.
  • the crosstalk generated between the cores the crosstalk between adjacent cores is larger than the crosstalk between non-adjacent cores. Therefore, due to the difference in the number of adjacent cores, a characteristic difference occurs between optical signals transmitted through the cores.
  • each core is arranged depending on the arrangement of the cores transmitting optical signals.
  • the signal quality of the received signal after transmitting is not uniform.
  • An object of the present invention is to provide an optical transmission apparatus and an optical transmission system that solve the above-described problem that it is difficult to optimize the characteristics of an optical transmission system in an optical transmission system using a multi-core fiber. And providing an optical transmission method.
  • the optical transmission device of the present invention controls a light intensity of an input optical signal that is input to each of a plurality of optical transmission paths, sets a predetermined input light intensity, and sets the input light intensity to a plurality of lights.
  • a light intensity control unit that determines each transmission path and controls a plurality of light intensity setting units based on the determined input light intensity, and the light intensity control unit passes through each of the plurality of optical transmission paths.
  • the input light intensity for at least one of the plurality of optical transmission lines is determined based on the information relating to the signal quality of each optical signal.
  • the optical intensity of the input optical signal input to each of the plurality of optical transmission paths is controlled to be set to a predetermined input optical intensity, and each optical signal after passing through the plurality of optical transmission paths, respectively.
  • the information on the signal quality of the optical signal is acquired, the input light intensity for at least one of the plurality of optical transmission lines is determined based on the information on the signal quality, and the light of the input optical signal is determined based on the determined input light intensity. Control strength.
  • the characteristics of the optical transmission system can be optimized in the optical transmission system using the multi-core fiber.
  • FIG. 1 is a block diagram illustrating a configuration of an optical transmission apparatus according to a first embodiment of the present invention. It is a block diagram which shows the structure of the optical transmission apparatus which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the optical transmission system which concerns on the 2nd Embodiment of this invention. It is a flowchart for demonstrating the method in which the light intensity control part of the optical transmission apparatus which concerns on the 2nd Embodiment of this invention determines input light intensity. It is a figure which shows the result of having performed the processing flow which determines input light intensity in the optical transmission apparatus which concerns on the 2nd Embodiment of this invention.
  • FIG. 1 is a block diagram showing a configuration of an optical transmission apparatus 100 according to the first embodiment of the present invention.
  • the optical transmission device 100 includes a plurality of light intensity setting units 110 and a light intensity control unit 120 that controls each light intensity setting unit 110.
  • the light intensity setting unit 110 controls the light intensity of the input optical signal 10 that is input to each of the plurality of optical transmission lines 50, and sets it to a predetermined input light intensity.
  • the light intensity control unit 120 determines the input light intensity for each of the plurality of optical transmission paths 50, and controls the plurality of light intensity setting units 110 based on the determined input light intensity. At this time, the input light intensity for at least one of the plurality of optical transmission paths 50 is determined based on information on the signal quality of each optical signal after passing through each of the plurality of optical transmission paths 50.
  • a multi-core fiber in which a plurality of cores are arranged in a clad can be used for the plurality of optical transmission lines.
  • the input to one optical transmission line is based on the information related to the signal quality of all the optical signals that have passed through the plurality of optical transmission lines 50.
  • the light intensity is determined. That is, it is not optimized based on the signal quality of the optical signal passing through each optical transmission path, but is input to each optical transmission path in consideration of all the optical signals passing through the plurality of optical transmission paths.
  • the intensity of the optical signal is determined. Therefore, it is possible to optimize the characteristics of an optical transmission system using a plurality of optical transmission paths 50.
  • the light intensity control unit 120 selects the first optical transmission line having the highest signal quality from among the plurality of optical transmission lines 50 using information on the signal quality. Then, the set value of the light intensity of the input optical signal for the first optical transmission line can be reduced, and the light intensity after the reduction can be determined as the input light intensity for the first optical transmission line.
  • the light intensity control unit 120 may select the second optical transmission line having the lowest signal quality from the plurality of optical transmission lines 50 using the information on the signal quality. At this time, the set value of the light intensity of the input optical signal for the second optical transmission line may be increased, and the increased light intensity may be determined as the input light intensity for the second optical transmission line. At this time, the light intensity control unit 120 can perform an operation of increasing the set value of the light intensity within a range where the signal quality monotonously increases with respect to the light intensity.
  • the optical intensity of the input optical signal input to each of the plurality of optical transmission paths is controlled and set to a predetermined input optical intensity. Then, information on the signal quality of each optical signal after passing through each of the plurality of optical transmission paths is obtained, and based on the information on the signal quality at this time, the input light to at least one optical transmission path of the plurality of optical transmission paths Determine strength. Subsequently, the light intensity of the input optical signal is controlled based on the determined input light intensity.
  • the step of determining the input light intensity described above can be the following steps. That is, the first optical transmission line having the highest signal quality is selected from the plurality of optical transmission lines using information on the signal quality. Next, the set value of the light intensity of the input optical signal for the first optical transmission line is reduced, and the light intensity after the reduction is determined as the input light intensity for the first optical transmission line. In addition, the second optical transmission line having the lowest signal quality is selected from the plurality of optical transmission lines by using information on the signal quality. Subsequently, the set value of the light intensity of the input optical signal for the second optical transmission line is increased, and the increased light intensity can be determined as the input light intensity for the second optical transmission line.
  • optical transmission method of the present embodiment light that passes through a plurality of optical transmission paths is not optimized based on the signal quality of the optical signal that passes through each optical transmission path.
  • the intensity of the optical signal input to each optical transmission line is determined in consideration of all the signals. Therefore, it is possible to optimize the characteristics of an optical transmission system using a plurality of optical transmission paths.
  • FIG. 2 is a block diagram showing a configuration of an optical transmission apparatus 200 according to the second embodiment of the present invention.
  • the optical transmission device 200 includes a plurality of light intensity setting units 110 and a light intensity control unit 120 that controls each of the light intensity setting units 110.
  • the light intensity setting unit 110 controls the light intensity of the input optical signal 10 that is input to each of the plurality of optical transmission lines 50, and sets it to a predetermined input light intensity.
  • the light intensity control unit 120 determines the input light intensity for each of the plurality of optical transmission paths 50, and controls the plurality of light intensity setting units 110 based on the determined input light intensity. At this time, the input light intensity for at least one of the plurality of optical transmission paths 50 is determined based on information on the signal quality of each optical signal after passing through each of the plurality of optical transmission paths 50.
  • the optical transmission apparatus 200 further includes a signal quality estimation unit 210.
  • the signal quality estimation unit 210 uses at least a set value of the light intensity of the input optical signal, information on crosstalk between a plurality of optical transmission lines, and information on noise light intensity, as a signal quality estimation value as information on signal quality. Is calculated. Then, the signal quality estimation value is sent to the light intensity control unit 120.
  • the light intensity control unit 120 determines the input light intensity for at least one of the plurality of optical transmission paths 50 based on the signal quality estimation value.
  • optical transmission apparatus 200 of this embodiment will be described in more detail.
  • FIG. 3 is a block diagram showing a configuration of an optical transmission system 1000 using the optical transmission apparatus 200 according to the present embodiment.
  • the optical transmission system 1000 includes an optical transmission device 200, a plurality of optical transmission paths 50, a plurality of optical transmission devices 220, and a plurality of optical reception devices 230.
  • the plurality of optical transmission devices 220 transmit the plurality of optical signals to the plurality of light intensity setting units 110.
  • the plurality of optical receiving devices 230 receive the plurality of optical signals after passing through the plurality of optical transmission paths 50.
  • FIG. 3 shows a case where a multi-core fiber 500 including a plurality of optical transmission lines 50 is used.
  • the multi-core fiber 500 for example, seven cores arranged in the clad constitute a plurality of optical transmission lines 50.
  • the multi-core fiber 500 can be configured similarly to the related multi-core fiber 600 shown in FIG. That is, it can be set as the structure which has arrange
  • a case where multi-core fiber 500 is used as an optical transmission line and core multiplexed optical transmission using seven cores is performed will be described as an example.
  • each core a case where signals of the same wavelength are multiplexed will be described.
  • the control described below may be performed at each wavelength.
  • the optical transmission device 220 is configured to include seven optical transmission devices 221 to 227 corresponding to the seven cores 51 to 57.
  • Each of the optical transmitters 221 to 227 transmits a modulated optical signal, for example, a polarization multiplexed QPSK (Quadrature Phase Shift Keying) signal.
  • the seven optical signals transmitted from the optical transmitter 220 are input to the light intensity setting unit 110, respectively.
  • the light intensity setting unit 110 includes light intensity setting units 111 to 117 for individually adjusting the light intensity (input light intensity) of the input optical signals input to the cores 51 to 57, respectively. That is, the light intensity setting units 111 to 117 set the light intensities of the optical signals transmitted from the optical transmission devices 221 to 227 to predetermined input light intensities based on the control of the light intensity control unit 120, respectively.
  • the light intensity setting unit 110 is realized by, for example, an optical amplifier or an optical attenuator capable of gain control.
  • the set value of the input light intensity controlled by the light intensity control unit 120 is transferred to the signal quality estimation unit 210, and the received signal quality is estimated by the signal quality estimation unit 210.
  • the light intensity control unit 120 acquires a signal quality estimation value that is the received signal quality at each core estimated by the signal quality estimation unit 210. Then, the core having the best received signal quality is selected based on the signal quality estimation value. Then, the set value of the input light intensity at that time is reduced. Alternatively, the set value of the input light intensity in the core having the lowest received signal quality can be increased. By repeating these processes, the input light intensity is determined.
  • the optical intensity of the input optical signal is adjusted by the optical intensity setting unit 110, and the seven optical signals set to the respective input optical intensity are coupled to the multi-core fiber 500 and propagated.
  • the optical signal whose input light intensity is adjusted by the light intensity setting unit 111 is the core 51
  • the optical signal whose input light intensity is adjusted by the light intensity setting unit 112 is the core 52. Propagated by being coupled to each.
  • the optical signal propagated through the multi-core fiber 500 is received by the optical receiver 230.
  • the optical receiving device 230 includes seven optical receiving devices 231 to 237 for receiving optical signals core-multiplexed by seven cores. That is, the optical receivers 231 to 237 receive the optical signals propagated through the cores 51 to 57 constituting the multicore fiber 500, respectively.
  • the signal quality estimation unit 210 records information regarding the parameters of the multi-core fiber 500.
  • information about parameters for example, information on crosstalk between the cores of multi-core fiber 500, information on noise light intensity measured in advance, and the like can be used. Further, by recording the nonlinear coefficient in each core, it is possible to estimate the received signal quality more accurately.
  • the signal quality estimation unit 210 estimates the signal quality of each optical signal after passing through each core based on the information regarding these parameters and the set value of the light intensity of the input optical signal controlled by the light intensity control unit 120. .
  • an S / N (Signal / Noise) ratio obtained by adding a crosstalk component for one core to a noise component as shown below can be used.
  • S i is the light intensity of the optical signal transmitted through the core “i”
  • N i is the noise intensity
  • ⁇ j represents that a sum is taken for the core “j” adjacent to the core “i”.
  • ⁇ is a crosstalk amount between adjacent cores
  • ⁇ is a parameter considering the degree of influence of the crosstalk on the received signal quality, and is set according to the signal modulation method and the like.
  • Crosstalk can be treated in the same way as noise, and the values of ⁇ and ⁇ can be calculated in advance by measurement or evaluation.
  • the signal quality of the received signal can be estimated by using the above-described equation.
  • the value of ⁇ can be calculated by comparing the degradation amount of the signal quality of the received signal under the condition of adding noise or crosstalk of equal strength.
  • FIG. 4 is a flowchart for explaining a method by which the light intensity control unit 120 determines the input light intensity for each core.
  • the light intensity control unit 120 first sets the input light intensity in each core to an initial value, and sends the information to the signal quality estimation unit 210.
  • This initial value for example, it is the same for all the cores and can be the upper limit value of the input light intensity for each core.
  • the signal quality estimation unit 210 estimates the signal quality of the received signal based on the above-described equation based on the recorded information on the crosstalk between the cores of the multi-core fiber 500 (step S100).
  • the light intensity control unit 120 searches for the core with the lowest signal quality and the core with the highest signal quality using the signal quality estimation value of the received signal in each core estimated by the signal quality estimation unit 210 ( Step S200).
  • step S300 For the core with the highest signal quality of the received signal searched in this way, the set value of the input light intensity is reduced by a minute value (step S300).
  • Step S400 it is determined whether or not the set value of the input light intensity is within a range where the signal quality of the received signal increases monotonously with respect to the input light intensity.
  • the set value of the input light intensity is equal to or less than the threshold value that is the upper limit of the monotonically increasing range (step S400 / YES)
  • the set value of the input light intensity is increased by a small value (step S500). If the set value of the input light intensity is not within the monotonically increasing range (step S400 / NO), the process proceeds to the next step without increasing the set value of the input light intensity.
  • the set value of the input light intensity adjusted in this way is sent to the signal quality estimation unit 210 again.
  • the above operation is sufficiently repeated, and it is determined whether or not the number of repetitions is a predetermined number or more (step S600). If the number of repetitions is less than the predetermined number (step S600 / NO), the flow is repeated from the process of estimating the signal quality of the received signal (step S100) again using the set value of the input light intensity at this time. When the number of repetitions reaches a predetermined number (step S600 / YES), the process is terminated, and the set value of the input light intensity at this time is determined as the input light intensity in each core.
  • the light intensity control unit 120 sets the finally determined input light intensity in the light intensity setting unit 110.
  • the amount of crosstalk is reduced by reducing the light intensity of an optical signal transmitted through a core adjacent to one core. As a result, the signal quality of the received signal is improved. In addition, the relative crosstalk amount decreases as the optical intensity of the optical signal transmitted through one core increases. As a result, the signal quality of the received signal is improved. Therefore, by performing the control flow described above, it is possible to maximize the signal quality in the core where the signal quality of the received signal is the lowest.
  • the noise light intensity was set so that the optical S / N ratio (Optical Signal-to-Noise Ratio: OSNR) in the absence of crosstalk was 20 dB / 0.1 nm for all seven cores.
  • OSNR Optical Signal-to-Noise Ratio
  • the maximum value of the input light intensity is set to 0 dBm.
  • the input light intensity was 0 dBm for all seven cores.
  • the core 51 located at the center has the lowest signal quality, and the S / N ratio obtained from the above-described formula taking crosstalk into consideration was 10.8 dB.
  • FIG. 5 shows an example of the result of performing the processing flow for determining the input light intensity shown in FIG.
  • the horizontal axis represents the number of repetitions of the processing flow
  • the vertical axis represents the S / N ratio in consideration of crosstalk.
  • the processing flow was performed for the core having the lowest signal quality of the estimated received signal.
  • the initial value of the input light intensity was set to 0 dBm which is the maximum value of the input light intensity for all the cores.
  • the signal quality in the core having the lowest signal quality of the received signal can be maximized.
  • FIG. 6 is a block diagram illustrating a configuration of an optical transmission system 2000 using the optical transmission apparatus 300 according to the present embodiment.
  • the optical transmission system 2000 includes an optical transmission device 300, a plurality of optical transmission paths 50, a plurality of optical transmission devices 220, and a plurality of optical reception devices 230.
  • the plurality of optical transmission devices 220 transmit the plurality of optical signals to the plurality of light intensity setting units 110.
  • the plurality of optical receiving devices 230 receive the plurality of optical signals after passing through the plurality of optical transmission paths 50.
  • the optical transmission device 300 includes a plurality of light intensity setting units 110 and a light intensity control unit 120 that controls each of the light intensity setting units 110.
  • the light intensity setting unit 110 controls the light intensity of the input optical signal that is input to each of the plurality of optical transmission lines 50, and sets it to a predetermined input light intensity.
  • the light intensity control unit 120 determines the input light intensity for each of the plurality of optical transmission paths 50, and controls the plurality of light intensity setting units 110 based on the determined input light intensity. At this time, the light intensity control unit 120 inputs the input light intensity with respect to at least one of the plurality of optical transmission paths 50 based on the information on the signal quality of each optical signal after passing through the plurality of optical transmission paths 50 respectively. To decide.
  • the configuration so far is the same as that of the optical transmission apparatus 100 of the first embodiment.
  • the optical transmission apparatus 300 according to the present embodiment further includes a signal quality monitor unit 310.
  • the signal quality monitor unit 310 is disposed on the terminal end side of the plurality of optical transmission lines 50. Then, each optical signal after passing through each of the plurality of optical transmission lines 50 is detected to calculate a signal quality monitor value, and the signal quality monitor value at this time is sent to the light intensity control unit 120 as information on the signal quality. .
  • the optical transmission device 300 is different from the optical transmission device 200 according to the second embodiment in that a signal quality monitoring unit 310 is provided instead of the signal quality estimation unit 210.
  • the optical transmission apparatus 300 it is not necessary to previously measure parameters such as noise light intensity during optical transmission for each core of the multi-core fiber 500. Therefore, the signal quality of the received signal in the core having the lowest signal quality can be maximized by a simple control flow. As a result, it is possible to optimize the characteristics of an optical transmission system using a plurality of optical transmission paths 50.
  • the signal quality monitoring unit 310 can be configured to monitor the signal quality of the received signal by the optical receiving device 230 and calculate the signal quality monitor value.
  • the signal quality monitor value for example, a bit error rate before and after error correction of a signal or a margin from an FEC (Forward Error Correction) limit of a bit error rate before error correction can be used. Further, the spread of signal points represented by EVM (Error Vector Magnet) can be used.
  • the light intensity control unit 120 selects the core having the best signal quality of the received signal based on the signal quality monitor value received from the signal quality monitor unit 310, and the set value of the light intensity of the input optical signal at that time Reduce. Alternatively, the core having the lowest signal quality of the received signal is selected, and the set value of the light intensity of the input optical signal at that time is increased. By repeating such processing, the input light intensity in each core can be controlled, and the signal quality of the received signal in the core having the lowest signal quality can be maximized. At this time, the input light intensity is controlled within a range where the signal quality monotonously increases with respect to the light intensity in each core. Based on the input light intensity determined in this way, the light intensity control unit 120 controls the light intensity setting unit 110 to adjust the light intensity of the input optical signal input to each core.
  • the optical transmission device 300 in the optical transmission system 2000 using a multi-core fiber, the non-uniformity of the signal quality of the received signal between the cores is reduced, and the signal quality is the lowest. It becomes possible to maximize the signal quality of the core.
  • FIG. 7 is a block diagram showing a configuration of an optical transmission system 3000 using the optical transmission apparatus 400 according to the present embodiment.
  • the optical transmission system 3000 includes an optical transmission device 400, a plurality of optical transmission paths 50, a plurality of optical transmission devices 220, and a plurality of optical reception devices 230.
  • the plurality of optical transmission devices 220 transmit the plurality of optical signals to the plurality of light intensity setting units 110.
  • the plurality of optical receiving devices 230 receive the plurality of optical signals after passing through the plurality of optical transmission paths 50.
  • the optical transmission device 400 includes a plurality of light intensity setting units 110 and a light intensity control unit 120 that controls each of the light intensity setting units 110.
  • the light intensity setting unit 110 controls the light intensity of the input optical signal that is input to each of the plurality of optical transmission lines 50, and sets it to a predetermined input light intensity.
  • the light intensity control unit 120 determines the input light intensity for each of the plurality of optical transmission paths 50, and controls the plurality of light intensity setting units 110 based on the determined input light intensity. At this time, the input light intensity for at least one of the plurality of optical transmission paths 50 is determined based on information on the signal quality of each optical signal after passing through each of the plurality of optical transmission paths 50.
  • the optical transmission apparatus 400 further includes a plurality of termination side light intensity setting units 410 and a termination side light intensity control unit 420 on the termination side of the plurality of optical transmission lines 50.
  • the termination side light intensity setting unit 410 controls the light intensity of the output optical signals output from the terminations of the plurality of optical transmission lines 50, respectively, and sets it to a predetermined output light intensity.
  • the termination side light intensity control unit 420 determines the output light intensity for each of the plurality of optical transmission paths 50 according to the input light intensity, and sets the plurality of termination side light intensity setting units 410 based on the determined output light intensity. Control.
  • the optical transmission apparatus 400 includes the light intensity setting unit 110 at the start end of the multi-core fiber 500 including the plurality of optical transmission paths 50 as illustrated in FIG.
  • the light intensity setting unit 110 sets the input light intensity in each core under the control of the light intensity control unit 120.
  • the optical transmission device 400 further includes a termination-side light intensity setting unit 410 at the termination of the multi-core fiber 500.
  • the termination side light intensity setting unit 410 sets the output light intensity in each core under the control of the termination side light intensity control unit 420.
  • the termination-side light intensity control unit 420 outputs the output light intensity so that the total amount of change in the light intensity at the start-end light intensity setting unit 110 and the termination-end light intensity setting unit 410 is constant in each core. Can be determined.
  • the light intensity control unit 120 determines the signal quality of the received signal in the core with the lowest signal quality based on information from the signal quality estimation unit or the signal quality monitoring unit.
  • the input light intensity is set so that becomes the maximum.
  • the set value of the input light intensity of each core controlled by the light intensity control unit 120 and set in the light intensity setting unit 110 is sent to the termination-side light intensity control unit 420 disposed on the termination side of the multi-core fiber 500.
  • the termination side light intensity control unit 420 performs control so that the optical loss from the input of the light intensity setting unit 110 to the output of the termination side light intensity setting unit 410 is constant for each core.
  • the light intensity control unit 120 performs control so that the set value of the input light intensity in the light intensity setting unit 112 is decreased by 1 dB.
  • the termination-side light intensity control unit 420 performs control to increase the setting value of the corresponding termination-side light intensity setting unit 412 by 1 dB based on the set value of the input light intensity acquired from the light intensity control unit 120.
  • the total optical loss in the light intensity setting unit 110 and the termination side light intensity setting unit 410 can be set in advance so as to be a predetermined value for each core.
  • the start end of the multicore fiber can be obtained without changing the light intensity of the optical signal input to a device such as an optical receiver connected to the end of the multicore fiber. It becomes possible to control the input light intensity set by. As a result, the characteristics of the optical transmission system can be optimized without affecting the operation of the optical receiver or the like.
  • the configuration in which the light intensity setting unit for adjusting the input light intensity is arranged on the optical transmission device side of the optical transmission path has been described.
  • the present invention is not limited to this, and when the optical transmission device of this embodiment is used in an optical transmission system using a multi-core fiber in which an optical amplifier is arranged in the middle of an optical transmission line, a light intensity setting unit is arranged at a relay point. It can be configured. Even if it is a case where it is such a structure, the effect similar to the said embodiment is acquired.
  • Optical transmission system 100 1000, 2000, 3000 Optical transmission system 100, 200, 300, 400 Optical transmission device 110, 111-117 Optical intensity setting unit 120 Optical intensity control unit 210 Signal quality estimation unit 220, 221-227 Optical transmission device 230, 231-237 Optical receiver 310 Signal quality monitor unit 410 Termination side light intensity setting unit 420 Termination side light intensity control unit 500 Multicore fiber 600 Related multicore fiber 610 Core 620 Cladding 10 Input optical signal 50 Optical transmission line 51 to Core 57 Core

Abstract

In an optical transmission system in which a multicore fiber is used, it is difficult to optimize the characteristics of the optical transmission system. Therefore, this optical transmission device has a plurality of optical intensity setting units controlling the optical intensity of an input optical signal inputted into each of a plurality of optical transmission lines and setting the optical intensity to a predetermined input optical intensity, and an optical intensity controller for determining the input optical intensity for each of the optical transmission lines and controlling the optical intensity setting units on the basis of the determined input optical intensities. The optical intensity controller determines the input optical intensity for at least one of the optical transmission lines on the basis of information relating to the signal quality of each optical signal after having passed through the respective optical transmission lines.

Description

光伝送装置、光伝送システムおよび光伝送方法Optical transmission apparatus, optical transmission system, and optical transmission method
　本発明は、光伝送装置、光伝送システムおよび光伝送方法に関し、特に、マルチコアファイバなどの複数の光伝送路を用いる場合における光伝送装置、光伝送システムおよび光伝送方法に関する。 The present invention relates to an optical transmission device, an optical transmission system, and an optical transmission method, and more particularly to an optical transmission device, an optical transmission system, and an optical transmission method when a plurality of optical transmission paths such as a multi-core fiber are used.
　近年、データトラフィックの著しい増大を背景として、光通信のさらなる大容量化が求められている。大容量化を実現するための一つの技術として、マルチコアファイバやマルチモードファイバなどを利用した空間多重技術が注目を集めており、大容量伝送のデモンストレーションも行われている（例えば、非特許文献１を参照）。マルチコアファイバを用いた光伝送では、マルチコアファイバの複数のコアに信号を多重することによって、ファイバ１本あたりの伝送容量を増大することが可能になる。 In recent years, there has been a demand for further increase in optical communication capacity against the background of a significant increase in data traffic. As one technique for realizing a large capacity, a spatial multiplexing technique using a multi-core fiber, a multi-mode fiber or the like has attracted attention, and a demonstration of large-capacity transmission has been performed (for example, Non-Patent Document 1). See). In optical transmission using a multi-core fiber, it is possible to increase the transmission capacity per fiber by multiplexing signals on a plurality of cores of the multi-core fiber.
　このようなマルチコアファイバを用いた光伝送システムの一例が特許文献１に記載されている。特許文献１に記載された関連する光伝送システムにおいては、７コアの単一モード多芯ファイバ（マルチコアファイバ）が用いられている。図８に、関連するマルチコアファイバ６００の例示的な断面構成を示す。同図からわかるように、７つの個々のコア６１０は六角形の構成でクラッド６２０中に配置される。つまり、６つのコアが六角形の頂点の位置に配置され、１つのコアが六角形の中央に配置されている。 An example of an optical transmission system using such a multi-core fiber is described in Patent Document 1. In the related optical transmission system described in Patent Document 1, a 7-core single-mode multi-core fiber (multi-core fiber) is used. FIG. 8 illustrates an exemplary cross-sectional configuration of a related multicore fiber 600. As can be seen, the seven individual cores 610 are arranged in the cladding 620 in a hexagonal configuration. That is, six cores are arranged at the positions of the apexes of the hexagon, and one core is arranged at the center of the hexagon.
　関連する光伝送システムでは、単一モード多芯ファイバと光デバイスを接続するために、テーパー多芯コネクタが使用されている。ここで光デバイスには、波長分割多重（Ｗａｖｅｌｅｎｇｔｈ　Ｄｉｖｉｓｉｏｎ　Ｍｕｌｔｉｐｌｅｘｉｎｇ：ＷＤＭ）方式に対応した多重化デバイスおよび多重分離デバイスが用いられる。 In related optical transmission systems, tapered multicore connectors are used to connect single-mode multicore fibers and optical devices. Here, a multiplexing device and a demultiplexing device corresponding to the wavelength division multiplexing (WDM) system are used as the optical device.
　テーパー多芯コネクタは複数の光ファイバを含み、テーパー・カプラ本体で一緒にまとめられる。テーパー多芯コネクタは多芯ファイバの端面の外径と一致する外径を有する。さらに、テーパー多芯コネクタの端面は、コア直径、コア・ピッチ、モードフィールド・サイズ、モードフィールド形状などに関して、多芯ファイバのコアの構成と一致するコア構成を有している。テーパー・カプラ本体の端面は、カプラのコアがそれぞれの多芯ファイバのコアに位置合せされた状態で、多芯ファイバの端面に直接に接続される。そして個々の光ファイバが波長分割多重デバイスまたは偏波分割多重デバイスに接続される構成としている。 ∙ Tapered multi-core connectors include multiple optical fibers and are grouped together in a tapered coupler body. The tapered multicore connector has an outer diameter that matches the outer diameter of the end face of the multicore fiber. Furthermore, the end face of the tapered multicore connector has a core configuration that matches the core configuration of the multicore fiber with respect to the core diameter, core pitch, mode field size, mode field shape, and the like. The end face of the tapered coupler body is directly connected to the end face of the multicore fiber with the core of the coupler aligned with the core of each multicore fiber. Each optical fiber is connected to a wavelength division multiplexing device or a polarization division multiplexing device.
　このような構成により、ＷＤＭ方式による光伝送システムにおいて、空間分割多重（Ｓｐａｃｅ　Ｄｉｖｉｓｉｏｎ　Ｍｕｌｔｉｐｌｅｘｉｎｇ：ＳＤＭ）機能を実行でき、それにより伝送容量を増大させることができるとしている。 With such a configuration, in a WDM optical transmission system, it is possible to execute a space division multiplexing (SDM) function, thereby increasing transmission capacity.
特開２０１１－１９３４５９号公報（段落「００４１」～「００５３」、図７、図８）JP 2011-193459 A (paragraphs “0041” to “0053”, FIG. 7 and FIG. 8)
　上述したようなマルチコアファイバを用いた光伝送システムにおいては、複数のコア間でクロストークが生じることが知られており、これにより受信信号品質が劣化する。このクロストークによる信号品質の劣化に対して、様々な研究が行われている。例えば、マルチコアファイバにおける光伝送を多入力・多出力（Ｍｕｌｔｉｐｌｅ－Ｉｎｐｕｔ　Ｍｕｌｔｉｐｌｅ－Ｏｕｔｐｕｔ：ＭＩＭＯ）システムと見なし、信号処理技術によって補償する手法が検討されている。 In an optical transmission system using a multi-core fiber as described above, it is known that crosstalk occurs between a plurality of cores, which degrades the received signal quality. Various studies have been conducted on signal quality degradation due to crosstalk. For example, it is considered that optical transmission in a multi-core fiber is a multiple-input multiple-output (MIMO) system, and a method of compensating by a signal processing technique has been studied.
　一方、特許文献１に記載された関連する光伝送システムでは、シングルコアの光ファイバによる光伝送で用いられている１組の光送受信機を、マルチコアファイバのそれぞれのコアごとに割り当てて運用している。このような構成では、システムを分割して管理できるというメリットがある。しかし、この場合には以下に説明するように、それぞれのコアにおける受信信号の信号品質が不均一になる、という問題がある。 On the other hand, in the related optical transmission system described in Patent Document 1, a set of optical transceivers used in optical transmission by a single core optical fiber is allocated and operated for each core of the multicore fiber. Yes. Such a configuration has an advantage that the system can be divided and managed. However, in this case, as described below, there is a problem that the signal quality of the received signal in each core becomes non-uniform.
　すなわち、例えば、中心に位置するコアを伝送する光信号の強度が、周辺に配置されたコアを伝送する光信号の強度よりも極めて大きい場合を考える。この場合、周辺に配置されたコアを伝送する光信号はクロストークの影響を大きく受けるため、中心に位置するコアを伝送する光信号と比べて受信信号の品質が劣化する。その結果、各コアにおける受信信号の信号品質が不均一になる。 That is, for example, let us consider a case where the intensity of the optical signal transmitted through the core located at the center is extremely larger than the intensity of the optical signal transmitted through the core disposed in the periphery. In this case, since the optical signal transmitted through the core disposed in the periphery is greatly affected by the crosstalk, the quality of the received signal is deteriorated as compared with the optical signal transmitted through the core located at the center. As a result, the signal quality of the received signal in each core becomes non-uniform.
　この問題を回避するため、全てのコアを均一に扱い、各コアを伝送する光信号の変調方式および強度等を同一にした場合について検討する。コアの配置として図８に示した構成を例として説明すると、中心に位置するコアに隣接するコアの個数は６個であるのに対して、外周に位置するコアに隣接するコアの個数は３個である。このように、コアによって隣接するコアの個数は異なる。ここで、コア間に生じるクロストークに関しては、隣接しないコア同士のクロストークよりも隣接するコア同士のクロストークの方が大きい。そのため、隣接するコアの個数の相違によって、各コアを伝送する光信号の間に特性差が生じる。すなわち、マルチコアファイバを用いた光伝送においては、全てのコアを同一に扱い、各コアを伝送する光信号の条件を全て等しくした場合であっても、光信号を伝送するコアの配置によって各コアを伝送した後の受信信号の信号品質が均一とはならない。 In order to avoid this problem, we will consider the case where all cores are handled uniformly and the modulation method and intensity of the optical signal transmitted through each core are the same. The configuration shown in FIG. 8 will be described as an example of the arrangement of the cores. The number of cores adjacent to the core positioned at the center is six, whereas the number of cores adjacent to the core positioned at the outer periphery is three. It is a piece. Thus, the number of adjacent cores differs depending on the core. Here, regarding the crosstalk generated between the cores, the crosstalk between adjacent cores is larger than the crosstalk between non-adjacent cores. Therefore, due to the difference in the number of adjacent cores, a characteristic difference occurs between optical signals transmitted through the cores. In other words, in optical transmission using a multi-core fiber, even if all cores are handled in the same way and the conditions of optical signals transmitted through each core are all equal, each core is arranged depending on the arrangement of the cores transmitting optical signals. The signal quality of the received signal after transmitting is not uniform.
　上述したように、マルチコアファイバを用いた光伝送システムでは、各コア毎に任意に光伝送条件を設定することとすると、クロストークの発生により、受信信号の良好な信号品質を確保することは困難である。一方、全てのコアを同一に扱い、同じ条件で光伝送することとしても、各コアにおいて隣接するコアの個数が異なることから、受信信号の信号品質はやはり不均一になる。このとき、光伝送システムとして伝送可能な距離は、受信信号の信号品質が最も低くなるコアによって制限されることになる。そのため、個々のコアにおける光伝送条件が最適であっても、コア全体からなる光伝送システムとしての特性は最適とはならない。 As described above, in an optical transmission system using a multi-core fiber, if optical transmission conditions are arbitrarily set for each core, it is difficult to ensure good signal quality of a received signal due to the occurrence of crosstalk. It is. On the other hand, even if all the cores are handled in the same manner and optical transmission is performed under the same conditions, the signal quality of the received signal is still non-uniform because the number of adjacent cores is different in each core. At this time, the distance that can be transmitted as the optical transmission system is limited by the core having the lowest signal quality of the received signal. Therefore, even if the optical transmission conditions in each core are optimal, the characteristics as an optical transmission system composed of the entire core are not optimal.
　このように、マルチコアファイバを用いた光伝送システムにおいては、光伝送システムの特性を最適化することが困難である、という問題があった。 As described above, in an optical transmission system using a multi-core fiber, there is a problem that it is difficult to optimize the characteristics of the optical transmission system.
　本発明の目的は、上述した課題である、マルチコアファイバを用いた光伝送システムにおいては、光伝送システムの特性を最適化することが困難である、という課題を解決する光伝送装置、光伝送システムおよび光伝送方法を提供することにある。 An object of the present invention is to provide an optical transmission apparatus and an optical transmission system that solve the above-described problem that it is difficult to optimize the characteristics of an optical transmission system in an optical transmission system using a multi-core fiber. And providing an optical transmission method.
　本発明の光伝送装置は、複数の光伝送路にそれぞれ入力する入力光信号の光強度を制御し、所定の入力光強度に設定する複数の光強度設定部と、入力光強度を複数の光伝送路ごとにそれぞれ決定し、決定した入力光強度に基づいて複数の光強度設定部を制御する光強度制御部、を有し、光強度制御部は、複数の光伝送路をそれぞれ通過した後の各光信号の信号品質に関する情報に基づいて、複数の光伝送路の少なくとも一の光伝送路に対する入力光強度を決定する。 The optical transmission device of the present invention controls a light intensity of an input optical signal that is input to each of a plurality of optical transmission paths, sets a predetermined input light intensity, and sets the input light intensity to a plurality of lights. A light intensity control unit that determines each transmission path and controls a plurality of light intensity setting units based on the determined input light intensity, and the light intensity control unit passes through each of the plurality of optical transmission paths. The input light intensity for at least one of the plurality of optical transmission lines is determined based on the information relating to the signal quality of each optical signal.
　本発明の光伝送方法は、複数の光伝送路にそれぞれ入力する入力光信号の光強度を制御して所定の入力光強度に設定し、複数の光伝送路をそれぞれ通過した後の各光信号の信号品質に関する情報を取得し、信号品質に関する情報に基づいて、複数の光伝送路の少なくとも一の光伝送路に対する入力光強度を決定し、決定した入力光強度に基づいて入力光信号の光強度を制御する。 In the optical transmission method of the present invention, the optical intensity of the input optical signal input to each of the plurality of optical transmission paths is controlled to be set to a predetermined input optical intensity, and each optical signal after passing through the plurality of optical transmission paths, respectively. The information on the signal quality of the optical signal is acquired, the input light intensity for at least one of the plurality of optical transmission lines is determined based on the information on the signal quality, and the light of the input optical signal is determined based on the determined input light intensity. Control strength.
　本発明の光伝送装置、光伝送システムおよび光伝送方法によれば、マルチコアファイバを用いた光伝送システムにおいて、光伝送システムの特性を最適化することができる。 According to the optical transmission device, the optical transmission system, and the optical transmission method of the present invention, the characteristics of the optical transmission system can be optimized in the optical transmission system using the multi-core fiber.
本発明の第１の実施形態に係る光伝送装置の構成を示すブロック図である。1 is a block diagram illustrating a configuration of an optical transmission apparatus according to a first embodiment of the present invention. 本発明の第２の実施形態に係る光伝送装置の構成を示すブロック図である。It is a block diagram which shows the structure of the optical transmission apparatus which concerns on the 2nd Embodiment of this invention. 本発明の第２の実施形態に係る光伝送システムの構成を示すブロック図である。It is a block diagram which shows the structure of the optical transmission system which concerns on the 2nd Embodiment of this invention. 本発明の第２の実施形態に係る光伝送装置の光強度制御部が入力光強度を決定する方法を説明するためのフローチャートである。It is a flowchart for demonstrating the method in which the light intensity control part of the optical transmission apparatus which concerns on the 2nd Embodiment of this invention determines input light intensity. 本発明の第２の実施形態に係る光伝送装置において、入力光強度を決定する処理フローを行った結果を示す図である。It is a figure which shows the result of having performed the processing flow which determines input light intensity in the optical transmission apparatus which concerns on the 2nd Embodiment of this invention. 本発明の第３の実施形態に係る光伝送システムの構成を示すブロック図である。It is a block diagram which shows the structure of the optical transmission system which concerns on the 3rd Embodiment of this invention. 本発明の第４の実施形態に係る光伝送システムの構成を示すブロック図である。It is a block diagram which shows the structure of the optical transmission system which concerns on the 4th Embodiment of this invention. 関連するマルチコアファイバの概略構成を示す断面図である。It is sectional drawing which shows schematic structure of a related multi-core fiber.
　以下に、図面を参照しながら、本発明の実施形態について説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　〔第１の実施形態〕
　図１は、本発明の第１の実施形態に係る光伝送装置１００の構成を示すブロック図である。光伝送装置１００は、複数の光強度設定部１１０と、それぞれの光強度設定部１１０を制御する光強度制御部１２０を有する。光強度設定部１１０は、複数の光伝送路５０にそれぞれ入力する入力光信号１０の光強度を制御し、所定の入力光強度に設定する。 [First Embodiment]
FIG. 1 is a block diagram showing a configuration of an optical transmission apparatus 100 according to the first embodiment of the present invention. The optical transmission device 100 includes a plurality of light intensity setting units 110 and a light intensity control unit 120 that controls each light intensity setting unit 110. The light intensity setting unit 110 controls the light intensity of the input optical signal 10 that is input to each of the plurality of optical transmission lines 50, and sets it to a predetermined input light intensity.
　光強度制御部１２０は、入力光強度を複数の光伝送路５０ごとにそれぞれ決定し、決定した入力光強度に基づいて複数の光強度設定部１１０を制御する。このとき、複数の光伝送路５０をそれぞれ通過した後の各光信号の信号品質に関する情報に基づいて、複数の光伝送路５０の少なくとも一の光伝送路に対する入力光強度を決定する。ここで複数の光伝送路には、クラッド中に複数のコアが配置されたマルチコアファイバを用いることができる。 The light intensity control unit 120 determines the input light intensity for each of the plurality of optical transmission paths 50, and controls the plurality of light intensity setting units 110 based on the determined input light intensity. At this time, the input light intensity for at least one of the plurality of optical transmission paths 50 is determined based on information on the signal quality of each optical signal after passing through each of the plurality of optical transmission paths 50. Here, a multi-core fiber in which a plurality of cores are arranged in a clad can be used for the plurality of optical transmission lines.
　このような構成とすることにより、本実施形態の光伝送装置１００によれば、複数の光伝送路５０を通過した全ての光信号の信号品質に関する情報に基づいて、一の光伝送路に対する入力光強度が決定される。すなわち、個々の光伝送路を通過する光信号の信号品質に基づいて最適化されるのではなく、複数の光伝送路を通過する光信号の全てを考慮して個々の光伝送路に入力する光信号の強度が定められる。そのため、複数の光伝送路５０を用いた光伝送システムの特性を最適化することが可能になる。 With this configuration, according to the optical transmission device 100 of the present embodiment, the input to one optical transmission line is based on the information related to the signal quality of all the optical signals that have passed through the plurality of optical transmission lines 50. The light intensity is determined. That is, it is not optimized based on the signal quality of the optical signal passing through each optical transmission path, but is input to each optical transmission path in consideration of all the optical signals passing through the plurality of optical transmission paths. The intensity of the optical signal is determined. Therefore, it is possible to optimize the characteristics of an optical transmission system using a plurality of optical transmission paths 50.
　具体的には例えば、光強度制御部１２０は信号品質に関する情報を用いて、複数の光伝送路５０の中から信号品質が最高である第１の光伝送路を選択する。そして、第１の光伝送路に対する入力光信号の光強度の設定値を低減し、低減した後の光強度を第１の光伝送路に対する入力光強度に決定することができる。 Specifically, for example, the light intensity control unit 120 selects the first optical transmission line having the highest signal quality from among the plurality of optical transmission lines 50 using information on the signal quality. Then, the set value of the light intensity of the input optical signal for the first optical transmission line can be reduced, and the light intensity after the reduction can be determined as the input light intensity for the first optical transmission line.
　また、光強度制御部１２０は信号品質に関する情報を用いて、複数の光伝送路５０の中から信号品質が最低である第２の光伝送路を選択することとしてもよい。このときは、第２の光伝送路に対する入力光信号の光強度の設定値を増加し、増加した後の光強度を第２の光伝送路に対する入力光強度に決定することとすればよい。このとき、光強度制御部１２０は信号品質が光強度に対して単調に増加する範囲内で、光強度の設定値を増加する動作を行うこととすることができる。 Further, the light intensity control unit 120 may select the second optical transmission line having the lowest signal quality from the plurality of optical transmission lines 50 using the information on the signal quality. At this time, the set value of the light intensity of the input optical signal for the second optical transmission line may be increased, and the increased light intensity may be determined as the input light intensity for the second optical transmission line. At this time, the light intensity control unit 120 can perform an operation of increasing the set value of the light intensity within a range where the signal quality monotonously increases with respect to the light intensity.
　また、本実施形態による光伝送方法においては、まず、複数の光伝送路にそれぞれ入力する入力光信号の光強度を制御して所定の入力光強度に設定する。そして複数の光伝送路をそれぞれ通過した後の各光信号の信号品質に関する情報を取得し、このときの信号品質に関する情報に基づいて、複数の光伝送路の少なくとも一の光伝送路に対する入力光強度を決定する。続いて、決定した入力光強度に基づいて入力光信号の光強度を制御する。 In the optical transmission method according to the present embodiment, first, the optical intensity of the input optical signal input to each of the plurality of optical transmission paths is controlled and set to a predetermined input optical intensity. Then, information on the signal quality of each optical signal after passing through each of the plurality of optical transmission paths is obtained, and based on the information on the signal quality at this time, the input light to at least one optical transmission path of the plurality of optical transmission paths Determine strength. Subsequently, the light intensity of the input optical signal is controlled based on the determined input light intensity.
　上述した入力光強度を決定する工程は、以下の工程とすることができる。すなわち、信号品質に関する情報を用いて、複数の光伝送路の中から信号品質が最高である第１の光伝送路を選択する。次に、第１の光伝送路に対する入力光信号の光強度の設定値を低減し、低減した後の光強度を第１の光伝送路に対する入力光強度に決定する。また、信号品質に関する情報を用いて、複数の光伝送路の中から信号品質が最低である第２の光伝送路を選択する。続いて、第２の光伝送路に対する入力光信号の光強度の設定値を増加し、増加した後の光強度を第２の光伝送路に対する入力光強度に決定することができる。 The step of determining the input light intensity described above can be the following steps. That is, the first optical transmission line having the highest signal quality is selected from the plurality of optical transmission lines using information on the signal quality. Next, the set value of the light intensity of the input optical signal for the first optical transmission line is reduced, and the light intensity after the reduction is determined as the input light intensity for the first optical transmission line. In addition, the second optical transmission line having the lowest signal quality is selected from the plurality of optical transmission lines by using information on the signal quality. Subsequently, the set value of the light intensity of the input optical signal for the second optical transmission line is increased, and the increased light intensity can be determined as the input light intensity for the second optical transmission line.
　このような構成により、本実施形態の光伝送方法によれば、個々の光伝送路を通過する光信号の信号品質に基づいて最適化されるのではなく、複数の光伝送路を通過する光信号の全てを考慮して個々の光伝送路に入力する光信号の強度が定められる。そのため、複数の光伝送路を用いた光伝送システムの特性を最適化することが可能になる。 With such a configuration, according to the optical transmission method of the present embodiment, light that passes through a plurality of optical transmission paths is not optimized based on the signal quality of the optical signal that passes through each optical transmission path. The intensity of the optical signal input to each optical transmission line is determined in consideration of all the signals. Therefore, it is possible to optimize the characteristics of an optical transmission system using a plurality of optical transmission paths.
　〔第２の実施形態〕
　次に、本発明の第２の実施形態について説明する。図２は、本発明の第２の実施形態に係る光伝送装置２００の構成を示すブロック図である。 [Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 2 is a block diagram showing a configuration of an optical transmission apparatus 200 according to the second embodiment of the present invention.
　光伝送装置２００は、複数の光強度設定部１１０と、それぞれの光強度設定部１１０を制御する光強度制御部１２０を有する。光強度設定部１１０は、複数の光伝送路５０にそれぞれ入力する入力光信号１０の光強度を制御し、所定の入力光強度に設定する。 The optical transmission device 200 includes a plurality of light intensity setting units 110 and a light intensity control unit 120 that controls each of the light intensity setting units 110. The light intensity setting unit 110 controls the light intensity of the input optical signal 10 that is input to each of the plurality of optical transmission lines 50, and sets it to a predetermined input light intensity.
　光強度制御部１２０は、入力光強度を複数の光伝送路５０ごとにそれぞれ決定し、決定した入力光強度に基づいて複数の光強度設定部１１０を制御する。このとき、複数の光伝送路５０をそれぞれ通過した後の各光信号の信号品質に関する情報に基づいて、複数の光伝送路５０の少なくとも一の光伝送路に対する入力光強度を決定する。 The light intensity control unit 120 determines the input light intensity for each of the plurality of optical transmission paths 50, and controls the plurality of light intensity setting units 110 based on the determined input light intensity. At this time, the input light intensity for at least one of the plurality of optical transmission paths 50 is determined based on information on the signal quality of each optical signal after passing through each of the plurality of optical transmission paths 50.
　ここまでの構成は第１の実施形態の光伝送装置１００と同様である。本実施形態による光伝送装置２００は、信号品質推定部２１０をさらに有する。信号品質推定部２１０は、少なくとも入力光信号の光強度の設定値と、複数の光伝送路間のクロストークに関する情報、および雑音光強度に関する情報とから、信号品質に関する情報としての信号品質推定値を算出する。そして、信号品質推定値を光強度制御部１２０に送出する。光強度制御部１２０は信号品質推定値に基づいて、複数の光伝送路５０の少なくとも一の光伝送路に対する入力光強度を決定する。 The configuration so far is the same as that of the optical transmission apparatus 100 of the first embodiment. The optical transmission apparatus 200 according to the present embodiment further includes a signal quality estimation unit 210. The signal quality estimation unit 210 uses at least a set value of the light intensity of the input optical signal, information on crosstalk between a plurality of optical transmission lines, and information on noise light intensity, as a signal quality estimation value as information on signal quality. Is calculated. Then, the signal quality estimation value is sent to the light intensity control unit 120. The light intensity control unit 120 determines the input light intensity for at least one of the plurality of optical transmission paths 50 based on the signal quality estimation value.
　このような構成とすることにより、本実施形態の光伝送装置２００によれば、複数の光伝送路５０を通過する光信号の全てを考慮して個々の光伝送路に入力する光信号の強度が定められる。そのため、複数の光伝送路５０を用いた光伝送システムの特性を最適化することが可能になる。 With such a configuration, according to the optical transmission device 200 of the present embodiment, the intensity of the optical signal input to each optical transmission line in consideration of all of the optical signals passing through the plurality of optical transmission lines 50. Is determined. Therefore, it is possible to optimize the characteristics of an optical transmission system using a plurality of optical transmission paths 50.
　次に、本実施形態の光伝送装置２００について、さらに詳細に説明する。 Next, the optical transmission apparatus 200 of this embodiment will be described in more detail.
　図３は、本実施形態による光伝送装置２００を用いた光伝送システム１０００の構成を示すブロック図である。光伝送システム１０００は、光伝送装置２００と、複数の光伝送路５０、複数の光送信装置２２０、および複数の光受信装置２３０とを有する。複数の光送信装置２２０は、複数の光信号を複数の光強度設定部１１０に送出する。複数の光受信装置２３０は、複数の光伝送路５０を通過した後の複数の光信号を受光する。 FIG. 3 is a block diagram showing a configuration of an optical transmission system 1000 using the optical transmission apparatus 200 according to the present embodiment. The optical transmission system 1000 includes an optical transmission device 200, a plurality of optical transmission paths 50, a plurality of optical transmission devices 220, and a plurality of optical reception devices 230. The plurality of optical transmission devices 220 transmit the plurality of optical signals to the plurality of light intensity setting units 110. The plurality of optical receiving devices 230 receive the plurality of optical signals after passing through the plurality of optical transmission paths 50.
　図３では、複数の光伝送路５０を含むマルチコアファイバ５００を用いる場合を示す。マルチコアファイバ５００において、クラッド中に配置された例えば７個のコアが複数の光伝送路５０を構成する。マルチコアファイバ５００は図８に示した関連するマルチコアファイバ６００と同様の構成とすることができる。すなわち、正六角形の中心位置と各頂点位置にコアを配置した構成とすることができる。以下では、マルチコアファイバ５００を光伝送路として用い、7個のコアを使用したコア多重光伝送を行う場合を例として説明する。 FIG. 3 shows a case where a multi-core fiber 500 including a plurality of optical transmission lines 50 is used. In the multi-core fiber 500, for example, seven cores arranged in the clad constitute a plurality of optical transmission lines 50. The multi-core fiber 500 can be configured similarly to the related multi-core fiber 600 shown in FIG. That is, it can be set as the structure which has arrange | positioned the core in the center position of a regular hexagon, and each vertex position. In the following, a case where multi-core fiber 500 is used as an optical transmission line and core multiplexed optical transmission using seven cores is performed will be described as an example.
　それぞれのコアでは、同じ波長の信号を多重する場合について説明する。それぞれのコアで波長多重を行う場合には、各波長において以下で説明する制御を行うこととすればよい。 In each core, a case where signals of the same wavelength are multiplexed will be described. When wavelength multiplexing is performed in each core, the control described below may be performed at each wavelength.
　以下の説明では、各コアを区別する必要があるときには、中心に位置するコアをコア５１と表記し、外周に位置するコアをコア５２～コア５７と表記する。光送信装置２２０は、７個のコア５１～５７に対応した７個の光送信装置２２１～２２７を含んで構成される。光送信装置２２１～２２７はそれぞれ変調された光信号、例えば偏波多重ＱＰＳＫ（Ｑｕａｄｒａｔｕｒｅ　Ｐｈａｓｅ　Ｓｈｉｆｔ　Ｋｅｙｉｎｇ）信号を送出する。光送信装置２２０から送出された７個の光信号は光強度設定部１１０にそれぞれ入力する。 In the following description, when it is necessary to distinguish each core, the core located at the center is denoted as core 51, and the cores located at the outer periphery are denoted as core 52 to core 57. The optical transmission device 220 is configured to include seven optical transmission devices 221 to 227 corresponding to the seven cores 51 to 57. Each of the optical transmitters 221 to 227 transmits a modulated optical signal, for example, a polarization multiplexed QPSK (Quadrature Phase Shift Keying) signal. The seven optical signals transmitted from the optical transmitter 220 are input to the light intensity setting unit 110, respectively.
　光強度設定部１１０は、それぞれのコア５１～５７に入力する入力光信号の光強度（入力光強度）を個別に調整するための光強度設定部１１１～１１７を含んで構成される。すなわち、光強度設定部１１１～１１７は、光強度制御部１２０の制御に基づいて、光送信装置２２１～２２７から送出された光信号の光強度を所定の入力光強度にそれぞれ設定する。光強度設定部１１０は具体的には例えば、ゲイン制御可能な光アンプや光アッテネータによって実現される。 The light intensity setting unit 110 includes light intensity setting units 111 to 117 for individually adjusting the light intensity (input light intensity) of the input optical signals input to the cores 51 to 57, respectively. That is, the light intensity setting units 111 to 117 set the light intensities of the optical signals transmitted from the optical transmission devices 221 to 227 to predetermined input light intensities based on the control of the light intensity control unit 120, respectively. Specifically, the light intensity setting unit 110 is realized by, for example, an optical amplifier or an optical attenuator capable of gain control.
　光強度制御部１２０で制御される入力光強度の設定値は、信号品質推定部２１０に受け渡され、信号品質推定部２１０において受信信号品質が推定される。光強度制御部１２０は信号品質推定部２１０において推定されたそれぞれのコアでの受信信号品質である信号品質推定値を取得する。そして、この信号品質推定値に基づいて受信信号品質が最も良好なコアを選択する。そして、そのときの入力光強度の設定値を低減する。あるいは、受信信号品質が最低であるコアにおける入力光強度の設定値を増加することができる。これらの処理を繰り返し行うことにより、入力光強度を決定する。 The set value of the input light intensity controlled by the light intensity control unit 120 is transferred to the signal quality estimation unit 210, and the received signal quality is estimated by the signal quality estimation unit 210. The light intensity control unit 120 acquires a signal quality estimation value that is the received signal quality at each core estimated by the signal quality estimation unit 210. Then, the core having the best received signal quality is selected based on the signal quality estimation value. Then, the set value of the input light intensity at that time is reduced. Alternatively, the set value of the input light intensity in the core having the lowest received signal quality can be increased. By repeating these processes, the input light intensity is determined.
　このとき、各コアを伝送する光信号の光強度と受信信号品質の関係が単調増加となる光強度の範囲を予め測定しておき、この範囲で入力光強度の制御を行うことが望ましい。そのためには、一のコアだけを用いて光信号を伝送し、そのときの入力光強度と受信信号品質との関係を記録しておけばよい。一般に、ファイバ中の非線形効果により、ファイバ中を伝送する光信号は劣化する。そのため、入力光強度の設定値を増加させることによって受信信号品質を改善できる範囲には上限が存在する。このことから、各コアにおける入力光強度と受信信号品質との関係が単調増加な関係となる範囲が制限されることになる。また、光伝送システムで使用されるデバイス上の制限によっても、上記範囲が制限される場合がある。 At this time, it is desirable to measure in advance a light intensity range in which the relationship between the light intensity of the optical signal transmitted through each core and the received signal quality monotonously increases, and to control the input light intensity within this range. For this purpose, it is only necessary to transmit an optical signal using only one core and record the relationship between the input light intensity and the received signal quality at that time. In general, an optical signal transmitted through a fiber is deteriorated due to a nonlinear effect in the fiber. For this reason, there is an upper limit in the range in which the received signal quality can be improved by increasing the set value of the input light intensity. This limits the range in which the relationship between the input light intensity and the received signal quality in each core is monotonically increasing. In addition, the above range may be limited due to limitations on devices used in the optical transmission system.
　光強度設定部１１０によって入力光信号の光強度を調整され、それぞれの入力光強度に設定された７個の光信号は、マルチコアファイバ５００に結合されて伝播する。具体的には、図３に示すように、光強度設定部１１１によって入力光強度を調整された光信号はコア５１に、光強度設定部１１２によって入力光強度を調整された光信号はコア５２にそれぞれ結合されて伝播する。 The optical intensity of the input optical signal is adjusted by the optical intensity setting unit 110, and the seven optical signals set to the respective input optical intensity are coupled to the multi-core fiber 500 and propagated. Specifically, as shown in FIG. 3, the optical signal whose input light intensity is adjusted by the light intensity setting unit 111 is the core 51, and the optical signal whose input light intensity is adjusted by the light intensity setting unit 112 is the core 52. Propagated by being coupled to each.
　マルチコアファイバ５００を伝播した光信号は光受信装置２３０で受信される。光受信装置２３０は、７個のコアでコア多重された光信号をそれぞれ受信するための７個の光受信装置２３１～２３７を含んで構成される。すなわち、光受信装置２３１～２３７はマルチコアファイバ５００を構成するコア５１～５７を伝播した光信号をそれぞれ受信する。 The optical signal propagated through the multi-core fiber 500 is received by the optical receiver 230. The optical receiving device 230 includes seven optical receiving devices 231 to 237 for receiving optical signals core-multiplexed by seven cores. That is, the optical receivers 231 to 237 receive the optical signals propagated through the cores 51 to 57 constituting the multicore fiber 500, respectively.
　次に、信号品質推定部２１０の動作について説明する。 Next, the operation of the signal quality estimation unit 210 will be described.
　信号品質推定部２１０は、マルチコアファイバ５００のパラメータに関する情報を記録する。パラメータに関する情報としては例えば、マルチコアファイバ５００の各コア間のクロストークに関する情報、および予め測定された雑音光強度に関する情報等を用いることができる。また、各コアにおける非線形係数を記録しておくことにより、さらに正確な受信信号品質の推定が可能になる。信号品質推定部２１０は、これらのパラメータに関する情報と光強度制御部１２０によって制御される入力光信号の光強度の設定値により、各コアをそれぞれ通過した後の各光信号の信号品質を推定する。 The signal quality estimation unit 210 records information regarding the parameters of the multi-core fiber 500. As information about parameters, for example, information on crosstalk between the cores of multi-core fiber 500, information on noise light intensity measured in advance, and the like can be used. Further, by recording the nonlinear coefficient in each core, it is possible to estimate the received signal quality more accurately. The signal quality estimation unit 210 estimates the signal quality of each optical signal after passing through each core based on the information regarding these parameters and the set value of the light intensity of the input optical signal controlled by the light intensity control unit 120. .
　上述した各コアにおける信号品質の推定には、下記に示すような、一のコアに対するクロストーク成分をノイズ成分に加算したＳ／Ｎ（Ｓｉｇｎａｌ／Ｎｏｉｓｅ）比を用いることができる。
Figure JPOXMLDOC01-appb-I000001
For estimation of signal quality in each core described above, an S / N (Signal / Noise) ratio obtained by adding a crosstalk component for one core to a noise component as shown below can be used.
Figure JPOXMLDOC01-appb-I000001
　ここで、Ｓｉはコア「ｉ」を伝送する光信号の光強度、Ｎｉはノイズ強度であり、Σｊはコア「ｉ」に隣接するコア「ｊ」について和をとることを表す。また、Γは隣接コア間のクロストーク量、μはクロストークが受信信号品質へ影響する度合いを考慮したパラメータであり、信号の変調方式等に応じて設定される。クロストークはノイズと同様に扱うことができ、また、Γおよびμの値はあらかじめ測定または評価により算出することが可能である。以上より、上記した式を用いることによって受信信号の信号品質を推定することができる。例えばμの値は、等しい強度のノイズまたはクロストークを付加した条件で、受信信号の信号品質の劣化量を比較することから算出することが可能である。 Here, S i is the light intensity of the optical signal transmitted through the core “i”, N i is the noise intensity, and Σ j represents that a sum is taken for the core “j” adjacent to the core “i”. Further, Γ is a crosstalk amount between adjacent cores, and μ is a parameter considering the degree of influence of the crosstalk on the received signal quality, and is set according to the signal modulation method and the like. Crosstalk can be treated in the same way as noise, and the values of Γ and μ can be calculated in advance by measurement or evaluation. As described above, the signal quality of the received signal can be estimated by using the above-described equation. For example, the value of μ can be calculated by comparing the degradation amount of the signal quality of the received signal under the condition of adding noise or crosstalk of equal strength.
　次に、光強度制御部１２０が各コアに対する入力光強度を決定する方法について、さらに詳細に説明する。図４は、光強度制御部１２０が各コアに対する入力光強度を決定する方法を説明するためのフローチャートである。 Next, the method by which the light intensity controller 120 determines the input light intensity for each core will be described in more detail. FIG. 4 is a flowchart for explaining a method by which the light intensity control unit 120 determines the input light intensity for each core.
　光強度制御部１２０は、まず、各コアにおける入力光強度を初期値に設定し、その情報を信号品質推定部２１０に送出する。この初期値として例えば、全てのコアに対して等しく、各コアに対する入力光強度の上限値とすることができる。信号品質推定部２１０は、記録されているマルチコアファイバ５００の各コア間のクロストークに関する情報等に基づいて、上述した式によって受信信号の信号品質を推定する（ステップＳ１００）。 The light intensity control unit 120 first sets the input light intensity in each core to an initial value, and sends the information to the signal quality estimation unit 210. As this initial value, for example, it is the same for all the cores and can be the upper limit value of the input light intensity for each core. The signal quality estimation unit 210 estimates the signal quality of the received signal based on the above-described equation based on the recorded information on the crosstalk between the cores of the multi-core fiber 500 (step S100).
　次に、光強度制御部１２０は信号品質推定部２１０が推定した各コアにおける受信信号の信号品質推定値を用いて、信号品質が最低であるコアと信号品質が最高であるコアを探索する（ステップＳ２００）。 Next, the light intensity control unit 120 searches for the core with the lowest signal quality and the core with the highest signal quality using the signal quality estimation value of the received signal in each core estimated by the signal quality estimation unit 210 ( Step S200).
　このようにして探索された受信信号の信号品質が最高であるコアについて、入力光強度の設定値をある微小な値だけ低減する（ステップＳ３００）。 For the core with the highest signal quality of the received signal searched in this way, the set value of the input light intensity is reduced by a minute value (step S300).
　次に、受信信号の信号品質が最低であるコアについて、入力光強度の設定値が、受信信号の信号品質が入力光強度に対して単調に増加する範囲内にあるか否かを判断する（ステップＳ４００）。入力光強度の設定値が、単調に増加する範囲の上限である閾値以下である場合（ステップＳ４００／ＹＥＳ）、入力光強度の設定値をある微小な値だけ増加する（ステップＳ５００）。入力光強度の設定値が単調に増加する範囲内にない場合（ステップＳ４００／ＮＯ）、入力光強度の設定値を増加させることなく次のステップに進む。 Next, for the core having the lowest signal quality of the received signal, it is determined whether or not the set value of the input light intensity is within a range where the signal quality of the received signal increases monotonously with respect to the input light intensity ( Step S400). When the set value of the input light intensity is equal to or less than the threshold value that is the upper limit of the monotonically increasing range (step S400 / YES), the set value of the input light intensity is increased by a small value (step S500). If the set value of the input light intensity is not within the monotonically increasing range (step S400 / NO), the process proceeds to the next step without increasing the set value of the input light intensity.
　このようにして調整した入力光強度の設定値を再び信号品質推定部２１０に送出する。以上の動作を十分に繰り返し、繰り返し回数が所定の回数以上か否か判断する（ステップＳ６００）。繰り返し回数が所定の回数に満たない場合（ステップＳ６００／ＮＯ）、このときの入力光強度の設定値を用いて再度、受信信号の信号品質を推定する処理（ステップＳ１００）からフローを繰り返す。繰り返し回数が所定の回数に達した場合（ステップＳ６００／ＹＥＳ）、処理を終了し、このときの入力光強度の設定値を各コアにおける入力光強度に決定する。光強度制御部１２０は、この最終的に決定された入力光強度を光強度設定部１１０に設定する。 The set value of the input light intensity adjusted in this way is sent to the signal quality estimation unit 210 again. The above operation is sufficiently repeated, and it is determined whether or not the number of repetitions is a predetermined number or more (step S600). If the number of repetitions is less than the predetermined number (step S600 / NO), the flow is repeated from the process of estimating the signal quality of the received signal (step S100) again using the set value of the input light intensity at this time. When the number of repetitions reaches a predetermined number (step S600 / YES), the process is terminated, and the set value of the input light intensity at this time is determined as the input light intensity in each core. The light intensity control unit 120 sets the finally determined input light intensity in the light intensity setting unit 110.
　マルチコアファイバを用いた光伝送においては、一つのコアに隣接するコアを伝送する光信号の光強度が低減することによってクロストーク量が減少する。その結果、受信信号の信号品質が改善する。また、一つのコアを伝送する光信号の光強度が増加することによって、相対的なクロストーク量が減少する。その結果、受信信号の信号品質が改善する。したがって、上述した制御フローを行うことによって、受信信号の信号品質が最低であるコアにおける信号品質を最大化することが可能となる。 In optical transmission using a multi-core fiber, the amount of crosstalk is reduced by reducing the light intensity of an optical signal transmitted through a core adjacent to one core. As a result, the signal quality of the received signal is improved. In addition, the relative crosstalk amount decreases as the optical intensity of the optical signal transmitted through one core increases. As a result, the signal quality of the received signal is improved. Therefore, by performing the control flow described above, it is possible to maximize the signal quality in the core where the signal quality of the received signal is the lowest.
　次に、クロストークの影響を加味したＳ／Ｎ比の数値計算結果について説明する。ここでは、隣接するコア間のクロストークを－２０ｄＢ、μ＝１とした。また雑音光強度は、クロストークがない場合における光Ｓ／Ｎ比（Ｏｐｔｉｃａｌ　Ｓｉｇｎａｌ－ｔｏ－Ｎｏｉｓｅ　Ｒａｔｉｏ：ＯＳＮＲ）が、7個のコアの全てで２０ｄＢ／０．１ｎｍとなるように設定した。受信信号の信号品質が入力光強度に対して単調に増加する範囲における、入力光強度の最大値は０ｄＢｍとした。また、入力光強度は、7個のコアの全てに対して０ｄＢｍとした。 Next, the numerical calculation result of the S / N ratio in consideration of the influence of crosstalk will be described. Here, the crosstalk between adjacent cores was set to −20 dB and μ = 1. The noise light intensity was set so that the optical S / N ratio (Optical Signal-to-Noise Ratio: OSNR) in the absence of crosstalk was 20 dB / 0.1 nm for all seven cores. In the range where the signal quality of the received signal monotonously increases with respect to the input light intensity, the maximum value of the input light intensity is set to 0 dBm. The input light intensity was 0 dBm for all seven cores.
　数値計算の結果、信号品質が最低となるのは中心に位置するコア５１であり、クロストークを加味した上述した式から求められるＳ／Ｎ比は１０．８ｄＢであった。 As a result of the numerical calculation, the core 51 located at the center has the lowest signal quality, and the S / N ratio obtained from the above-described formula taking crosstalk into consideration was 10.8 dB.
　図５に、図４に示した入力光強度を決定する処理フローを行った結果の一例を示す。同図の横軸は処理フローの繰り返し回数、縦軸はクロストークを加味したＳ／Ｎ比である。処理フローは、推定される受信信号の信号品質が最低であるコアについて行った。入力光強度の初期値は全てのコアに対して、入力光強度の最大値である０ｄＢｍとした。 FIG. 5 shows an example of the result of performing the processing flow for determining the input light intensity shown in FIG. In the figure, the horizontal axis represents the number of repetitions of the processing flow, and the vertical axis represents the S / N ratio in consideration of crosstalk. The processing flow was performed for the core having the lowest signal quality of the estimated received signal. The initial value of the input light intensity was set to 0 dBm which is the maximum value of the input light intensity for all the cores.
　図５から、クロストークを加味したＳ／Ｎ比は繰り返し回数の増加に従って改善し、繰り返しがないときの値から１ｄＢ程度改善した１１．８ｄＢに収束していることが分かる。 From FIG. 5, it can be seen that the S / N ratio including the crosstalk is improved as the number of repetitions is increased and converges to 11.8 dB, which is improved by about 1 dB from the value when there is no repetition.
　上述したように、本実施形態の光伝送装置および光伝送方法によれば、受信信号の信号品質が最低であるコアにおける号品質を最大化することができる。その結果、コア間で生じる受信信号の信号品質の不均一を縮小し、コア多重された光信号全体としてのクロストークの影響を低減することが可能となる。 As described above, according to the optical transmission device and the optical transmission method of the present embodiment, the signal quality in the core having the lowest signal quality of the received signal can be maximized. As a result, it is possible to reduce the non-uniformity of the signal quality of the reception signal generated between the cores and reduce the influence of crosstalk as the entire core-multiplexed optical signal.
　〔第３の実施形態〕
　次に、本発明の第３の実施形態について説明する。図６は、本実施形態による光伝送装置３００を用いた光伝送システム２０００の構成を示すブロック図である。 [Third Embodiment]
Next, a third embodiment of the present invention will be described. FIG. 6 is a block diagram illustrating a configuration of an optical transmission system 2000 using the optical transmission apparatus 300 according to the present embodiment.
　光伝送システム２０００は、光伝送装置３００と、複数の光伝送路５０、複数の光送信装置２２０、および複数の光受信装置２３０とを有する。複数の光送信装置２２０は、複数の光信号を複数の光強度設定部１１０に送出する。複数の光受信装置２３０は、複数の光伝送路５０を通過した後の複数の光信号を受光する。 The optical transmission system 2000 includes an optical transmission device 300, a plurality of optical transmission paths 50, a plurality of optical transmission devices 220, and a plurality of optical reception devices 230. The plurality of optical transmission devices 220 transmit the plurality of optical signals to the plurality of light intensity setting units 110. The plurality of optical receiving devices 230 receive the plurality of optical signals after passing through the plurality of optical transmission paths 50.
　光伝送装置３００は、複数の光強度設定部１１０と、それぞれの光強度設定部１１０を制御する光強度制御部１２０を有する。光強度設定部１１０は、複数の光伝送路５０にそれぞれ入力する入力光信号の光強度を制御し、所定の入力光強度に設定する。 The optical transmission device 300 includes a plurality of light intensity setting units 110 and a light intensity control unit 120 that controls each of the light intensity setting units 110. The light intensity setting unit 110 controls the light intensity of the input optical signal that is input to each of the plurality of optical transmission lines 50, and sets it to a predetermined input light intensity.
　光強度制御部１２０は、入力光強度を複数の光伝送路５０ごとにそれぞれ決定し、決定した入力光強度に基づいて複数の光強度設定部１１０を制御する。このとき、光強度制御部１２０は複数の光伝送路５０をそれぞれ通過した後の各光信号の信号品質に関する情報に基づいて、複数の光伝送路５０の少なくとも一の光伝送路に対する入力光強度を決定する。 The light intensity control unit 120 determines the input light intensity for each of the plurality of optical transmission paths 50, and controls the plurality of light intensity setting units 110 based on the determined input light intensity. At this time, the light intensity control unit 120 inputs the input light intensity with respect to at least one of the plurality of optical transmission paths 50 based on the information on the signal quality of each optical signal after passing through the plurality of optical transmission paths 50 respectively. To decide.
　ここまでの構成は第１の実施形態の光伝送装置１００と同様である。本実施形態による光伝送装置３００は、信号品質モニタ部３１０をさらに有する。信号品質モニタ部３１０は複数の光伝送路５０の終端側に配置される。そして、複数の光伝送路５０をそれぞれ通過した後の各光信号を検出して信号品質モニタ値を算出し、このときの信号品質モニタ値を信号品質に関する情報として光強度制御部１２０に送出する。 The configuration so far is the same as that of the optical transmission apparatus 100 of the first embodiment. The optical transmission apparatus 300 according to the present embodiment further includes a signal quality monitor unit 310. The signal quality monitor unit 310 is disposed on the terminal end side of the plurality of optical transmission lines 50. Then, each optical signal after passing through each of the plurality of optical transmission lines 50 is detected to calculate a signal quality monitor value, and the signal quality monitor value at this time is sent to the light intensity control unit 120 as information on the signal quality. .
　光伝送装置３００は、信号品質推定部２１０に替えて信号品質モニタ部３１０を備えた構成とした点において、第２の実施形態による光伝送装置２００と異なる。 The optical transmission device 300 is different from the optical transmission device 200 according to the second embodiment in that a signal quality monitoring unit 310 is provided instead of the signal quality estimation unit 210.
　本実施形態による光伝送装置３００によれば、マルチコアファイバ５００の各コアについて、光伝送時における雑音光強度などのパラメータをあらかじめ測定する必要はなくなる。したがって、簡易な制御フローによって、信号品質が最低であるコアにおける受信信号の信号品質を最大化することができる。その結果、複数の光伝送路５０を用いた光伝送システムの特性を最適化することが可能になる。 According to the optical transmission apparatus 300 according to the present embodiment, it is not necessary to previously measure parameters such as noise light intensity during optical transmission for each core of the multi-core fiber 500. Therefore, the signal quality of the received signal in the core having the lowest signal quality can be maximized by a simple control flow. As a result, it is possible to optimize the characteristics of an optical transmission system using a plurality of optical transmission paths 50.
　信号品質モニタ部３１０は、図６に示すように、光受信装置２３０による受信信号の信号品質をそれぞれモニタし、信号品質モニタ値を算出する構成とすることができる。信号品質モニタ値としては、例えば、信号の誤り訂正前後のビット誤り率または誤り訂正前のビット誤り率のＦＥＣ（Ｆｏｒｗａｒｄ　Ｅｒｒｏｒ　Ｃｏｒｒｅｃｔｉｏｎ：前方誤り訂正）リミットからのマージンなどを用いることができる。また、ＥＶＭ（Ｅｒｒｏｒ　Ｖｅｃｔｏｒ　Ｍａｇｎｉｔｕｄｅ）に代表される信号点の広がりなどを用いることができる。 As shown in FIG. 6, the signal quality monitoring unit 310 can be configured to monitor the signal quality of the received signal by the optical receiving device 230 and calculate the signal quality monitor value. As the signal quality monitor value, for example, a bit error rate before and after error correction of a signal or a margin from an FEC (Forward Error Correction) limit of a bit error rate before error correction can be used. Further, the spread of signal points represented by EVM (Error Vector Magnet) can be used.
　光強度制御部１２０は、信号品質モニタ部３１０から受け取った信号品質モニタ値に基づいて、受信信号の信号品質が最も良好であるコアを選択し、そのときの入力光信号の光強度の設定値を低減する。または、受信信号の信号品質が最も低いコアを選択し、そのときの入力光信号の光強度の設定値を増加する。このような処理を繰り返すことによって、各コアにおける入力光強度を制御し、信号品質が最も低いコアにおける受信信号の信号品質を最大化することができる。このとき、各コアにおいて信号品質が光強度に対して単調に増加する範囲内で入力光強度の制御を行う。このようにして決定した入力光強度に基づいて、光強度制御部１２０は光強度設定部１１０を制御し、各コアにそれぞれ入力する入力光信号の光強度を調整する。 The light intensity control unit 120 selects the core having the best signal quality of the received signal based on the signal quality monitor value received from the signal quality monitor unit 310, and the set value of the light intensity of the input optical signal at that time Reduce. Alternatively, the core having the lowest signal quality of the received signal is selected, and the set value of the light intensity of the input optical signal at that time is increased. By repeating such processing, the input light intensity in each core can be controlled, and the signal quality of the received signal in the core having the lowest signal quality can be maximized. At this time, the input light intensity is controlled within a range where the signal quality monotonously increases with respect to the light intensity in each core. Based on the input light intensity determined in this way, the light intensity control unit 120 controls the light intensity setting unit 110 to adjust the light intensity of the input optical signal input to each core.
　以上説明したように、本実施形態による光伝送装置３００によれば、マルチコアファイバを用いた光伝送システム２０００において、コア間における受信信号の信号品質の不均一性を低減し、信号品質が最も低いコアの信号品質を最大化することが可能となる。 As described above, according to the optical transmission device 300 according to the present embodiment, in the optical transmission system 2000 using a multi-core fiber, the non-uniformity of the signal quality of the received signal between the cores is reduced, and the signal quality is the lowest. It becomes possible to maximize the signal quality of the core.
　〔第４の実施形態〕
　次に、本発明の第４の実施形態について説明する。図７は、本実施形態による光伝送装置４００を用いた光伝送システム３０００の構成を示すブロック図である。 [Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described. FIG. 7 is a block diagram showing a configuration of an optical transmission system 3000 using the optical transmission apparatus 400 according to the present embodiment.
　光伝送システム３０００は、光伝送装置４００と、複数の光伝送路５０、複数の光送信装置２２０、および複数の光受信装置２３０とを有する。複数の光送信装置２２０は、複数の光信号を複数の光強度設定部１１０に送出する。複数の光受信装置２３０は、複数の光伝送路５０を通過した後の複数の光信号を受光する。 The optical transmission system 3000 includes an optical transmission device 400, a plurality of optical transmission paths 50, a plurality of optical transmission devices 220, and a plurality of optical reception devices 230. The plurality of optical transmission devices 220 transmit the plurality of optical signals to the plurality of light intensity setting units 110. The plurality of optical receiving devices 230 receive the plurality of optical signals after passing through the plurality of optical transmission paths 50.
　光伝送装置４００は、複数の光強度設定部１１０と、それぞれの光強度設定部１１０を制御する光強度制御部１２０を有する。光強度設定部１１０は、複数の光伝送路５０にそれぞれ入力する入力光信号の光強度を制御し、所定の入力光強度に設定する。 The optical transmission device 400 includes a plurality of light intensity setting units 110 and a light intensity control unit 120 that controls each of the light intensity setting units 110. The light intensity setting unit 110 controls the light intensity of the input optical signal that is input to each of the plurality of optical transmission lines 50, and sets it to a predetermined input light intensity.
　光強度制御部１２０は、入力光強度を複数の光伝送路５０ごとにそれぞれ決定し、決定した入力光強度に基づいて複数の光強度設定部１１０を制御する。このとき、複数の光伝送路５０をそれぞれ通過した後の各光信号の信号品質に関する情報に基づいて、複数の光伝送路５０の少なくとも一の光伝送路に対する入力光強度を決定する。 The light intensity control unit 120 determines the input light intensity for each of the plurality of optical transmission paths 50, and controls the plurality of light intensity setting units 110 based on the determined input light intensity. At this time, the input light intensity for at least one of the plurality of optical transmission paths 50 is determined based on information on the signal quality of each optical signal after passing through each of the plurality of optical transmission paths 50.
　ここまでの構成は第１の実施形態の光伝送装置１００と同様である。本実施形態による光伝送装置４００は、複数の光伝送路５０の終端側に、複数の終端側光強度設定部４１０および終端側光強度制御部４２０をさらに有する。終端側光強度設定部４１０は、複数の光伝送路５０の終端から出力する出力光信号の光強度をそれぞれ制御し、所定の出力光強度に設定する。終端側光強度制御部４２０は、この出力光強度を入力光強度に応じて複数の光伝送路５０ごとにそれぞれ決定し、決定した出力光強度に基づいて複数の終端側光強度設定部４１０を制御する。 The configuration so far is the same as that of the optical transmission apparatus 100 of the first embodiment. The optical transmission apparatus 400 according to the present embodiment further includes a plurality of termination side light intensity setting units 410 and a termination side light intensity control unit 420 on the termination side of the plurality of optical transmission lines 50. The termination side light intensity setting unit 410 controls the light intensity of the output optical signals output from the terminations of the plurality of optical transmission lines 50, respectively, and sets it to a predetermined output light intensity. The termination side light intensity control unit 420 determines the output light intensity for each of the plurality of optical transmission paths 50 according to the input light intensity, and sets the plurality of termination side light intensity setting units 410 based on the determined output light intensity. Control.
　このように、本実施形態の光伝送装置４００は図７に示すように、複数の光伝送路５０を含むマルチコアファイバ５００の始端に光強度設定部１１０を備える。光強度設定部１１０は、光強度制御部１２０の制御により各コアにおける入力光強度を設定する。光伝送装置４００はさらに、マルチコアファイバ５００の終端にも終端側光強度設定部４１０を備える。終端側光強度設定部４１０は、終端側光強度制御部４２０の制御により各コアにおける出力光強度を設定する。このとき、終端側光強度制御部４２０は各コアにおいて、始端の光強度設定部１１０および終端の終端側光強度設定部４１０における光強度の変化量の合計が一定となるように、出力光強度を決定することができる。 As described above, the optical transmission apparatus 400 according to the present embodiment includes the light intensity setting unit 110 at the start end of the multi-core fiber 500 including the plurality of optical transmission paths 50 as illustrated in FIG. The light intensity setting unit 110 sets the input light intensity in each core under the control of the light intensity control unit 120. The optical transmission device 400 further includes a termination-side light intensity setting unit 410 at the termination of the multi-core fiber 500. The termination side light intensity setting unit 410 sets the output light intensity in each core under the control of the termination side light intensity control unit 420. At this time, the termination-side light intensity control unit 420 outputs the output light intensity so that the total amount of change in the light intensity at the start-end light intensity setting unit 110 and the termination-end light intensity setting unit 410 is constant in each core. Can be determined.
　このような構成とすることにより、マルチコアファイバ５００の始端において入力光強度を制御することとした場合に、マルチコアファイバ５００の終端に接続される光受信装置等の機器に入力する光強度が変化することを回避することができる。その結果、マルチコアファイバ５００の終端に接続される機器の安定した動作が可能となる。 With such a configuration, when the input light intensity is controlled at the start end of the multi-core fiber 500, the light intensity input to a device such as an optical receiver connected to the end of the multi-core fiber 500 changes. You can avoid that. As a result, stable operation of the device connected to the end of the multi-core fiber 500 is possible.
　次に、光伝送装置４００の動作について、さらに詳細に説明する。 Next, the operation of the optical transmission apparatus 400 will be described in more detail.
　光強度制御部１２０は、第２の実施形態または第３の実施形態と同様に、信号品質推定部または信号品質モニタ部からの情報に基づいて、信号品質が最も低いコアにおける受信信号の信号品質が最大となるように入力光強度を設定する。 Similar to the second or third embodiment, the light intensity control unit 120 determines the signal quality of the received signal in the core with the lowest signal quality based on information from the signal quality estimation unit or the signal quality monitoring unit. The input light intensity is set so that becomes the maximum.
　光強度制御部１２０によって制御され、光強度設定部１１０に設定される各コアの入力光強度の設定値は、マルチコアファイバ５００の終端側に配置された終端側光強度制御部４２０に送出される。終端側光強度制御部４２０は各コア毎に、光強度設定部１１０の入力から終端側光強度設定部４１０の出力に至るまでの光学損失が一定となるように制御を行う。具体的には例えば、光強度制御部１２０が光強度設定部１１２における入力光強度の設定値を１ｄＢだけ下げるように制御したとする。この場合、終端側光強度制御部４２０は光強度制御部１２０から取得する入力光強度の設定値に基づいて、対応する終端側光強度設定部４１２の設定値を１ｄＢだけ上げるように制御する。なお、光強度設定部１１０と終端側光強度設定部４１０における光学損失の合計が、各コア毎に所定の値となるように予め設定しておくことができる。 The set value of the input light intensity of each core controlled by the light intensity control unit 120 and set in the light intensity setting unit 110 is sent to the termination-side light intensity control unit 420 disposed on the termination side of the multi-core fiber 500. . The termination side light intensity control unit 420 performs control so that the optical loss from the input of the light intensity setting unit 110 to the output of the termination side light intensity setting unit 410 is constant for each core. Specifically, for example, it is assumed that the light intensity control unit 120 performs control so that the set value of the input light intensity in the light intensity setting unit 112 is decreased by 1 dB. In this case, the termination-side light intensity control unit 420 performs control to increase the setting value of the corresponding termination-side light intensity setting unit 412 by 1 dB based on the set value of the input light intensity acquired from the light intensity control unit 120. Note that the total optical loss in the light intensity setting unit 110 and the termination side light intensity setting unit 410 can be set in advance so as to be a predetermined value for each core.
　以上説明したように、本実施形態の光伝送装置４００によれば、マルチコアファイバの終端に接続される光受信装置等の機器に入力する光信号の光強度を変化させることなく、マルチコアファイバの始端で設定される入力光強度を制御することが可能になる。その結果、光受信装置等の動作に影響を及ぼすことなく、光伝送システムの特性を最適化することができる。 As described above, according to the optical transmission device 400 of the present embodiment, the start end of the multicore fiber can be obtained without changing the light intensity of the optical signal input to a device such as an optical receiver connected to the end of the multicore fiber. It becomes possible to control the input light intensity set by. As a result, the characteristics of the optical transmission system can be optimized without affecting the operation of the optical receiver or the like.
　上述した実施形態においては、入力光強度を調整する光強度設定部を、光伝送路の光送信装置側に配置した構成について説明した。しかし、これに限らず、光伝送路の途中に光アンプを配置するマルチコアファイバを用いた光伝送システムに本実施形態の光伝送装置を用いる場合には、中継地点に光強度設定部を配置した構成とすることができる。このような構成とした場合であっても、上記実施形態と同様の効果が得られる。 In the above-described embodiment, the configuration in which the light intensity setting unit for adjusting the input light intensity is arranged on the optical transmission device side of the optical transmission path has been described. However, the present invention is not limited to this, and when the optical transmission device of this embodiment is used in an optical transmission system using a multi-core fiber in which an optical amplifier is arranged in the middle of an optical transmission line, a light intensity setting unit is arranged at a relay point. It can be configured. Even if it is a case where it is such a structure, the effect similar to the said embodiment is acquired.
　本発明は上記実施形態に限定されることなく、特許請求の範囲に記載した発明の範囲内で、種々の変形が可能であり、それらも本発明の範囲内に含まれるものであることはいうまでもない。 The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention described in the claims, and it is also included within the scope of the present invention. Not too long.
　この出願は、２０１２年５月２９日に出願された日本出願特願２０１２－１２２０８５を基礎とする優先権を主張し、その開示の全てをここに取り込む。 This application claims priority based on Japanese Patent Application No. 2012-122085 filed on May 29, 2012, the entire disclosure of which is incorporated herein.
　１０００、２０００、３０００　　光伝送システム
　１００、２００、３００、４００　　光伝送装置
　１１０、１１１～１１７　　光強度設定部
　１２０　　光強度制御部
　２１０　　信号品質推定部
　２２０、２２１～２２７　　光送信装置
　２３０、２３１～２３７　　光受信装置
　３１０　　信号品質モニタ部
　４１０　　終端側光強度設定部
　４２０　　終端側光強度制御部
　５００　　マルチコアファイバ
　６００　　関連するマルチコアファイバ
　６１０　　コア
　６２０　　クラッド
　１０　　入力光信号
　５０　　光伝送路
　５１～コア５７　　コア 1000, 2000, 3000 Optical transmission system 100, 200, 300, 400 Optical transmission device 110, 111-117 Optical intensity setting unit 120 Optical intensity control unit 210 Signal quality estimation unit 220, 221-227 Optical transmission device 230, 231-237 Optical receiver 310 Signal quality monitor unit 410 Termination side light intensity setting unit 420 Termination side light intensity control unit 500 Multicore fiber 600 Related multicore fiber 610 Core 620 Cladding 10 Input optical signal 50 Optical transmission line 51 to Core 57 Core

Claims (10)

  1. 複数の光伝送路にそれぞれ入力する入力光信号の光強度を制御し、所定の入力光強度に設定する複数の光強度設定手段と、
    　前記入力光強度を前記複数の光伝送路ごとにそれぞれ決定し、決定した入力光強度に基づいて前記複数の光強度設定手段を制御する光強度制御手段、を有し、
    　前記光強度制御手段は、前記複数の光伝送路をそれぞれ通過した後の各光信号の信号品質に関する情報に基づいて、前記複数の光伝送路の少なくとも一の光伝送路に対する前記入力光強度を決定する
    　光伝送装置。     A plurality of light intensity setting means for controlling the light intensity of the input optical signal respectively input to the plurality of optical transmission paths and setting the predetermined input light intensity;
    Light intensity control means for determining the input light intensity for each of the plurality of optical transmission paths, and controlling the plurality of light intensity setting means based on the determined input light intensity,
    The light intensity control means determines the input light intensity with respect to at least one optical transmission path of the plurality of optical transmission paths based on information on signal quality of each optical signal after passing through the plurality of optical transmission paths. Determine optical transmission equipment.
  2. 請求項１に記載した光伝送装置において、
    　前記光強度制御手段は、前記信号品質に関する情報を用いて、前記複数の光伝送路の中から前記信号品質が最高である第１の光伝送路を選択し、前記第１の光伝送路に対する入力光信号の光強度の設定値を低減し、低減した後の光強度を前記第１の光伝送路に対する前記入力光強度に決定する
    　光伝送装置。     The optical transmission device according to claim 1,
    The light intensity control means selects the first optical transmission line having the highest signal quality from the plurality of optical transmission lines using the information on the signal quality, and selects the first optical transmission line with respect to the first optical transmission line. An optical transmission device that reduces a set value of the optical intensity of an input optical signal and determines the optical intensity after the reduction as the input optical intensity for the first optical transmission line.
  3. 請求項１または２に記載した光伝送装置において、
    　前記光強度制御手段は、前記信号品質に関する情報を用いて、前記複数の光伝送路の中から前記信号品質が最低である第２の光伝送路を選択し、前記第２の光伝送路に対する入力光信号の光強度の設定値を増加し、増加した後の光強度を前記第２の光伝送路に対する前記入力光強度に決定する
    　光伝送装置。     In the optical transmission device according to claim 1 or 2,
    The light intensity control means selects a second optical transmission line having the lowest signal quality from the plurality of optical transmission lines using the information on the signal quality, and selects the second optical transmission line with respect to the second optical transmission line. An optical transmission device that increases a set value of optical intensity of an input optical signal and determines the optical intensity after the increase as the input optical intensity for the second optical transmission line.
  4. 請求項３に記載した光伝送装置において、
    　前記光強度制御手段は、前記信号品質が前記光強度に対して単調に増加する範囲内で、前記光強度の設定値を増加する動作を行う
    　光伝送装置。     In the optical transmission device according to claim 3,
    The optical intensity control unit performs an operation of increasing the set value of the optical intensity within a range where the signal quality monotonously increases with respect to the optical intensity.
  5. 請求項１から４のいずれか一項に記載した光伝送装置において、
    　信号品質推定手段をさらに有し、
    　前記信号品質推定手段は、少なくとも前記入力光信号の光強度の設定値と、前記複数の光伝送路間のクロストークに関する情報と、雑音光強度に関する情報とから、前記信号品質に関する情報としての信号品質推定値を算出し、前記信号品質推定値を前記光強度制御手段に送出する
    　光伝送装置。     In the optical transmission device according to any one of claims 1 to 4,
    A signal quality estimating unit;
    The signal quality estimation means includes at least a set value of the optical intensity of the input optical signal, information on crosstalk between the plurality of optical transmission lines, and information on noise light intensity, as a signal as information on the signal quality An optical transmission apparatus that calculates a quality estimated value and sends the signal quality estimated value to the light intensity control means.
  6. 請求項１から４のいずれか一項に記載した光伝送装置において、
    　前記複数の光伝送路の終端側に配置される信号品質モニタ手段をさらに有し、
    　前記信号品質モニタ手段は、前記複数の光伝送路をそれぞれ通過した後の各光信号を検出して信号品質モニタ値を算出し、前記信号品質モニタ値を前記信号品質に関する情報として前記光強度制御手段に送出する
    　光伝送装置。     In the optical transmission device according to any one of claims 1 to 4,
    Further comprising signal quality monitoring means arranged on the terminal side of the plurality of optical transmission lines,
    The signal quality monitoring means detects each optical signal after passing through each of the plurality of optical transmission lines, calculates a signal quality monitor value, and uses the signal quality monitor value as information on the signal quality to control the light intensity Optical transmission device to send to means.
  7. 請求項１から６のいずれか一項に記載した光伝送装置において、
    　前記複数の光伝送路の終端側に、複数の終端側光強度設定手段と、終端側光強度制御手段をさらに有し、
    　前記終端側光強度設定手段は、前記複数の光伝送路の終端から出力する出力光信号の光強度をそれぞれ制御して所定の出力光強度に設定し、
    　前記終端側光強度制御手段は、前記出力光強度を、前記入力光強度に応じて前記複数の光伝送路ごとにそれぞれ決定し、決定した出力光強度に基づいて前記複数の終端側光強度設定手段を制御する
    　光伝送装置。     In the optical transmission device according to any one of claims 1 to 6,
    A plurality of termination side light intensity setting means and termination side light intensity control means on the termination side of the plurality of optical transmission lines;
    The termination side light intensity setting means controls the light intensity of the output optical signal output from the terminations of the plurality of optical transmission lines, respectively, and sets it to a predetermined output light intensity,
    The termination-side light intensity control means determines the output light intensity for each of the plurality of optical transmission paths according to the input light intensity, and sets the plurality of termination-side light intensity based on the determined output light intensity. An optical transmission device that controls the means.
  8. 請求項１から７のいずれか一項に記載した光伝送装置と、複数の光伝送路と、複数の光送信装置と、複数の光受信装置、とを有し、
    　前記複数の光送信装置は、複数の光信号を前記複数の光強度設定手段に送出し、
    　前記複数の光受信装置は、前記複数の光伝送路を通過した後の前記複数の光信号を受光する
    　光伝送システム。     The optical transmission device according to any one of claims 1 to 7, a plurality of optical transmission paths, a plurality of optical transmission devices, and a plurality of optical reception devices,
    The plurality of optical transmission devices send a plurality of optical signals to the plurality of light intensity setting means,
    The plurality of optical receivers receive the plurality of optical signals after passing through the plurality of optical transmission lines.
  9. 複数の光伝送路にそれぞれ入力する入力光信号の光強度を制御して所定の入力光強度に設定し、
    　前記複数の光伝送路をそれぞれ通過した後の各光信号の信号品質に関する情報を取得し、
    　前記信号品質に関する情報に基づいて、前記複数の光伝送路の少なくとも一の光伝送路に対する前記入力光強度を決定し、
    　決定した入力光強度に基づいて前記入力光信号の光強度を制御する
    　光伝送方法。     By controlling the light intensity of the input optical signal that is input to each of the plurality of optical transmission lines, it is set to a predetermined input light intensity,
    Obtain information on the signal quality of each optical signal after passing through each of the plurality of optical transmission lines,
    Determining the input light intensity for at least one of the plurality of optical transmission lines based on the information on the signal quality;
    An optical transmission method for controlling the light intensity of the input optical signal based on the determined input light intensity.
  10. 請求項９に記載した光伝送方法において、
    　前記信号品質に関する情報を用いて、前記複数の光伝送路の中から前記信号品質が最高である第１の光伝送路を選択し、
    　前記第１の光伝送路に対する入力光信号の光強度の設定値を低減し、低減した後の光強度を前記第１の光伝送路に対する前記入力光強度に決定し、
    　前記信号品質に関する情報を用いて、前記複数の光伝送路の中から前記信号品質が最低である第２の光伝送路を選択し、前記第２の光伝送路に対する入力光信号の光強度の設定値を増加し、増加した後の光強度を前記第２の光伝送路に対する前記入力光強度に決定する
    　光伝送方法。     The optical transmission method according to claim 9,
    Using the information on the signal quality, the first optical transmission line having the highest signal quality is selected from the plurality of optical transmission lines,
    Reducing the set value of the light intensity of the input optical signal for the first optical transmission line, determining the light intensity after the reduction to the input light intensity for the first optical transmission line;
    Using the information related to the signal quality, the second optical transmission line having the lowest signal quality is selected from the plurality of optical transmission lines, and the light intensity of the input optical signal with respect to the second optical transmission line is selected. An optical transmission method in which a set value is increased and an optical intensity after the increase is determined as the input optical intensity with respect to the second optical transmission line.
PCT/JP2013/003178 2012-05-29 2013-05-20 Optical transmission device, optical transmission system, and optical transmission method WO2013179604A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2012122085 2012-05-29
JP2012-122085 2012-05-29

Publications (1)

Publication Number Publication Date
WO2013179604A1 true WO2013179604A1 (en) 2013-12-05

Family

ID=49672831

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2013/003178 WO2013179604A1 (en) 2012-05-29 2013-05-20 Optical transmission device, optical transmission system, and optical transmission method

Country Status (1)

Country Link
WO (1) WO2013179604A1 (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104202094A (en) * 2014-08-28 2014-12-10 北京邮电大学 Method and device for controlling mode light power
WO2017090616A1 (en) * 2015-11-26 2017-06-01 日本電信電話株式会社 Transmission quality estimation system, transmission quality estimation device, and transmission quality estimation method
WO2018198326A1 (en) * 2017-04-28 2018-11-01 三菱電機株式会社 Optical transmission system
JPWO2018135621A1 (en) * 2017-01-23 2019-11-21 日本電気株式会社 Multi-core optical fiber amplifier and optical amplification method using multi-core optical fiber amplification medium
JP2020120223A (en) * 2019-01-22 2020-08-06 Kddi株式会社 Optical communication system, equalizer thereof, connection device and reception device, and determination device, determination method, and program for attenuation amount given by the equalizer
WO2021172068A1 (en) * 2020-02-27 2021-09-02 日本電気株式会社 Monitoring device, monitoring method, optical amplifyer, and optical transmission system
JPWO2021172069A1 (en) * 2020-02-27 2021-09-02
WO2022038765A1 (en) * 2020-08-21 2022-02-24 日本電信電話株式会社 Optical transport system

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003298526A (en) * 2002-03-29 2003-10-17 Ngk Insulators Ltd Optical communication system, optical communication method, and optical transmission medium
JP2010124266A (en) * 2008-11-20 2010-06-03 Nippon Telegr & Teleph Corp <Ntt> Optical network system
JP2012019264A (en) * 2010-07-06 2012-01-26 Hitachi Ltd Communication system and communication device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003298526A (en) * 2002-03-29 2003-10-17 Ngk Insulators Ltd Optical communication system, optical communication method, and optical transmission medium
JP2010124266A (en) * 2008-11-20 2010-06-03 Nippon Telegr & Teleph Corp <Ntt> Optical network system
JP2012019264A (en) * 2010-07-06 2012-01-26 Hitachi Ltd Communication system and communication device

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
K. TAKENAGA ET AL.: "Reduction of Crosstalk by Quasi-Homogeneous Solid Multi-Core Fiber", OSA/OFC/NFOEC 2010 OWK7, 25 March 2010 (2010-03-25), pages 1 - 3 *

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104202094A (en) * 2014-08-28 2014-12-10 北京邮电大学 Method and device for controlling mode light power
WO2017090616A1 (en) * 2015-11-26 2017-06-01 日本電信電話株式会社 Transmission quality estimation system, transmission quality estimation device, and transmission quality estimation method
JPWO2017090616A1 (en) * 2015-11-26 2018-04-05 日本電信電話株式会社 Transmission quality estimation system, transmission quality estimation device, and transmission quality estimation method
EP3367591A4 (en) * 2015-11-26 2019-07-17 Nippon Telegraph and Telephone Corporation Transmission quality estimation system, transmission quality estimation device, and transmission quality estimation method
US10686520B2 (en) 2015-11-26 2020-06-16 Nippon Telegraph And Telephone Corporation Transmission quality estimation system, transmission quality estimation device, and transmission quality estimation method
US11398711B2 (en) 2017-01-23 2022-07-26 Nec Corporation Multicore optical fiber amplifier and optical amplification method using multicore optical fiber amplification medium
JPWO2018135621A1 (en) * 2017-01-23 2019-11-21 日本電気株式会社 Multi-core optical fiber amplifier and optical amplification method using multi-core optical fiber amplification medium
JP7188085B2 (en) 2017-01-23 2022-12-13 日本電気株式会社 Multi-core optical fiber amplifier and optical amplification method using multi-core optical fiber amplification medium
WO2018198326A1 (en) * 2017-04-28 2018-11-01 三菱電機株式会社 Optical transmission system
JPWO2018198326A1 (en) * 2017-04-28 2019-11-07 三菱電機株式会社 Optical transmission system
JP2020120223A (en) * 2019-01-22 2020-08-06 Kddi株式会社 Optical communication system, equalizer thereof, connection device and reception device, and determination device, determination method, and program for attenuation amount given by the equalizer
JPWO2021172069A1 (en) * 2020-02-27 2021-09-02
WO2021172069A1 (en) * 2020-02-27 2021-09-02 日本電気株式会社 Monitoring device, monitoring method, and optical transmission system
JPWO2021172068A1 (en) * 2020-02-27 2021-09-02
WO2021172068A1 (en) * 2020-02-27 2021-09-02 日本電気株式会社 Monitoring device, monitoring method, optical amplifyer, and optical transmission system
JP7294518B2 (en) 2020-02-27 2023-06-20 日本電気株式会社 MONITORING DEVICE, MONITORING METHOD, OPTICAL AMPLIFIER, AND OPTICAL TRANSMISSION SYSTEM
JP7294519B2 (en) 2020-02-27 2023-06-20 日本電気株式会社 MONITORING DEVICE, MONITORING METHOD, AND OPTICAL TRANSMISSION SYSTEM
WO2022038765A1 (en) * 2020-08-21 2022-02-24 日本電信電話株式会社 Optical transport system
JP7375941B2 (en) 2020-08-21 2023-11-08 日本電信電話株式会社 optical transmission system

Similar Documents

Publication Publication Date Title
WO2013179604A1 (en) Optical transmission device, optical transmission system, and optical transmission method
US8045852B2 (en) Channel balancing algorithm
JP5557399B2 (en) Spatial division multiplexing apparatus including multi-core fiber and self-homodyne detection method
JP5551825B2 (en) Optical receiver power optimization
US6847788B2 (en) System and method for equalizing transmission characteristics in wavelength division multiplexing optical communication system
US8620156B2 (en) Method and apparatus for performing an automatic power adjustment for an optical signal
US9172475B2 (en) Method and apparatus for equalizing link performance
WO2015052895A1 (en) Light reception apparatus, light transmission system, and light reception method
JP4553556B2 (en) WDM optical signal quality monitoring method and apparatus, and optical transmission system using the same
EP1364478B1 (en) Method and system for handling optical signals
US9037002B2 (en) Pre-emphasis control method and optical transmission system
US20150304035A1 (en) Method of optimizing optical signal quality in an optical communications link, optical network element and optical communications link
EP2974078B1 (en) System control of repeatered optical communications system
EP2641344B1 (en) Multi-stage polarization mode dispersion compensation
US8543007B2 (en) Method and apparatus for broadband mitigation of polarization mode dispersion
US7245421B2 (en) Wavelength-division multiplexing optical communication system
US20060044645A1 (en) Method of operating an optical amplifier and optical amplifier
CN101132239A (en) Estimation apparatus and method for optimum dispersion compensation of long-distance WDM system
US7006278B2 (en) Wavelength-division multiplexing optical transmission system and repeater station therein
WO2013128929A1 (en) Optical transport system and optical transport method
JP6519117B2 (en) Optical transmission apparatus, optical transmission system, and control apparatus for optical transmission system
US11115117B2 (en) Submarine optical communication control device, control method, and non-transitory computer-readable medium
EP2945305B1 (en) Monitoring of optical performance in an optical data transmission network
CN115664516B (en) Optical fiber degradation processing method, optical line amplifier and optical transmission system
JP6931367B2 (en) An optical communication system, an equalizer of the optical communication system, a connecting device and a receiving device, and a determination device, a determination method and a program of the amount of attenuation given by the equalization device.

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 13797698

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 13797698

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: JP