Nonlinear effect suppression link and design method thereof

Abstract

The invention discloses a nonlinear effect suppression link and a design method thereof. Two wavelength converters are adopted in an optical fiber link, and the placement positions of the two wavelength converters and dispersion compensation unit parameters are calculated according to a specific method, so that all-optical nonlinear compensation can be realized on the basis of an original transceiver, and the compensation method mainly considers the wavelength correlation of optical fiber loss, dispersion and nonlinear coefficients. According to the placement position calculation method, correction values of optical fiber loss and nonlinear coefficients need to be calculated according to a wave band where a signal is located and a conversion target wave band, and the placement positions of the two wavelength converters in an optical fiber link are determined on the basis. On the basis of completing the placement position design, a dispersion value needing to be compensated in the wavelength converter is calculated according to the dispersion of the wave band where the signal is located and the dispersion of the conversion target wave band, so that the optimal nonlinear compensation effect is achieved.

Description

Technical Field

[0001] The present application relates to the field of optical communication technology, and in particular to a nonlinear effect suppression link and a design method thereof. Background Art

[0002] When optical signals are transmitted through optical fibers, they generate nonlinear effects such as self-phase modulation (SPM), cross-phase modulation (XPM), and four-wave mixing (FWM). These nonlinear effects are dependent on optical power and fiber length and accumulate over transmission distance. For dense wavelength-division multiplexing (DWDM) transmission, when the optical power entering the transmission fiber is high and the transmission distance is long, the noise introduced by these nonlinear effects is nonnegligible. In long-haul optical transmission, due to nonlinear effects in the fiber, the optical power at the transmitting end cannot be increased indefinitely, thus limiting the transmission distance. Therefore, suppressing the nonlinearities generated in the fiber is key to increasing the power and, consequently, the transmission distance of optical systems. However, since nonlinear processes are dependent on signal power, which varies with transmission, and the diverse wavelength distribution and mutual influences of wavelengths in DWDM systems, it is difficult to simulate these nonlinear processes with simple models. Consequently, compensating for nonlinearities is often complex.

[0003] Existing nonlinearity compensation technologies are primarily implemented through digital signal processing (DSP), such as the Digital Back Propagation (DBP) algorithm. This algorithm uses parameters such as the actual link length, loss, dispersion, and nonlinearity to create a channel model. These parameters are then negated, and the received electrical signal is iteratively calculated to transmit a virtual link with the opposite sign of the actual link, thereby offsetting the nonlinearity accumulated during transmission. This method consumes a large amount of computing resources, results in high latency and energy consumption, and the resulting gains are limited, typically around 1dB. Summary of the Invention

[0004] The present application provides a nonlinear effect suppression link and a design method, device and computer-readable storage medium thereof, which can solve the technical problem of poor nonlinear compensation effect in the prior art.

[0005] In a first aspect, an embodiment of the present application provides a nonlinear effect suppression link, the nonlinear effect suppression link comprising a first wavelength converter and a second wavelength converter, wherein: One end of the first wavelength converter is connected to the signal transmitting end via a first optical fiber link, and the other end is connected to one end of the second wavelength converter via a second optical fiber link; the other end of the second wavelength converter is connected to the signal receiving end via a third optical fiber link; the first wavelength converter is used to convert the optical signal from the first wavelength band to the second wavelength band, and the second wavelength converter is used to convert the optical signal from the second wavelength band to the first wavelength band; The distance between the first wavelength converter and the signal transmitting end is , the distance between the first wavelength converter and the second wavelength converter is , the distance between the second wavelength converter and the signal receiving end is , and satisfy:

[0006]

[0007] in, is the link distance from the signal sending end to the signal receiving end, is the nonlinear coefficient of the first band, is the optical fiber loss in the first band, is the nonlinear coefficient of the second band, is the fiber loss in the second band, is a natural constant.

[0008] In conjunction with the first aspect, in one embodiment, .

[0009] In combination with the first aspect, in one embodiment, the first wavelength converter includes a first dispersion compensation device, and the second wavelength converter includes a second dispersion compensation device.

[0010] In combination with the first aspect, in one embodiment, the compensation value of the first dispersion compensation device is , the compensation value of the second dispersion compensation device is ,in:

[0011]

[0012]

[0013]

[0014] is the dispersion value at the phase matching wavelength, is the fiber chromatic dispersion in the first wavelength band, is the fiber chromatic dispersion in the second band.

[0015] In combination with the first aspect, in one embodiment, the first dispersion compensating component and the second dispersion compensating component are dispersion compensating optical fibers or chirped fiber gratings.

[0016] In a second aspect, an embodiment of the present application provides a method for designing a link with nonlinear effect suppression, the method comprising: Determine the distance between the first wavelength converter and the signal transmitting end through the position design formula , the distance between the first wavelength converter and the second wavelength converter And the distance between the second wavelength converter and the signal receiving end , where the position design formula includes:

[0017]

[0018] in, is the link distance from the signal sending end to the signal receiving end, is the nonlinear coefficient of the first band, is the optical fiber loss in the first band, is the nonlinear coefficient of the second band, is the fiber loss in the second band, is a natural constant.

[0019] In conjunction with the second aspect, in one embodiment, the position design formula further includes: .

[0020] In conjunction with the second aspect, in one embodiment, the nonlinear effect suppression link design method further includes: Determine the compensation value of the first dispersion compensation device in the first wavelength converter according to the compensation value design formula and the compensation value of the second dispersion compensation device in the second wavelength converter , where the compensation value design formula includes:

[0021]

[0022]

[0023]

[0024] is the dispersion value at the phase matching wavelength, is the fiber chromatic dispersion in the first wavelength band, is the fiber chromatic dispersion in the second band.

[0025] In a third aspect, an embodiment of the present application provides a nonlinear effect suppression link design device, which includes a processor, a memory, and a nonlinear effect suppression link design program stored in the memory and executable by the processor, wherein when the nonlinear effect suppression link design program is executed by the processor, the steps of the nonlinear effect suppression link design method described in the second aspect are implemented.

[0026] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, on which a nonlinear effect suppression link design program is stored, wherein when the nonlinear effect suppression link design program is executed by a processor, the steps of the nonlinear effect suppression link design method described in the second aspect are implemented.

[0027] The beneficial effects of the technical solutions provided in the embodiments of the present application include: In the embodiment of the present application, one end of the first wavelength converter is connected to the signal transmitting end through a first optical fiber link, and the other end is connected to one end of the second wavelength converter through a second optical fiber link; the other end of the second wavelength converter is connected to the signal receiving end through a third optical fiber link; the first wavelength converter is used to convert the optical signal from the first wavelength band to the second wavelength band, and the second wavelength converter is used to convert the optical signal from the second wavelength band to the first wavelength band; the distance between the first wavelength converter and the signal transmitting end is , the distance between the first wavelength converter and the second wavelength converter is , the distance between the second wavelength converter and the signal receiving end is , and satisfy:

[0028]

[0029] in, is the link distance from the signal sending end to the signal receiving end, is the nonlinear coefficient of the first band, is the optical fiber loss in the first band, is the nonlinear coefficient of the second band, is the fiber loss in the second band, The embodiments of the present application use two wavelength converters in an optical fiber link and determine the placement of the two wavelength converters according to a specific method, which can effectively compensate for the signal degradation caused by the accumulation of nonlinear effects during optical fiber transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of traditional C-band direct transmission and nonlinear accumulation at the end of the optical fiber; Figure 2 Schematic diagram of nonlinear compensation based on the solution of the present application (taking conversion to the S band as an example) and nonlinear accumulation at the end of the optical fiber; Figure 3 This is a structural diagram of an embodiment of a nonlinear effect suppression link of the present application; Figure 4 Schematic diagram comparing the transmission performance of the direct transmission solution and the solution of the present application when the input single-wavelength optical power is 0 dBm; Figure 5 Schematic diagram comparing the transmission performance of the direct transmission solution and the solution of the present application when the input single-wavelength optical power is 5dBm; Figure 6 Schematic diagram of SRS power transfer for wavelength conversion compensation; Figure 7 A schematic diagram comparing transmission results after correcting the nonlinear coefficient and loss coefficient considering band differences; Figure 8 Schematic diagram of the effect of the ratio of the transmission distances of the first and last optical fiber segments on the nonlinear suppression effect; Figure 9 Schematic diagram of wavelength conversion phase mismatch introduced for dispersion; Figure 10 Schematic diagram of dispersion compensation efficiency under different span lengths; Figure 11 Schematic diagram of the nonlinear compensation system for conversion between C-band and L-band; Figure 12 Schematic diagram of the compensation of SRS power transfer caused by conversion between C-band and L-band; Figure 13 Schematic diagram of the nonlinear compensation system for converting C-band to S-band and L-band to U-band; Figure 14 Schematic diagram of the nonlinear compensation system for mutual conversion between the S+Cb band and the Cr+L band; Figure 15 This is a schematic diagram of the hardware structure of the nonlinear effect suppression link design device involved in the embodiment of the present application. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0032] First, some technical terms in this application are explained to facilitate those skilled in the art to understand this application.

[0033] Based on the analysis of the nonlinear noise accumulation process of the kth wave of the wavelength-division multiplexing (WDM) signal during transmission along the optical fiber, it can be seen that nonlinear phase shifts such as SPM, XPM, and FWM are all accumulated in the imaginary part. Therefore, the nonlinear accumulation amount can be directly negative through phase conjugation; and in addition to generating noise in the channel, FWM will also generate new wavelength sidebands outside the original wavelength range. Phase conjugation can be achieved by using a wavelength converter, that is, the imaginary part of the complex amplitude of the above signal is negated. Based on the Kerr effect in customized optical devices, such as the third-order FWM effect, or the second-order SHG (Second Harmonic Generation) effect and the DFG (Difference Frequency Generation) effect, wide-spectrum wavelength conversion can be achieved, the original multi-wave signal is symmetrically flipped, and the converted signal is conjugated with the original signal. Taking the conversion from C-band to S-band as an example, if the converted conjugated signal is transmitted the same distance in the optical fiber, it can ideally compensate for the nonlinear noise generated. For example Figure 1 and Figure 2 As shown, Figure 1 Schematic diagram of traditional C-band direct transmission and nonlinear accumulation at the end of the optical fiber; Figure 2 Schematic diagram of nonlinear compensation (taking conversion to S band as an example) and nonlinear accumulation at the end of the optical fiber based on the solution of the present application.

[0034] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0035] In a first aspect, an embodiment of the present application provides a nonlinear effect suppression link.

[0036] In one embodiment, referring to Figure 3 , Figure 3 This is a structural diagram of an embodiment of the nonlinear effect suppression link of this application. Figure 3 As shown, the nonlinear effect suppression link includes a first wavelength converter WC1 and a second wavelength converter WC2, wherein: One end of the first wavelength converter WC1 is connected to the signal transmitting end Tx via a first optical fiber link, and the other end is connected to one end of the second wavelength converter WC2 via a second optical fiber link; the other end of the second wavelength converter WC2 is connected to the signal receiving end Rx via a third optical fiber link. The first wavelength converter WC1 is used to convert optical signals from the first wavelength band A to the second wavelength band B, and the second wavelength converter WC2 is used to convert optical signals from the second wavelength band B to the first wavelength band A. The distance between the first wavelength converter WC1 and the signal transmitting end Tx is , the distance between the first wavelength converter WC1 and the second wavelength converter WC2 is , the distance between the second wavelength converter WC2 and the signal receiving end Rx is , and satisfy:

[0037]

[0038] in, is the link distance from the signal transmitting end Tx to the signal receiving end Rx, is the nonlinear coefficient of the first band A, is the fiber loss in the first band A, is the nonlinear coefficient of the second band B, is the fiber loss in the second band B, is a natural constant.

[0039] In this embodiment, in the above formula, 、 、 is a known value.

[0040] On the basis of the above, we can judge Is it known? If yes, no additional processing is required. If not, the optical fiber loss value of the second band B needs to be measured. , or according to Perform fitting calculation. For the fitting calculation method, preferably, it can be based on the optical fiber standard or batch loss curve, according to the known Perform translation correction calculations.

[0041] Further, judging Is it known? If so, no additional processing is required. If not, the effective mode field area of band A must be calculated first. , then by the formula Get the effective mode field area of band B , and then according to get Alternatively, the effective mode field area of band B can be calculated by finite element modeling or other methods. , and then according to get .in, is the central wavelength of band A, is the central wavelength of band B, is the second-order nonlinear refractive index coefficient of the optical fiber.

[0042] Two wavelength converters, WC1 and WC2, are used in the optical fiber transmission link to convert A-band signals to B-band and back to A-band, respectively. Wavelength converters WC1 and WC2 are capable of converting the entire A-band signal or a portion of it to the B-band, and back to the A-band, respectively. Their frequency domain response exhibits symmetrical phase-spectral inversion, enabling phase conjugation of the entire A-band signal or a portion of it.

[0043] Furthermore, in one embodiment, .

[0044] In this embodiment, in order to further optimize the nonlinear effect suppression effect, the limit .

[0045] In the embodiment of the present application, one end of the first wavelength converter is connected to the signal transmitting end through a first optical fiber link, and the other end is connected to one end of the second wavelength converter through a second optical fiber link; the other end of the second wavelength converter is connected to the signal receiving end through a third optical fiber link; the first wavelength converter is used to convert the optical signal from the first wavelength band to the second wavelength band, and the second wavelength converter is used to convert the optical signal from the second wavelength band to the first wavelength band; the distance between the first wavelength converter and the signal transmitting end is , the distance between the first wavelength converter and the second wavelength converter is , the distance between the second wavelength converter and the signal receiving end is , and satisfy:

[0046]

[0047] in, is the link distance from the signal sending end to the signal receiving end, is the nonlinear coefficient of the first band, is the optical fiber loss in the first band, is the nonlinear coefficient of the second band, is the fiber loss in the second band, The embodiments of the present application use two wavelength converters in an optical fiber link and determine the placement of the two wavelength converters according to a specific method, which can effectively compensate for the signal degradation caused by the accumulation of nonlinear effects during optical fiber transmission.

[0048] Furthermore, in one embodiment, the first wavelength converter includes a first dispersion compensation device, and the second wavelength converter includes a second dispersion compensation device.

[0049] Furthermore, in one embodiment, the compensation value of the first dispersion compensation device is , the compensation value of the second dispersion compensation device is ,in:

[0050]

[0051]

[0052]

[0053] is the dispersion value at the phase matching wavelength, is the fiber chromatic dispersion in the first wavelength band, is the fiber chromatic dispersion in the second band.

[0054] Furthermore, in one embodiment, the first dispersion compensating device and the second dispersion compensating device are dispersion compensating optical fibers or chirped fiber gratings.

[0055] In this embodiment, is a known value.

[0056] On the basis of the above, we can judge Is it known? If so, no additional processing is required. If not, the fiber dispersion slope ,pass Calculated .

[0057] Based on the placement of two wavelength converters at specific positions of the optical fiber link, the first dispersion compensation device and the second dispersion compensation device compensate the optical signal according to specific compensation values respectively, further optimizing the nonlinear effect suppression effect.

[0058] The nonlinear Schrödinger equation model is used to simulate the signal degradation compensation effect during the transmission process. The simulation conditions are as follows: the first band A is the C band, 40 wavelengths are used within the C120 range, and the wavelength interval is 150GHz. The second band B is the S band, the conversion efficiency is 0dB, and the single-wavelength optical power into the fiber is 0dBm. The simulation results are as follows: Figure 4 As shown, Figure 4The figure shows a comparison of the transmission performance of a direct transmission solution and the solution of this application when the input single-wavelength optical power is 0dBm. The direct transmission solution directly transmits C-band optical signals between the signal transmitter and the signal receiver. As can be seen, the noise sidebands generated by FWM are significantly suppressed by adopting the solution of this application, achieving an approximately 2dB improvement in the SNR at the end.

[0059] Furthermore, the input single-wavelength optical power is increased to 5dBm. Since the nonlinear effect is enhanced with the increase of power, the nonlinear degradation is more significant at this time. The simulation results are as follows: Figure 5 As shown, Figure 5 Schematic diagram showing the comparison of transmission performance between the direct transmission solution and the solution of this application when the optical power of the single-wavelength optical input fiber is 5dBm. Figure 5 As shown, even with a larger effective mode area fiber, nonlinear impairments still increase, the noise sideband power generated by FWM increases significantly, and the SNR of direct transmission degrades by 3.5dB compared to the case of 0dBm fiber input power. By adopting the solution of this application, the noise sideband generated by FWM is significantly suppressed, and the SNR at the end is improved by approximately 5dB. Therefore, in scenarios with high fiber input power and strong nonlinearity, the benefits of this invention in nonlinear suppression are even more significant.

[0060] In summary, the present application can compensate for signal degradation caused by nonlinear effects, allowing for increased transmitting power and longer transmission distance.

[0061] In addition, the principle on which this application is based is all-optical conversion, which is transparent to the modulation format and modulation rate and is compatible with any optical module. While compensating for nonlinearity, it also has a compensating effect on dispersion, reducing the dispersion accumulated at the receiving end. If a wavelength conversion device with gain (such as an optical parametric amplifier) is used, amplification can be achieved while converting the wavelength band, thereby replacing the original optical amplifier in the corresponding position, while compensating for nonlinearity without increasing the number of single disks in the system and the complexity of the system. In addition, the present invention can also compensate for the power transfer caused by the SRS effect during the transmission of WDM signals, such as Figure 6 As shown, Figure 6 This is a schematic diagram of wavelength conversion compensating SRS power transfer. In particular, in extended-band systems, the present invention can compensate for inter-band power transfer, facilitating wavelength balancing in extended-band systems and reducing the difficulty of OSNR leveling at the receiving end.

[0062] The technical solution of this application is further described below through four embodiments: Example 1: A multi-span C-band EDFA amplification system using the S-band for wavelength conversion.

[0063] The wavelength converter positions are spaced apart based on the nonlinear induced phase shift Ø NL ≈γP in Leff , where P in is the single wave input fiber power, L eff is the effective length of the optical fiber. Considering the commutativity of nonlinear accumulation and elimination, it is obvious that : : =1:2:1. A 1000km transmission (single span 100km) simulation was conducted using a 25Gbd PM-QPSK signal using G.652.D fiber and an amplifier noise figure of 6dB. In this configuration, the effects of fiber nonlinearity, dispersion, and loss were not considered. The simulated Q2VS single-wavelength fiber power results are shown below. Figure 7 shown. Figure 7 This is a comparison diagram of the transmission results after correcting the nonlinear coefficient and loss coefficient considering the band difference. Considering the difference in the nonlinear coefficient γ of the band before and after conversion, More preferably, ,Right now .in, If the fiber manufacturer does not provide Parameters can be based on existing Parameters, reverse calculation of the effective mode field area of the optical fiber , calculated by finite element modeling and other methods , thus calculating . The value is usually 1.2~2 times of this simulation case. Therefore, the fiber length calculated by correcting this parameter is 、 and Will improve the system transmission performance. Figure 7 shown.

[0064] In addition, considering the difference in optical fiber loss coefficients between the C-band and S-band where the signal is located before and after wavelength conversion, according to the definition of the effective length of the optical fiber, it is required , better, , the specific value is solved by numerical value. Parameters, you can refer to the optical fiber loss curve, and the actual Perform fitting calculations. The transmission performance will continue to improve. Figure 7 shown.

[0065] In addition to determining the S-band transmission With C-band transmission 、 In addition to the relationship between 、 The ratio of also needs to be optimized (i.e. the above-mentioned "better value"), that is, changing occupy The ratio of is used to calculate the maximum allowable increase in single-wavelength fiber power. Figure 8 visible, Figure 8 The figure is a schematic diagram showing the effect of the ratio of the transmission distances of the first and last optical fibers on the nonlinear suppression effect. and When they are equal, the nonlinear suppression effect is optimal.

[0066] Consider the influence of optical fiber chromatic dispersion in different wavelength bands: Since the transmission signal is a wide-spectrum WDM signal, the phase matching between each wavelength and the pump varies with wavelength due to the dispersion, which leads to phase matching failure, reduced wavelength conversion efficiency, and decreased nonlinear suppression effect. Figure 9 As shown, Figure 9 Schematic diagram of wavelength conversion phase mismatch introduced by dispersion. Dispersion adjustment can be achieved by adding a dispersion compensation unit to the wavelength converter. The dispersion compensation device and compensation value have been described above. Taking dispersion compensating fiber (DCF) as an example, its required length can be determined by the compensation value it needs to provide. However, since dispersion compensation can only achieve relatively complete compensation for a certain wavelength (usually the center wavelength), and since the dispersion slope of the transmission fiber is not constant, the compensation efficiency will still decrease for edge wavelengths, such as Figure 10 As shown, Figure 10 Schematic diagram of dispersion compensation efficiency under different span lengths.

[0067] Example 2: C+L band transmission system, C and L bands are converted to each other.

[0068] For C+L systems, the present invention can also be applied to realize simultaneous compensation of nonlinearity of C-band and L-band by utilizing the interchange of C-band and L-band. Figure 11 As shown, Figure 11Schematic diagram of a nonlinear compensation system for conversion between the C-band and L-band. After transmission through L1, the C+L signal is split into two paths, the C-band and L-band, using components such as band couplers and wavelength selective switches. The original C-band signal light carrying the service is then converted to the L-band through a wavelength converter, simultaneously achieving phase conjugation. Simultaneously, the original L-band signal light carrying the service is converted to the C-band through a wavelength converter, simultaneously achieving phase conjugation. After conversion, the signals are combined using components such as band couplers and wavelength selective switches for continued transmission along the optical fiber link. After transmission through L2, the conjugated signals of the L-band and C-band are similarly converted back to the C-band and L-band, respectively, combined, and then transmitted through L3. At the end of the link, nonlinear suppression is achieved in both the C-band and L-band. If a reciprocal conversion scheme is employed, since theoretically the optimal L1, L2, and L3 values for the C-band and L-band are not completely identical, staggering the locations of the C-band and L-band converters will result in spectral overlap between the C-band signal and the signal conjugated from the L-band on the transmission link. Therefore, wavelength conversion for both bands must be performed at the same location. In summary, adopting a L1:L2:L3 ratio of 1:2:1 in this system will achieve a more balanced compensation effect. However, the accumulated dispersion caused by phase mismatch at each wavelength converter can be compensated using the calculation method described in Example 1, achieving better conversion efficiency and nonlinear suppression.

[0069] This solution can fully utilize various single disks in the existing C+L system. Based on the existing C+L system, it only needs to connect wavelength converters at the site location and replace the fiber connecting the band coupler of the C+L multiplexing after conversion (or replace the wavelength assignment port of the wavelength conversion switch).

[0070] The present invention can also compensate for the power transfer caused by the SRS effect during the transmission of the C+L signal, such as Figure 12 As shown, Figure 12 This diagram illustrates compensation for SRS power transfer during C-band to L-band conversion. In addition to compensating for inter-channel power transfer, this invention also compensates for power transfer from the C-band to the L-band, reducing the slope at the receiving end to zero. This SRS compensation facilitates C+L wavelength balancing and reduces the difficulty of OSNR leveling at the receiving end.

[0071] Example 3: C+L band transmission system, using S and U bands for wavelength conversion.

[0072] The nonlinear suppression of the C+L system can also be achieved by converting the C-band signal to the S-band with a shorter wavelength and converting the L-band signal to the U-band with a longer wavelength, such as Figure 13 As shown, Figure 13Schematic diagram of the nonlinear compensation system for converting C-band to S-band and L-band to U-band. This conversion method avoids the problem of spectrum overlap (wavelength conflict) in C-band to L-band conversion schemes, which prevents the optimal wavelength converter positions for the C and L bands from being set separately. Figure 13 In the CS wavelength conversion and LU wavelength conversion occur at different spatial distances. For the C band, the fiber link distances L1, L2, and L3 corresponding to the positions of WC1 and WC2 are L I , L II +2ΔL、L III For L band, the fiber link distances L1, L2, and L3 corresponding to the positions of WC1 and WC2 are L I +ΔL, L II , L III +ΔL. According to the above content, calculate the L1, L2, and L3 values corresponding to the C band and L band respectively, and then you can get L according to the above relationship. I , L II , L III , ΔL, and thus determine the optimal deployment position of each wavelength converter.

[0073] Example 4: S+C+L band system, S+C and C+L bands are converted to each other.

[0074] For systems with more bands, such as the S+C+L system, a wavelength converter with a wider conversion bandwidth can also be used. The C band is divided into a short-wave band (Cb) and a long-wave band (Cr), so that the total spectrum of the S+C+L band can be symmetrically divided into two parts, namely S+Cb and Cr+L. Similar to the steps of Example 2, the signals in the S+Cb band and the signals in the Cr+L band are converted to the Cr+L and S+Cb bands respectively using a wide-spectrum band converter to achieve phase conjugation, and then converted back to the S+Cb and Cr+L bands respectively after transmission, as shown in FIG. Figure 14 As shown, Figure 14 This diagram shows a nonlinear compensation system for converting between the S+Cb band and the Cr+L band. Although the spectral division method for band conversion (S+Cb and Cr+L) differs from the spectral division method used by the amplifier station in the link (S, C, and L), the complete S+C+L band signal is present before and after the conversion. Therefore, the wavelength conversion process has no impact on the optical amplification in the link. This solution also allows for simultaneous compensation of nonlinear noise and SRS power transfer in the S+C+L band.

[0075] In a second aspect, an embodiment of the present application also provides a method for designing a link that suppresses nonlinear effects.

[0076] In one embodiment, a nonlinear effect suppression link design method includes: Determine the distance between the first wavelength converter and the signal transmitting end through the position design formula , the distance between the first wavelength converter and the second wavelength converter And the distance between the second wavelength converter and the signal receiving end , where the position design formula includes:

[0077]

[0078] in, is the link distance from the signal sending end to the signal receiving end, is the nonlinear coefficient of the first band, is the optical fiber loss in the first band, is the nonlinear coefficient of the second band, is the fiber loss in the second band, is a natural constant.

[0079] Furthermore, in one embodiment, the position design formula also includes: .

[0080] Furthermore, in one embodiment, the nonlinear effect suppression link design method further includes: Determine the compensation value of the first dispersion compensation device in the first wavelength converter according to the compensation value design formula and the compensation value of the second dispersion compensation device in the second wavelength converter , where the compensation value design formula includes:

[0081]

[0082]

[0083]

[0084] is the dispersion value at the phase matching wavelength, is the fiber chromatic dispersion in the first wavelength band, is the fiber chromatic dispersion in the second band.

[0085] Furthermore, in one embodiment, the first dispersion compensating device and the second dispersion compensating device are dispersion compensating optical fibers or chirped fiber gratings.

[0086] The specific embodiments of the nonlinear effect suppression link design method can refer to the various embodiments of the nonlinear effect suppression link described above, and will not be described in detail here.

[0087] In a third aspect, an embodiment of the present application provides a nonlinear effect suppression link design device, which may be a personal computer (PC), a laptop computer, a server, or other device with data processing capabilities.

[0088] Reference Figure 15 , Figure 15 Schematic diagram of the hardware structure of the nonlinear effect suppression link design device involved in the embodiment of the present application. In the embodiment of the present application, the nonlinear effect suppression link design device may include a processor, a memory, a communication interface, and a communication bus.

[0089] The communication bus may be of any type and is used to interconnect the processor, memory, and communication interface.

[0090] Communication interfaces include input / output (I / O), physical, and logical interfaces, which interconnect components within the nonlinear effect suppression link design device and other devices (such as other computing devices or user equipment). Physical interfaces can be Ethernet, fiber, or ATM interfaces; user equipment can include displays and keyboards.

[0091] The memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.

[0092] The processor may be a general-purpose processor that can invoke a nonlinear effect suppression link design program stored in a memory and execute the nonlinear effect suppression link design method provided in the embodiments of the present application. For example, the general-purpose processor may be a central processing unit (CPU). The method executed when the nonlinear effect suppression link design program is invoked can be referenced from the various embodiments of the nonlinear effect suppression link design method of the present application and will not be further described here.

[0093] Those skilled in the art will understand that Figure 15The hardware structure shown in the figure does not constitute a limitation to the present application and may include more or fewer components than shown in the figure, or a combination of certain components, or a different arrangement of components.

[0094] In a fourth aspect, an embodiment of the present application also provides a computer-readable storage medium.

[0095] The computer-readable storage medium of the present application stores a nonlinear effect suppression link design program, wherein when the nonlinear effect suppression link design program is executed by a processor, the steps of the nonlinear effect suppression link design method as described above are implemented.

[0096] Among them, the method implemented when the nonlinear effect suppression link design program is executed can refer to the various embodiments of the nonlinear effect suppression link design method of the present application, and will not be repeated here.

[0097] It should be noted that the serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0098] The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. The terms "first", "second" and "third" are used to distinguish different objects, etc., and do not represent a sequence, nor do they limit the "first", "second" and "third" to different types.

[0099] In the description of the embodiments of this application, the words "exemplary," "for example," or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary," "for example," or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary," "for example," or "for example" is intended to present the relevant concepts in a concrete manner.

[0100] In the description of the embodiments of the present application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, “multiple” refers to two or more than two.

[0101] In some processes described in the embodiments of the present application, multiple operations or steps are included that appear in a specific order. However, it should be understood that these operations or steps may not be performed in the order in which they appear in the embodiments of the present application or may be performed in parallel. The sequence numbers of the operations are only used to distinguish between different operations, and the sequence numbers themselves do not represent any order of execution. In addition, these processes may include more or fewer operations, and these operations or steps may be performed in sequence or in parallel, and these operations or steps may be combined.

[0102] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, or the part that contributes to the existing technology, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above and includes a number of instructions for enabling a terminal device to execute the methods described in each embodiment of this application.

[0103] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A nonlinear effect suppression link, characterized in that: The nonlinear effect suppression link includes a first wavelength converter and a second wavelength converter, wherein: One end of the first wavelength converter is connected to the signal transmitting end via a first optical fiber link, and the other end is connected to one end of the second wavelength converter via a second optical fiber link; the other end of the second wavelength converter is connected to the signal receiving end via a third optical fiber link; the first wavelength converter is used to convert the optical signal from the first wavelength band to the second wavelength band, and the second wavelength converter is used to convert the optical signal from the second wavelength band to the first wavelength band; The distance between the first wavelength converter and the signal transmitting end is , the distance between the first wavelength converter and the second wavelength converter is , the distance between the second wavelength converter and the signal receiving end is , and satisfy: in, is the link distance from the signal sending end to the signal receiving end, is the nonlinear coefficient of the first band, is the optical fiber loss in the first band, is the nonlinear coefficient of the second band, is the fiber loss in the second band, is a natural constant.

2. The nonlinear effect suppression link according to claim 1, wherein: 。 3. The nonlinear effect suppression link according to claim 1, wherein: The first wavelength converter includes a first dispersion compensation device, and the second wavelength converter includes a second dispersion compensation device.

4. The nonlinear effect suppression link according to claim 3, wherein: The compensation value of the first dispersion compensation device is , the compensation value of the second dispersion compensation device is ,in: is the dispersion value at the phase matching wavelength, is the fiber chromatic dispersion in the first wavelength band, is the fiber chromatic dispersion in the second band.

5. The nonlinear effect suppression link according to claim 4, wherein: The first dispersion compensating device and the second dispersion compensating device are dispersion compensating optical fibers or chirped fiber gratings.

6. A nonlinear effect suppression link design method, characterized in that: The nonlinear effect suppression link design method comprises: Determine the distance between the first wavelength converter and the signal transmitting end through the position design formula , the distance between the first wavelength converter and the second wavelength converter And the distance between the second wavelength converter and the signal receiving end , where the position design formula includes: in, is the link distance from the signal sending end to the signal receiving end, is the nonlinear coefficient of the first band, is the optical fiber loss in the first band, is the nonlinear coefficient of the second band, is the fiber loss in the second band, is a natural constant.

7. The nonlinear effect suppression link design method according to claim 6, wherein: The location design formula also includes: 。 8. The nonlinear effect suppression link design method according to claim 6, wherein: The nonlinear effect suppression link design method further includes: Determine the compensation value of the first dispersion compensation device in the first wavelength converter according to the compensation value design formula and the compensation value of the second dispersion compensation device in the second wavelength converter , where the compensation value design formula includes: is the dispersion value at the phase matching wavelength, is the fiber chromatic dispersion in the first wavelength band, is the fiber chromatic dispersion in the second band.

9. A nonlinear effect suppression link design device, characterized in that: The nonlinear effect suppression link design device includes a processor, a memory, and a nonlinear effect suppression link design program stored in the memory and executable by the processor, wherein when the nonlinear effect suppression link design program is executed by the processor, the steps of the nonlinear effect suppression link design method as described in any one of claims 6 to 8 are implemented.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a nonlinear effect suppression link design program, wherein when the nonlinear effect suppression link design program is executed by a processor, the steps of the nonlinear effect suppression link design method according to any one of claims 6 to 8 are implemented.

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