Measurement device, management system, and measurement method

Abstract

A measuring device 10 comprises: a creating unit 15 for creating a table associating a value of repeatedly applied electrical noise and a bit error rate generated when the electrical noise is applied, in an optical transmission / reception module which transmits a bit sequence to itself in a predetermined transmission mode; and an estimating unit 16 which uses the table to estimate by calculation an actual-equipment noise curve for the optical transmission / reception module, uses a theoretical formula of the transmission mode to calculate a theoretical noise curve for the optical transmission / reception module, estimates by calculation an amount of noise of the optical transmission / reception module from a deviation between the actual-equipment noise curve and the theoretical noise curve, and uses the amount of noise to estimate by calculation an optical transmission / reception characteristic of the optical transmission / reception module as an actual-equipment characteristic.

Description

[Technical Field]

[0001] The present invention relates to a measurement device, a management system, and a measurement method. [Background technology]

[0002] Conventionally, there is an optical transceiver module that transmits and receives optical signals using coherent optical transmission technology (see Patent Document 1). Coherent optical transmission technology is a technology that performs optical transmission using polarization multiplexing, and in order to increase communication capacity, it uses technologies such as increasing the baud rate of the symbol rate (= higher speed) and increasing the number of bits (= higher bit rate due to different modulation methods). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 031514 Summary of the Invention [Problem to be solved by the invention]

[0004] When evaluating the transmission and reception characteristics of each transmission mode (each transmission mode corresponding to a combination of baud rate and multi-value) in the above optical transceiver module, it is necessary to measure the optical transmission and reception characteristics (BtoB (Back to Back) transmission and reception characteristics; hereafter referred to as actual device characteristics) of the optical transceiver module using the noise loading method, which adds electrical noise using an optical amplifier and an optical spectrum analyzer.

[0005] However, the noise loading method requires large-scale measurement equipment and is a high-risk operation that uses strong optical power, making it difficult to easily measure the characteristics of the actual device at the installation site of the optical transceiver module (for example, the installation site on the transmitting side).

[0006] Furthermore, the characteristics obtained by the noise loading method are overall characteristics of the actual device that combine factors such as characteristic degradation due to the high multi-value level, noise inherent in the optical transceiver module, and characteristic degradation factors due to manufacturing errors, and therefore it is not possible to analyze each degradation factor separately.

[0007] Furthermore, when the optical transceiver module is applied to a Dense Wavelength Division Multiplexing (DWDM) network that uses optical amplifiers to regenerate and repeat optical signals, the transmission and reception characteristics (hereinafter referred to as transmission characteristics), which are the characteristics of a signal after it has passed through a transmission path, deteriorate due to spontaneous emission noise that occurs when the signal is amplified by the optical amplifier and the nonlinear optical effects of the optical fiber.

[0008] If these transmission characteristics could be measured with high precision, it would be possible to optimize the noise margin (the noise threshold at which errors occur on the receiving side) that takes into account noise in the transmission line, thereby maximizing the performance of the transmission line. However, evaluating the transmission characteristics at the site where the optical transceiver module is installed (the site where the receiver is installed) requires large-scale measurement equipment and is a high-risk operation, just like measuring the characteristics of the actual device.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technique that enables optical transmission and reception characteristics to be easily measured. [Means for solving the problem]

[0010] A measuring device according to one embodiment of the present invention includes a creation unit that creates a table that associates the value of repeatedly applied electrical noise with the bit error rate that occurs when the electrical noise is applied in an optical transceiver module that transmits a bit string addressed to itself in a predetermined transmission mode, and an estimation unit that uses the table to estimate an actual noise curve of the optical transceiver module, calculates a theoretical noise curve of the optical transceiver module using a theoretical formula for the transmission mode, estimates the amount of noise of the optical transceiver module from the deviation between the actual noise curve and the theoretical noise curve, and uses the amount of noise to estimate the optical transmission and reception characteristics of the optical transceiver module as actual characteristics.

[0011] A management system according to one aspect of the present invention is an optical transmission network management system comprising a measurement device for measuring optical transmission and reception characteristics, and a control device for controlling the optical transmission network using the measurement results of the optical transmission and reception characteristics. The measurement device comprises: a creation unit that creates a table that associates values ​​of repeatedly applied electrical noise with the bit error rate generated when the electrical noise is applied to an optical transmission and reception module that transmits a bit string addressed to itself in a predetermined transmission mode; and an estimation unit that uses the table to estimate an actual noise curve of the optical transmission and reception module, calculates a theoretical noise curve of the optical transmission and reception module using a theoretical formula for the transmission mode, estimates the amount of noise of the optical transmission and reception module from a deviation between the actual noise curve and the theoretical noise curve, and estimates the optical transmission and reception characteristics of the optical transmission and reception module as actual characteristics using the noise amount. The control device comprises a control unit that uses the actual characteristics to control the optical output power of the optical transmission and reception module, the gain of an optical amplifier on a transmission path connected to the optical transmission and reception module, the filter bandwidth of the optical amplifier, and the optical attenuation of the optical attenuator.

[0012] A measurement method according to one aspect of the present invention is a method for measuring optical transmission and reception characteristics, in which a measurement device creates a table that associates the value of repeatedly applied electrical noise with the bit error rate that occurs when the electrical noise is applied to an optical transmission and reception module that transmits a bit string to itself in a predetermined transmission mode; estimates an actual noise curve of the optical transmission and reception module using the table; calculates a theoretical noise curve of the optical transmission and reception module using a theoretical formula for the transmission mode; estimates the amount of noise of the optical transmission and reception module from the deviation between the actual noise curve and the theoretical noise curve; and estimates the optical transmission and reception characteristics of the optical transmission and reception module as actual characteristics using the amount of noise. [Effects of the Invention]

[0013] According to the present invention, a technique that allows for easy measurement of optical transmission and reception characteristics can be provided. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram showing the overall configuration of an optical transport network management system. [Figure 2] FIG. 2 is a diagram showing the procedure for measuring the characteristics of an actual device. [Figure 3] FIG. 3 is a diagram showing an example of a noise curve. [Figure 4] FIG. 4 is a diagram showing the overall configuration of the optical transport network management system. [Figure 5] FIG. 5 is a diagram showing a procedure for measuring transmission characteristics. [Figure 6] FIG. 6 is a diagram showing the output tendency of optical output power due to temperature and aging. [Figure 7] FIG. 7 is a diagram illustrating the hardware configuration of the measurement device. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings, the same parts are designated by the same reference numerals and the description thereof will be omitted.

[0016] [Method for measuring actual device characteristics] This section explains how to measure the optical transmission and reception characteristics (actual device characteristics) of an optical transmission and reception module.

[0017] 1 is a diagram showing the overall configuration of an optical transmission network management system 1. The optical transmission network management system (management system, optical transmission system) 1 includes a measurement device 10 that measures actual device characteristics of an optical transmitting and receiving module, an optical transmitting and receiving device 30 that transmits and receives optical signals using the optical transmitting and receiving module, and a control device 80 that controls an optical transmission network that includes the optical transmitting and receiving device 30 and the like using the measurement results of the optical transmission and receiving characteristics.

[0018] (Configuration of optical transmitter / receiver) The optical transmitter / receiver 30 comprises an optical transmitter / receiver module 31 to be measured, and a control interface 32 for inputting and outputting data required for the measurement.

[0019] The optical transceiver module 31 is a coherent module that transmits and receives optical signals using coherent optical transmission technology. Coherent optical transmission technology is a technology that performs optical transmission using polarization multiplexing, and in order to increase communication capacity, the symbol rate is increased to a high baud rate and a high multi-value level. A high baud rate means an increase in the modulation speed per unit time, for example, 32 GBaud, 64 GBaud, or 96 GBaud. A high multi-value level means an increase in the number of bits per unit time depending on the modulation method, for example, QPSK (2 bits), 8 QAM (3 bits), or 16 QAM (4 bits).

[0020] The optical transceiver module 31 includes a control unit 41 that controls the optical transceiver module 31, a processing unit 42 that processes optical signals, and a conversion unit 43 that converts optical signals into electrical signals. The optical transceiver module 31 also includes peripheral devices such as a power supply.

[0021] The control unit 41 includes a transmission mode information memory unit 51 that stores transmission mode information regarding the transmission mode of the optical transmitting and receiving module 31, a transmission parameter memory unit 52 that stores transmission parameters for that transmission mode, a temperature measurement unit 53 that measures the temperature of the optical transmitting and receiving module 31, a temperature adjustment unit 54 that adjusts that temperature, a current and voltage measurement unit 55 that measures the drive current and drive voltage of the optical transmitting and receiving module 31, a current and voltage adjustment unit 56 that adjusts the drive current and drive voltage, and a bit error rate measurement unit 57 that measures the bit error rate (BER) of the optical transmitting and receiving module 31.

[0022] The processing unit 42 includes an electrical noise applying unit 61 that applies electrical noise to the optical transmitting and receiving module 31. The processing unit 42 may also include a bit error rate measuring unit 57 that the control unit 41 includes.

[0023] The conversion unit 43 includes a physical cable interface 71 for connecting an optical cable 100. Here, in order to measure the actual device characteristics of the optical transceiver module 31, both ends of a loopback patch cable are loopback-connected to the cable interface 71.

[0024] (Configuration of measuring device) The measurement device 10 includes a theoretical characteristic DB 11, a transmission mode information storage unit 12, a transmission parameter storage unit 13, a temperature information storage unit 14, a table creation unit 15, an optical transmission and reception characteristic estimation unit 16, a first characteristic information storage unit 17, and a first control interface 18.

[0025] The theoretical characteristics DB 11 has a function of storing the theoretical formula for each transmission mode. A transmission mode is a transmission mode corresponding to a combination of one of a plurality of different baud rates and one of a plurality of different multi-values.

[0026] The transmission mode information storage unit 12 has a function of storing transmission mode information of the transmission modes provided in the optical transmitting and receiving module 31 obtained from the optical transmitting and receiving device 30.

[0027] The transmission parameter storage unit 13 has a function of storing the transmission parameters of the transmission modes provided in the optical transceiver module 31 acquired from the optical transceiver 30 .

[0028] The temperature information storage unit 14 has a function of storing the temperature information of the optical transceiver module 31 acquired from the optical transceiver 30 .

[0029] The table creation unit (creation unit) 15 has a function of acquiring the bit error rate and electrical noise values ​​generated in the optical transceiver module 31 and creating a table of the bit error rate and electrical noise. For example, in the optical transceiver module 31 that transmits a bit string to itself in a predetermined transmission mode (including during provisioning), the table creation unit 15 creates a table of the bit error rate and electrical noise that associates the value of the repeatedly applied electrical noise with the bit error rate that occurred when the electrical noise was applied.

[0030] The table creating unit 15 also has the function of creating a table of bit error rate and temperature, a table of bit error rate and drive current, and a table of bit error rate and drive voltage for the optical transmitting and receiving module 31.

[0031] The optical transmission and reception characteristic estimation unit (estimation unit) 16 has the function of estimating and calculating an actual noise curve of the optical transmission and reception module 31 using a table of bit error rates and electrical noise, calculating a theoretical noise curve of the optical transmission and reception module 31 using a theoretical formula corresponding to the transmission mode of the optical transmission and reception module 31, estimating and calculating the amount of noise of the optical transmission and reception module 31 from the deviation between the actual noise curve and the theoretical noise curve, and using the amount of noise to estimate and calculate the optical transmission and reception characteristics of the optical transmission and reception module 31 as actual characteristics.

[0032] The optical transmission / reception characteristic estimation unit 16 also has a function of repeatedly estimating the actual noise curve and terminating the estimation of the actual noise curve when the error between the past bit error rate and the current bit error rate becomes equal to or less than a threshold value.

[0033] In addition, the optical transmission and reception characteristic estimation unit 16 has the function of estimating and calculating the actual characteristics of the optical transmission and reception module 31 in response to changes in temperature of the optical transmission and reception module 31, changes in the drive voltage of the optical transmission and reception module 31, and changes in the drive voltage of the optical transmission and reception module 31.

[0034] The first characteristic information storage unit 17 has a function of storing the actual device characteristics, temperature characteristics, current characteristics, and voltage characteristics estimated and calculated by the optical transmission and reception characteristics estimation unit 16.

[0035] The first control interface 18 has a function of inputting and outputting data required for measuring the actual device characteristics, temperature characteristics, current characteristics, and voltage characteristics of the optical transceiver module 31 provided in the optical transceiver 30 .

[0036] (Control device configuration) The control device 80 includes a control unit 81 .

[0037] The control unit 81 has the function of controlling the optical output power of the optical transceiver module 31, the gain of the optical amplifier on the transmission path connected to the optical transceiver module 31, the filter bandwidth of the optical amplifier, the optical attenuation amount of the optical attenuator, etc., using the actual characteristics, temperature characteristics, current characteristics, and voltage characteristics of the optical transceiver module 31.

[0038] (Procedure for measuring actual device characteristics) FIG. 2 is a diagram showing the procedure for measuring the characteristics of an actual device.

[0039] Step S101; Considering that there are multiple types of transmission modes, the user stores the theoretical formula for each transmission mode in the theoretical characteristics DB 11. For example, the user stores a theoretical formula for a transmission mode that combines a baud rate of 32 GBaud with a modulation method of 16 QAM, a theoretical formula for a transmission mode that combines a baud rate of 64 GBaud with a modulation method of QPSK, and a theoretical formula for a transmission mode that combines a baud rate of 64 GBaud with a modulation method of 16 QAM.

[0040] Step S102; Next, in the measurement device 10, the first control interface 18 acquires transmission mode information (e.g., baud rate value, modulation method type), transmission parameters (e.g., TxOSNR value), and temperature information of the optical transceiver module 31 from the optical transceiver module 31 inserted in the optical transceiver 30. The first control interface 18 stores the transmission mode information in the transmission mode information storage unit 12, stores the transmission parameters in the transmission parameter storage unit 13, and stores the temperature information in the temperature information storage unit 14.

[0041] Step S103; Next, the user loops back a patch cable to the cable interface 71 of the optical transmitting and receiving module 31. While the optical transmitting and receiving module 31 is transmitting and receiving a bit string addressed to the user in a predetermined mode, the user applies electrical noise to the optical transmitting and receiving module 31 using the electrical noise application unit 61. The bit error rate measurement unit 57 measures the bit error rate generated in the optical transmitting and receiving module 31. The bit error rate measurement unit 57 measures the bit error rate each time electrical noise is applied to the optical transmitting and receiving module 31. In the measurement device 10, the table creation unit 15 acquires the bit error rate values ​​and electrical noise values ​​from the optical transmitting and receiving device 30, and creates a table of bit error rates and electrical noise that associates them with each other.

[0042] Step S104; Next, the optical transmission and reception characteristics estimator 16 uses a table of bit error rates and electrical noise to estimate and calculate an actual noise curve for the optical transmission and reception module 31. For example, the optical transmission and reception characteristics estimator 16 calculates the OSNR (Optical Signal to Noise Ratio) based on the electrical noise values ​​and transmission parameters in the table, and plots the OSNR value and the bit error rate in the table on a graph with OSNR on the horizontal axis and BER on the vertical axis. The curve that fits the multiple plotted points is then taken as the actual noise curve. An example of an actual noise curve is shown in Figure 3. N1 is the actual noise curve in QPSK transmission mode. N2 is the actual noise curve in 16QAM transmission mode.

[0043] Next, the optical transmission and reception characteristics estimator 16 reads the transmission mode of the optical transmission and reception module 31 from the transmission mode information storage unit 12 and obtains the theoretical formula corresponding to that transmission mode from the theoretical characteristics DB 11. The optical transmission and reception characteristics estimator 16 then calculates the theoretical noise curve for that transmission mode using the theoretical formula. In Figure 3, M1 is the theoretical noise curve for the QPSK transmission mode, and M2 is the theoretical noise curve for the 16QAM transmission mode.

[0044] Then, the optical transmission and reception characteristic estimating unit 16 estimates and calculates the amount of noise in the optical transmission and reception module 31 based on the value (deviation value) obtained by subtracting the theoretical noise curve from the actual noise curve. Thereafter, the optical transmission and reception characteristic estimating unit 16 estimates and calculates the optical transmission and reception characteristics (actual characteristics) of the transmission mode provided in the optical transmission and reception module 31 using the amount of noise.

[0045] Regarding the actual device characteristics, a table that associates the estimated calculated noise amount with the OSNR value may be used as the actual device characteristics as is, or a noise curve corresponding to the noise amount (a curve that follows multiple plot points plotted on a graph of BER and OSNR) may be used as the actual device characteristics, or the value of the noise curve may be divided by the value of the actual device noise curve.

[0046] The procedures of steps S103 to S104 are repeated for the actual device characteristics of one transmission mode. Every time an actual device noise curve is estimated, the error between the previous bit error rate measured in step S103 and the current bit error rate is calculated, and when this error becomes equal to or less than a threshold, the measurement of the actual device characteristics is completed and the estimation of the actual device noise curve is terminated. If the optical transmission and reception module 31 has multiple transmission modes, the optical transmission and reception characteristics estimator 16 estimates and calculates the actual device characteristics for each transmission mode.

[0047] Thereafter, the optical transmission and reception characteristic estimator 16 stores the actual characteristics of the optical transmission and reception module 31 in the first characteristic information storage unit 17. The actual characteristics are the transmission and reception characteristics of the optical signal caused by the internal noise of the optical transmission and reception module 31.

[0048] Step S105; The main cause of noise generated in the optical transceiver module 31 is thermal noise, and the magnitude of the thermal noise depends on the temperature. Therefore, the user uses the temperature adjustment unit 54 to increase or decrease the temperature of the optical transceiver module 31 by a fixed temperature from the current temperature. Each time the temperature is increased or decreased by a fixed temperature, the optical transceiver characteristic estimation unit 16 acquires the bit error rate value measured by the bit error rate measurement unit 57 and the temperature after the increase or decrease, and creates a table of bit error rates and temperatures in which these values ​​are associated with each other. The optical transceiver characteristic estimation unit 16 then uses the table to estimate and calculate the optical transceiver characteristics in response to temperature changes as temperature characteristics, and stores the temperature characteristics in the first characteristic information storage unit 17.

[0049] Step S106; The user also increases or decreases the drive current of the optical transceiver module 31 by a fixed value from the current value using the current / voltage adjuster 56. Each time the current value is increased or decreased by a fixed value, the optical transceiver characteristic estimator 16 acquires the bit error rate value measured by the bit error rate measurer 57 and the current value after the increase or decrease, and creates a table of bit error rates and currents that associates these values ​​with each other. The optical transceiver characteristic estimator 16 then uses this table to estimate and calculate the optical transceiver characteristics in response to current changes as current characteristics, and stores these current characteristics in the first characteristic information storage unit 17.

[0050] Similarly, the optical transmission and reception characteristic estimator 16 estimates and calculates the optical transmission and reception characteristics of the optical transmission and reception module 31 in response to changes in the drive voltage as voltage characteristics, and stores the voltage characteristics in the first characteristic information storage unit 17 .

[0051] So far, the procedure for measuring the characteristics of the actual device has been explained.

[0052] Thereafter, in the control device 80, the control unit 81 controls the optical output power of the optical transceiver module 31, the gain of the optical amplifier on the transmission path connected to the optical transceiver module 31, the filter bandwidth of the optical amplifier, the optical attenuation amount of the optical attenuator, etc., based on the actual characteristics, temperature characteristics, current characteristics, and voltage characteristics of the optical transceiver module 31 stored in the first characteristic information memory unit 17.

[0053] (effect) As described above, according to this embodiment, the measuring device 10 is equipped with: a table creation unit 15 that creates a table that associates the value of repeatedly applied electrical noise with the bit error rate that occurs when the electrical noise is applied, in an optical transceiver module that transmits a bit string to itself in a predetermined transmission mode; and an optical transceiver characteristic estimation unit 16 that uses the table to estimate an actual noise curve of the optical transceiver module, calculates a theoretical noise curve of the optical transceiver module using a theoretical formula for the transmission mode, estimates the amount of noise of the optical transceiver module from the deviation between the actual noise curve and the theoretical noise curve, and estimates the optical transceiver characteristics of the optical transceiver module as actual characteristics using the amount of noise.Therefore, it is possible to easily measure the optical transceiver characteristics (actual characteristics) of an optical transceiver module without using a large-scale measuring device.

[0054] [Method for measuring transmission characteristics] Next, a method for measuring optical transmission and reception characteristics (transmission characteristics) including the transmission path between the transmission and reception modules will be described.

[0055] 4 is a diagram showing the overall configuration of the optical transmission network management system 1. The optical transmitter / receiver 30 on the transmitting side is designated by the symbol A, and the optical transmitter / receiver 30 on the receiving side is designated by the symbol B. The optical transmitter / receiver 30A on the transmitting side and the optical transmitter / receiver 30B on the receiving side are connected by a DWDM network 200 using multistage optical amplifiers.

[0056] (Configuration of measuring device) The measurement device 10 further includes a transmission mode comparison unit 19 , a common mode storage unit 20 , a second characteristic information storage unit 21 , and a second control interface 22 .

[0057] The transmission mode comparison unit (comparison unit) 19 has the function of comparing the transmission modes of the optical transmitting and receiving module 31A on the transmitting side with the transmission modes of the optical transmitting and receiving module 31B on the receiving side, identifying and listing common transmission modes.

[0058] The common mode storage unit 20 has a function of storing the common transmission modes listed by the transmission mode comparison unit 19 .

[0059] The table creation unit 15 has a function of creating a table of bit error rates and electrical noise that associates the value of repeatedly applied electrical noise with the bit error rate that occurs when the electrical noise is applied in the receiving optical transceiver module 31B, which receives a bit string from the transmitting optical transceiver module 31A via the DWDM network 200 in the above-mentioned common transmission mode (including during provisioning).

[0060] The optical transmission and reception characteristic estimation unit 16 has the function of estimating and calculating a transmission noise curve including noise in the DWDM network 200 using a table of bit error rates and electrical noise, calculating theoretical noise curves for each optical transmission and reception module 31A, 31B on the transmitting and receiving sides using the theoretical formula for the common transmission mode, estimating and calculating a comprehensive noise amount that includes the noise amount of the optical transmission and reception modules 31A, 31B on the transmitting and receiving sides and the noise amount of the DWDM network 200 from the deviation between the transmission noise curve and the theoretical noise curve of each optical transmission and reception module 31A, 31B, and using the comprehensive noise amount to estimate and calculate the optical transmission and reception characteristics in the DWDM network 200 as transmission characteristics.

[0061] For example, the optical transmission and reception characteristic estimation unit 16 removes the amount of noise based on the actual characteristics of the optical transmission and reception modules 31A and 31B on the transmitting and receiving sides from the estimated and calculated comprehensive noise amount, and estimates and calculates the transmission characteristics in the DWDM network 200 using the removed amount of noise.

[0062] The optical transmission / reception characteristic estimating unit 16 also has a function of repeatedly estimating and calculating the transmission noise curve, and terminating the calculation of the transmission noise curve when the error between the past bit error rate and the current bit error rate becomes equal to or less than a threshold value.

[0063] In addition, the optical transmission and reception characteristic estimation unit 16 has a function of estimating and calculating the transmission characteristics with respect to temperature changes of the transmitting and receiving optical transmission and reception modules 31A and 31B, changes in the drive voltage of the transmitting and receiving optical transmission and reception modules 31A and 31B, and changes in the drive voltage of the transmitting and receiving optical transmission and reception modules 31A and 31B.

[0064] The second characteristic information storage unit 21 has a function of storing the transmission characteristics, temperature characteristics, current characteristics, and voltage characteristics estimated and calculated by the optical transmission and reception characteristics estimation unit 16.

[0065] The second control interface 22 has a function of inputting and outputting data required for measuring the transmission characteristics, temperature characteristics, current characteristics, and voltage characteristics of the optical transceiver modules 31A and 31B on the transmitting and receiving sides and the DWDM network 200.

[0066] (Configuration of optical transmitter / receiver) The optical transmitters and receivers 30A and 30B on the transmitting and receiving sides have the same configuration as that shown in FIG.

[0067] (Control device configuration) The control device 80 has the same configuration as that shown in FIG.

[0068] (Transmission characteristics measurement procedure) 5 is a diagram showing a procedure for measuring transmission characteristics. The first characteristic information storage unit 17 stores the actual device characteristics, temperature characteristics, current characteristics, and voltage characteristics of the optical transmitting and receiving module 31A on the transmitting side.

[0069] Step S201; In the measurement device 10, the optical transmission and reception characteristic estimation unit 16 acquires the theoretical formula for each transmission mode from the theoretical characteristic DB 11, and acquires the actual characteristics, temperature characteristics, current characteristics, and voltage characteristics of the transmitting-side optical transmission and reception module 31A from the first characteristic information storage unit 17.

[0070] Step S202; Next, the second control interface 22 acquires, from the optical transceiver module 31B inserted in the receiving-side optical transceiver 30B, transmission mode information (e.g., baud rate value, modulation method type), transmission parameters (e.g., TxOSNR value), and temperature information of the optical transceiver module 31B. Thereafter, the second control interface 22 stores the transmission mode information in the transmission mode information storage unit 12, the transmission parameters in the transmission parameter storage unit 13, and the temperature information in the temperature information storage unit 14.

[0071] Step S203; Next, the transmission mode comparison unit 19 compares the transmission mode provided by the optical transceiver module 31A on the transmitting side with the transmission mode provided by the optical transceiver module 31B on the receiving side, identifies the common transmission modes common to the two optical transceiver modules, creates a list, and stores the list in the common mode storage unit 20. The method of comparing the transmission modes provided by two different optical transceiver modules and identifying the similarities and differences between the transmission modes can be realized using any existing method.

[0072] Step S204; Next, the user connects the transmitting optical transceiver module 31A and the receiving optical transceiver module 31B via a DWDM network 200 using multi-stage optical amplifiers. While the receiving optical transceiver module 31B receives a bit string from the transmitting optical transceiver module 31A in the common transmission mode, the user injects electrical noise into the receiving optical transceiver module 31B using the receiving electrical noise injection unit. The receiving bit error rate measurement unit measures the bit error rate of the receiving optical transceiver module 31B. The receiving bit error rate measurement unit measures the bit error rate each time electrical noise is added to the receiving optical transceiver module 31B. In the measurement device 10, the table creation unit 15 acquires the bit error rate value and the electrical noise value from the receiving optical transceiver module 30B and creates a table of the receiving bit error rate and electrical noise in which they are associated with each other.

[0073] Step S205; Next, the optical transmission and reception characteristics estimator 16 uses a table of the bit error rate and electrical noise on the receiving side to estimate and calculate a transmission noise curve for the receiving-side optical transmission and reception module 31B. For example, the optical transmission and reception characteristics estimator 16 calculates the OSNR based on the electrical noise value and transmission parameters in the table, and plots the OSNR value and the bit error rate in the table on a graph with the OSNR on the horizontal axis and the BER on the vertical axis. The curve that fits the multiple plotted points is then taken as the transmission noise curve.

[0074] Next, the optical transmission and reception characteristic estimation unit 16 reads out the transmission mode (common transmission mode) of the receiving-side optical transmission and reception module 31B from the transmission mode information storage unit 12, and calculates the theoretical noise curve of that transmission mode using a theoretical formula corresponding to that common transmission mode.

[0075] Then, based on the value (deviation value) obtained by subtracting the theoretical noise curve from the transmission noise curve, the optical transmission and reception characteristic estimation unit 16 estimates and calculates the comprehensive noise amount that includes the noise amount of the optical transmission and reception modules 31A, 31B on the transmitting and receiving sides and the noise amount caused by the transmission path of the DWDM network 200 (spontaneous emission noise and nonlinear optical effects).

[0076] Thereafter, the optical transmission and reception characteristic estimator 16 calculates the amount of noise of the transmitting optical transmission and reception module 31A from the actual equipment characteristics acquired in step S201 (or uses the amount of noise calculated when estimating the actual equipment characteristics of the transmitting optical transmission and reception module 31A), and further estimates and calculates the amount of noise of the receiving optical transmission and reception module 31B in accordance with the procedure for measuring the actual equipment characteristics.The optical transmission and reception characteristic estimator 16 then estimates and calculates only the amount of noise caused by the transmission path of the DWDM network 200 by removing these two amounts of noise from the above-mentioned comprehensive amount of noise, and estimates and calculates the transmission characteristics of only the DWDM network 200 (the optical transmission and reception characteristics of the transmission modes listed in step S203) as the transmission characteristics using only this amount of noise.

[0077] Regarding the transmission characteristics, a table that associates the estimated noise amount and the OSNR value with each other may be used as the transmission characteristics as is, or a noise curve corresponding to the noise amount (a curve that follows multiple plot points plotted on a graph of BER and OSNR) may be used as the transmission characteristics, or the value of the noise curve divided by the value of the transmission noise curve may be used as the transmission characteristics.

[0078] The procedures of steps S204 to S205 are repeated for the transmission characteristics of one transmission mode. Every time a transmission noise curve is estimated, the error between the previous bit error rate measured in step S204 and the current bit error rate is calculated, and when the error becomes equal to or smaller than a threshold, the measurement of the transmission characteristics is completed and the estimation of the transmission noise curve is terminated. If there are multiple transmission modes in the list, the optical transmission and reception characteristics estimating unit 16 estimates and calculates the transmission characteristics of each transmission mode.

[0079] Thereafter, the optical transmission and reception characteristic estimator 16 stores the transmission characteristic in the second characteristic information storage unit 21. The transmission characteristic is the transmission and reception characteristic of the optical signal caused by noise during transmission in the DWDM network 200.

[0080] Step S206; Next, the optical transmission and reception characteristics estimator 16 compares the comprehensive noise amount estimated in step S205 with the noise estimate calculated by a predetermined transmission line design tool, and corrects the transmission parameters for noise estimation of the transmission line design tool or the comprehensive noise amount based on the comparison result. This makes it possible to obtain an estimate of the noise amount that is closer to the actual measurement when estimating the noise amount for an arbitrary DWDM network.

[0081] For example, there are two correction methods.

[0082] The first method is to correct the transmission parameters of the transmission design tool using the comprehensive noise amount. The comprehensive noise amount is the sum of the noise N1 (internal noise) of the optical transceiver module and the noise N2 (spontaneous emission noise and nonlinear optical effects) caused by the transmission path, and the individual values ​​of each are unknown.

[0083] Therefore, noise N1 is calculated in advance using the electrical noise loading method in a loopback configuration, and noise N2 is obtained by subtracting this noise N1 from the comprehensive noise amount. Next, a transmission design tool is used to calculate noise N2' caused by the transmission path. The noise N2' calculated with the transmission design tool is then compared with the actually measured noise N2, and the transmission parameters set in the transmission design tool (for example, the loss coefficient and dispersion value of the optical fiber, the noise figure of the optical amplifier, etc.) are corrected based on the comparison results.

[0084] The second method is to correct the comprehensive noise amount using the noise estimated by the transmission design tool. The comprehensive noise amount is the sum of the noise N1 (internal noise) of the optical transceiver module and the noise N2 (spontaneous emission noise and nonlinear optical effects) caused by the transmission path, and the individual values ​​of each are unknown.

[0085] Therefore, a transmission design tool is used to determine noise N2 caused by the transmission path, and noise N1 is obtained by subtracting this noise N2 from the comprehensive noise amount. If the transmission conditions change due to changes in the settings or routes of the DWDM network 200, the value of noise 2 will change, but by calculating the value of noise 2 after the change using the transmission design tool, the total amount of noise under various conditions (the sum of noise N1 and noise N2) can be estimated without transmitting an actual signal.

[0086] Step S207; Next, the user uses the temperature adjustment unit on the transmitting side to increase or decrease the temperature of the optical transceiver module 31A on the transmitting side from its current temperature by a fixed temperature, and also uses the temperature adjustment unit on the receiving side to increase or decrease the temperature of the optical transceiver module 31B on the receiving side by a fixed temperature. Each time the temperature is increased or decreased by a fixed temperature, the optical transmission and reception characteristic estimation unit 16 acquires the bit error rate value measured by the bit error rate measurement unit on the receiving side and the temperature after the increase or decrease, and creates a table of bit error rates and temperatures in which these values ​​are associated with each other. The optical transmission and reception characteristic estimation unit 16 then uses the table to estimate and calculate the optical transmission and reception characteristics in response to temperature changes as temperature characteristics, and stores the temperature characteristics in the second characteristic information storage unit 21.

[0087] Step S208; The user also uses the transmitting-side current / voltage adjustment unit to increase or decrease the drive current of the transmitting-side optical transceiver module 31A by a fixed value from the current value, and also uses the receiving-side current / voltage adjustment unit to increase or decrease the drive current of the receiving-side optical transceiver module 31B by a fixed value. Each time the current value is increased or decreased by a fixed value, the optical transmission and reception characteristic estimation unit 16 acquires the bit error rate value measured by the bit error rate measurement unit 57 and the current value after the increase or decrease, and creates a bit error rate / current table that associates these values. The optical transmission and reception characteristic estimation unit 16 then uses the table to estimate and calculate the optical transmission and reception characteristics in response to current changes as current characteristics, and stores the current characteristics in the second characteristic information storage unit 21.

[0088] Similarly, the optical transmission and reception characteristic estimating unit 16 estimates and calculates the optical transmission and reception characteristics of the optical transmission and reception module 31 in response to changes in the drive voltage as voltage characteristics, and stores the voltage characteristics in the second characteristic information storage unit 21.

[0089] So far, the procedure for measuring transmission characteristics has been explained.

[0090] Thereafter, in the control device 80, the control unit 81 controls the optical output power of the optical transmitting and receiving module 31, the gain of the optical amplifiers that make up the DWDM network 200, the filter bandwidth of the optical amplifiers, the optical attenuation amount of the optical attenuator, etc., based on the actual characteristics, temperature characteristics, current characteristics, and voltage characteristics of the optical transmitting and receiving module 31 stored in the first characteristic information memory unit 17, and the transmission characteristics, temperature characteristics, current characteristics, and voltage characteristics stored in the second characteristic information memory unit 21.

[0091] (effect) As described above, according to this embodiment, the measurement device 10 further includes a transmission mode comparison unit 19 that compares the transmission mode of the optical transmitting and receiving module on the transmitting side with the transmission mode of the optical transmitting and receiving module on the receiving side to identify a common transmission mode, and the table creation unit 15 creates a table that associates the value of repeatedly applied electrical noise with the bit error rate that occurs when the electrical noise is applied in the optical transmitting and receiving module on the receiving side that receives the bit string from the optical transmitting and receiving module on the transmitting side via a transmission path in the common transmission mode, and the optical transmission and receiving characteristic estimation unit 16 uses the table to a transmission noise curve including the noise of the transmission path is estimated and calculated using the theoretical formula of the common transmission mode, a theoretical noise curve of each optical transceiver module on the transmitting side and the receiving side is calculated using the theoretical formula of the common transmission mode, a comprehensive noise amount that includes the noise amount of the optical transceiver modules on the transmitting side and the receiving side and the noise amount of the transmission path is estimated and calculated from the deviation between the transmission noise curve and the theoretical noise curve of each optical transceiver module, and the optical transmission and reception characteristics on the transmission path are estimated and calculated as transmission characteristics using the comprehensive noise amount, so that the optical transmission and reception characteristics (transmission characteristics) on the transmission path can be easily measured without using a large-scale measuring device.

[0092] Furthermore, according to this embodiment, the optical transmission and reception characteristics estimator 16 estimates and calculates the transmission characteristics of the transmission path by removing the noise amount based on the actual device characteristics of the optical transmission and reception modules on the transmitting and receiving sides from the comprehensive noise amount, so that the transmission characteristics related to only the transmission path can be accurately measured.

[0093] [Measures to deal with deterioration of optical transceiver modules] So far, we have explained the actual characteristics of the optical transceiver module 31 and the transmission characteristics of the DWDM network 200. We will now discuss degradation of the optical transceiver module 31. Due to high temperatures and aging, the optical transceiver module 31 requires a larger drive current and drive voltage to maintain the desired optical output.

[0094] Therefore, the optical transmission and reception characteristic estimation unit 16 has a function of estimating and calculating the optical output power of the optical transmission and reception module 31 based on the actual characteristics in response to changes in the drive current of the optical transmission and reception module 31 and changes in the drive voltage of the optical transmission and reception module 31, and notifying the resultant value in response to changes in temperature and aging of the optical transmission and reception module 31.

[0095] The optical transmission and reception characteristic estimation unit 16 also has a function of estimating and calculating the optical output power of the transmitting and receiving optical transmission and reception modules 31A, 31B based on the transmission characteristics in response to changes in the drive current of the transmitting and receiving optical transmission and reception modules 31A, 31B and changes in the drive voltage of the transmitting and receiving optical transmission and reception modules 31A, 31B, and in response to changes in temperature and aging of the transmitting and receiving optical transmission and reception modules 31A, 31B, and notifying the result.

[0096] For example, the optical transmission and reception characteristic estimator 16 uses the temperature and current characteristics to estimate and calculate the optical output power T1 of the optical transmission and reception module at the current temperature relative to changes in drive current, as shown in Figure 6, and plots the result on a graph with drive current on the horizontal axis and optical output power on the vertical axis. The optical transmission and reception characteristic estimator 16 also plots optical output power T2 due to temperature rise and aging, and optical output power T3 due to further temperature rise and aging. If the drive current required for the desired optical output power exceeds a threshold, or if the optical output power falls below the threshold, the optical transmission and reception characteristic estimator 16 notifies the control device 80 that the noise immunity of the transmission and reception module has decreased.

[0097] This makes it possible to properly grasp the temperature rise and aging of the optical transceiver module 31, and maintain the optical transmission quality of the optical transmission network at a high level.

[0098] [others] The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the present invention.

[0099] In the above embodiment, the measurement device 10 has been described as a device separate from the optical transceiver 30 and the control device 80, but this device configuration is merely an example. For example, the measurement device 10 may be implemented inside the optical transceiver 30. Similarly, the measurement device 10 may be implemented inside the optical transceiver 30A on the transmitting side, or the measurement device 10 may be implemented inside the optical transceiver 30B on the receiving side. Furthermore, the measurement device 10 may be implemented inside the control device 80.

[0100] The measuring device 10 of the present embodiment described above can be realized, for example, by using a general-purpose computer system including a CPU 901, a memory 902, a storage 903, a communication device 904, an input device 905, and an output device 906, as shown in Fig. 7. The memory 902 and the storage 903 are storage devices. In the computer system, the CPU 901 executes a predetermined program loaded onto the memory 902, thereby realizing each function of the measuring device 10.

[0101] The measurement device 10 may be implemented by one computer, or by multiple computers, or may be a virtual machine implemented on a computer.

[0102] The program for the measurement device 10 can be stored in a computer-readable recording medium such as a HDD, SSD, USB memory, CD, DVD, etc. The program for the measurement device 10 can also be distributed via a communication network. [Explanation of symbols]

[0103] 1: Optical transmission network management system 10: Measuring equipment 11: Theoretical characteristics DB 12: Transmission mode information storage unit 13: Transmission parameter storage unit 14: Temperature information storage section 15: Table creation section 16: Optical transmission and reception characteristic estimation unit 17: First characteristic information storage unit 18: First control interface 19: Transmission mode comparison section 20: Common mode memory unit 21: Second characteristic information storage unit 22: Second control interface 30: Optical transmitter / receiver 31: Optical transceiver module 32: Control interface 41: Control unit 42: Processing section 43: Conversion section 51: Transmission mode information storage unit 52: Transmission parameter storage unit 53:Temperature measurement part 54: Temperature adjustment section 55: Current and voltage measurement section 56: Current / voltage adjustment section 57: Bit error rate measurement unit 61: Electrical noise application unit 71: Cable interface 80: Control device 81: Control unit 100: Optical cable 200: DWDM network 901:CPU 902: Memory 903:Storage 904:Communication equipment 905: Input device 906: Output device

Claims

1. An optical transceiver module that transmits a first bit string to itself in a predetermined transmission mode, comprising: a generator that generates a table that associates values ​​of repeatedly applied electrical noise with bit error rates that occur when the electrical noise is applied; an estimation unit that uses the table to estimate and calculate an actual noise curve of the optical transceiver module that indicates the relationship between the magnitude of electrical noise and the bit error rate, uses a theoretical equation for the transmission mode to calculate a theoretical noise curve of the optical transceiver module that indicates the relationship between the magnitude of electrical noise and the bit error rate, estimates and calculates the amount of noise of the optical transceiver module from a deviation between the actual noise curve and the theoretical noise curve, and uses the noise amount to estimate and calculate, as actual characteristics, optical transmission and reception characteristics of the optical transceiver module that indicate the amount of noise after transmission of the first bit string relative to the amount of noise before transmission; A measuring device comprising:

2. a comparison unit that compares a transmission mode provided in the optical transceiver module on the sending side with a transmission mode provided in the optical transceiver module on the receiving side to identify a common transmission mode; The creation unit a receiving optical transceiver module that receives the second bit string from the transmitting optical transceiver module via a transmission path in the common transmission mode, creating a table that associates values ​​of the repeatedly applied electrical noise with bit error rates that occur when the electrical noise is applied; The estimation unit the measurement device according to claim 1, further comprising: an optical transmission and reception characteristic measuring device for measuring a noise level of the optical transmission and reception module on the transmitting side; an optical transmission and reception characteristic measuring device for measuring a noise level of the optical transmission and reception module on the transmitting side; an optical transmission and reception characteristic measuring device for measuring a noise level of the optical transmission and reception module on the transmitting side;

3. The estimation unit 3. The measuring device according to claim 2, wherein the transmission characteristics of the transmission path are estimated by removing the amount of noise based on the actual device characteristics of the optical transmitting and receiving modules from the comprehensive noise amount.

4. The estimation unit 3. The measuring device according to claim 2, wherein the actual device characteristics or the transmission characteristics are estimated and calculated with respect to a temperature change of the optical transceiver module, a change in the drive voltage of the optical transceiver module, or a change in the drive voltage of the optical transceiver module.

5. The estimation unit 3. The measuring device according to claim 2, wherein the estimation calculation of the actual noise curve is repeatedly performed, and when an error between a past bit error rate and a current bit error rate becomes equal to or less than a threshold, the estimation calculation of the actual noise curve is terminated, and the estimation calculation of the transmission noise curve is repeatedly performed, and when an error between a past bit error rate and a current bit error rate becomes equal to or less than a threshold, the estimation calculation of the transmission noise curve is terminated.

6. The estimation unit The measuring device according to claim 2, wherein the optical output power of the optical transceiver module based on the actual characteristics or the transmission characteristics in response to a change in the drive current of the optical transceiver module or a change in the drive voltage of the optical transceiver module is estimated and calculated in response to temperature changes and aging of the optical transceiver module, and notified.

7. 1. A management system for an optical transmission network comprising a measurement device for measuring optical transmission and reception characteristics, and a control device for controlling an optical transmission network using the measurement results of the optical transmission and reception characteristics, The measuring device is an optical transceiver module that transmits a bit string to itself in a predetermined transmission mode, a generator that generates a table that associates values ​​of repeatedly applied electrical noise with bit error rates that occur when the electrical noise is applied; an estimation unit that uses the table to estimate and calculate an actual noise curve of the optical transceiver module that indicates the relationship between the magnitude of electrical noise and the bit error rate, calculates a theoretical noise curve of the optical transceiver module that indicates the relationship between the magnitude of electrical noise and the bit error rate using the theoretical equation of the transmission mode, estimates and calculates the amount of noise of the optical transceiver module from a deviation between the actual noise curve and the theoretical noise curve, and estimates and calculates, as actual characteristics, optical transmission and reception characteristics of the optical transceiver module that indicate the amount of noise after transmission of the bit string relative to the amount of noise before transmission, using the amount of noise; The control device a control unit for controlling the optical output power of the optical transceiver module, the gain of an optical amplifier on a transmission line connected to the optical transceiver module, the filter bandwidth of the optical amplifier, and the optical attenuation of an optical attenuator using the actual device characteristics; Management system.

8. A measurement method for measuring optical transmission and reception characteristics, comprising: The measuring device In an optical transceiver module that transmits a bit string to itself in a predetermined transmission mode, a table is created that associates values ​​of repeatedly applied electrical noise with bit error rates that occur when the electrical noise is applied; using the table to estimate an actual noise curve of the optical transceiver module that indicates the relationship between the magnitude of electrical noise and the bit error rate, using the theoretical equation for the transmission mode to calculate a theoretical noise curve of the optical transceiver module that indicates the relationship between the magnitude of electrical noise and the bit error rate, estimating the amount of noise of the optical transceiver module from the deviation between the actual noise curve and the theoretical noise curve, and using the noise amount to estimate the optical transmission and reception characteristics of the optical transceiver module that indicate the amount of noise after transmission of the bit string relative to the amount of noise before transmission as actual characteristics; How to perform the measurement.

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