WO2011079610A1

WO2011079610A1 - Method and apparatus for adaptive dispersion compensation

Info

Publication number: WO2011079610A1
Application number: PCT/CN2010/074764
Authority: WO
Inventors: 田野; 李新兵; 蔡鸿鹏; 赵祖慧
Original assignee: 中兴通讯股份有限公司
Priority date: 2009-12-29
Filing date: 2010-06-30
Publication date: 2011-07-07
Also published as: CN101753218B; CN101753218A

Abstract

A method and an apparatus for adaptive dispersion compensation is provided by the present invention, and the method comprises: a main control module controls a dispersion adjustment module to perform dispersion coarse adjusting and detects the bit error before correction, if the bit error before correction counting is valid, then sets the current dispersion value as the initial dispersion value and controls the dispersion adjustment module to perform the dispersion fine adjustment; when the main control module controls the dispersion adjustment module to perform dispersion fine adjustment, it takes initial dispersion value as the center, searches the scope of the bit error before correction counting being valid, sets the dispersion value corresponding to the minimum bit error rate before correction as a better dispersion value, then controls the dispersion adjustment module to perform dispersion optimization; and when the main control module controls the dispersion adjustment module to perform the dispersion optimization, it takes the better dispersion value as the center, obtains one or more dispersion values from both sides respectively, detects the corresponding bit error rate before correction, sets the detected dispersion value corresponding to the minimum bit error rate before correction as a new better dispersion value, and further performs dispersion optimization until reaches the predetermined condition of the termination of the optimization, sets the current better dispersion value as the optimum dispersion value, and controls the dispersion adjustment module to keep the dispersion. The present invention can tracks the change of the system dispersion and makes adjustment automatically, which improves the performance of optical channel access equipments and the anti-interference ability of wavelength-division systems.

Description

Method and device for adaptive dispersion compensation

Technical field

The present invention relates to the field of wavelength division communication, and in particular, to a method and apparatus for adaptive dispersion compensation.

Background technique

During the long-distance transmission of wavelength division, due to various factors such as environment, fiber optics, equipment, etc., the system has a dispersion effect. Although each transmission station uses partial dispersion compensation technology to improve, the overall compensation is not accurate, and the light is transmitted at a high rate. Channel devices, such as single-wave 40G or 100G devices, do not work without a dedicated dispersion compensation device, so dispersion compensation devices are essential.

Although the traditional dispersion compensation equipment can compensate the access residual dispersion of the system transmission, the applicable method does not adapt to the complex changes of the system. For example, some dispersion compensation units only support manual setting, and the dispersion range of the station needs to be manually calculated. Then manually try to set in this range; some dispersion compensation units support automatic dispersion search compensation, but because you do not know the specific characteristics of the system can only set a fixed search step, the speed is very slow, and can not judge the removal of the local best.

Summary of the invention

The technical problem to be solved by the present invention is to provide a method and apparatus for adaptive dispersion compensation, which improves the adaptability and stability of the dispersion compensation device to the system.

In order to solve the above technical problem, the present invention provides a method for adaptive dispersion compensation, comprising: the main control module controls the dispersion adjustment module to perform coarse dispersion adjustment, and detects error before error correction, and if the error count is valid before error correction, Then using the current dispersion value as the starting dispersion value, and controlling the dispersion adjustment module to perform dispersion adjustment;

When the main control module controls the dispersion adjustment module to perform dispersion fine adjustment, the search is performed within the range where the error count is valid before the error correction, and the dispersion value corresponding to the error rate before the minimum error correction is used as the better dispersion value. And then controlling the dispersion adjustment module to perform dispersion optimization;

When the main control module controls the dispersion adjustment module to perform dispersion optimization, one or more dispersion values are taken from each side with the better dispersion value as the center, and the corresponding error rate before error correction is detected, and the detected minimum correction is performed. The dispersion value corresponding to the error rate before error is used as the new better dispersion value, and the dispersion optimization is further performed until the preset termination optimization condition is reached, and the current better dispersion value is taken as the optimal dispersion value, and the dispersion adjustment module is controlled to execute. Dispersion retention.

Preferably, the above method may further include:

The main control module 釆 collects the optical power of the optical amplifying module. If the incoming optical power collected by the 釆 is lower than the unlighted threshold, the input control is no light, and the main control module controls the optical amplifying module to turn off the light, and controls the dispersion adjustment module. Perform dispersion retention.

Preferably, the above method may also have the following features:

The step of the main control module controlling the dispersion adjustment module to perform coarse dispersion adjustment comprises: controlling, by the main control module, the dispersion adjustment module to search in a large step, until the error count is valid before detecting the error correction; the step size of the large step 50 ps/nm ~ 150ps/nm „

Preferably, the above method may also have the following features:

The step of the main control module controlling the dispersion adjustment module to perform dispersion fine adjustment comprises: controlling, by the main control module, the dispersion adjustment module to start the dispersion value as the center, and searching in the middle step to increase and decrease the dispersion value, until the detection The error count is invalid until the error correction; the step size of the medium step is 10 ps/nm ~ 30 ps/nm.

Preferably, the above method may also have the following features:

The step of the main control module controlling the dispersion adjustment module to perform dispersion optimization comprises: controlling, by the main control module, the dispersion adjustment module to take one or more dispersion values in the two directions of increasing and decreasing the dispersion value with the preferred dispersion value as a center, The interval between the dispersion values is less than 10 ps/nm;

The preset termination optimization condition is that the same dispersion value is continuously a better dispersion value, or the adjustment direction of the dispersion value is repeatedly changed.

Preferably, the above method may further include:

When the main control module controls the dispersion adjustment module to perform dispersion retention, if the error count before the error correction is detected but the error deterioration exceeds the limit, and the error is determined to be a non-burst error, the dispersion adjustment module is controlled to perform dispersion. optimization.

Preferably, the above method may further include: When the main control module controls the dispersion adjustment module to perform dispersion optimization or dispersion retention, if the error count before the error correction is detected to be invalid and continues for a specified time, the main control module controls the dispersion adjustment module to perform coarse dispersion adjustment;

When the main control module controls the dispersion adjustment module to perform dispersion fine adjustment, if the error count before the error correction is detected to be invalid and continues for a specified time, the error value before the error correction corresponding to the initial dispersion value or the current better dispersion value is detected. If it is invalid, the control dispersion adjustment module performs coarse dispersion adjustment. Otherwise, it continues to control the dispersion adjustment module to perform dispersion fine adjustment.

Preferably, the above method may further include:

When the main control module controls the dispersion adjustment module to perform dispersion optimization or dispersion retention or dispersion fine adjustment, since the error correction count before the error correction is invalid and continues for a specified time, the main control module controls the dispersion adjustment module to perform the coarse dispersion adjustment, if it detects Before the error correction is valid before the error correction and the error rate is less than the optimization threshold, the dispersion adjustment module is directly controlled to perform dispersion optimization.

In order to solve the above technical problem, the present invention further provides an apparatus for adaptive dispersion compensation, including an optical amplification module, a circulator, an error detection module, a dispersion adjustment module, and a main control module, wherein the optical amplification module is configured to Outputting the input light to the dispersion adjustment module through the circulator at a constant optical power;

The circulator is configured to transmit the output light of the optical amplifying module to the dispersion adjusting module, and superimpose and output the output light of the dispersion adjusting module and the output light of the optical amplifying module;

The error detection module is configured to detect error correction error of the output light of the circulator in real time; the dispersion adjustment module is configured to perform dispersion coarse adjustment, dispersion fine adjustment, dispersion optimization, and dispersion retention according to the dispersion value set by the main control module. ;

The main control module is configured to control the dispersion adjustment module to perform coarse dispersion adjustment, and determine whether the error count before the error correction is valid according to the error correction error detected by the error detection module, and if valid, the current dispersion value As the initial dispersion value, the control dispersion adjustment module performs dispersion fine adjustment; the main control module is further configured to detect the error correction detected by the error detection module when the dispersion adjustment module performs the dispersion fine adjustment, with the initial dispersion value as the center. The front error code counts the effective range search, and the dispersion value corresponding to the minimum error correction error rate is used as the better dispersion value, and then the dispersion adjustment module is controlled to perform dispersion optimization; the main control module is further configured to perform dispersion at the control dispersion adjustment module. Optimized dispersion value For the center, one or more dispersion values are taken from each side, and the bit error rate before the error correction detection module is detected by the error detection module, and the detected dispersion value corresponding to the minimum error correction error rate is used as the new preferred dispersion. The value further performs dispersion optimization until the preset termination optimization condition is reached, the current preferred dispersion value is taken as the optimal dispersion value, and the dispersion adjustment module is controlled to perform dispersion retention.

Preferably, the above device may also have the following features:

The main control module is further configured to set the optical power of the optical amplifying module. If the incoming optical power is lower than the unlighting threshold, the input optical is judged to be no light, the optical amplifying module is controlled to turn off the light, and the dispersion adjusting module is controlled to perform dispersion. maintain.

Compared with the traditional dispersion compensation device, the invention has obvious adaptive advantages, can search according to system dispersion variation without human intervention, and provides optimal signal quality for the optical channel access device. The invention improves the speed and accuracy of the dispersion search, can eliminate the local best advantage, the sudden disturbance of the filtering system, and improve the performance of the optical channel access device and the whole system, and has good application prospect and use value. BRIEF abstract

Figure la and Figure lb are measured curves of bit error rate/dispersion of 40G DPSK (Differential Phase Shift Keying);

2 is a schematic diagram of an apparatus for adaptive dispersion compensation according to an embodiment of the present invention;

3 is a schematic structural diagram of a dispersion adjustment module according to an embodiment of the present invention;

4 is a global diagram of dispersion adjustment and state change of an application example of the present invention. Preferred embodiment of the invention

The dispersion compensation of the actual system has a certain tolerance. The compensation value in this range can make the receiving device recognize the transmission signal, but the signal quality difference in this range is very large, except that the area where the identification signal needs to be found is needed. In addition, it is necessary to find the dispersion compensation value that makes the system transmission performance the best in this area, and when the system changes, the range and the optimal value also change, and it is necessary to keep track of the optimal dispersion compensation value. These are the systems. The best demand for dispersion compensation. The dispersion compensation tolerance is searched based on the absence of error correction before error correction. OTU (Optical transmit unit), frame loss, uncorrectable frame, etc., and the optimal dispersion value is judged by which dispersion value corresponds to the lowest error rate before error correction in the system.

Taking single-wave 40G transmission as an example, the system is analyzed. As shown in Figure la and Figure lb, the corresponding error rate and dispersion curve of the line-side optical module in DPSK coding mode are tested at the receiving end (other coding modes of light) The module has a similar curve). In Figure la, the bandwidth of the DPSK coded delay interferometer is Light (weak), that is, the selected bandwidth is 50 GHz; in Figure lb, the bandwidth of the DPSK coded delay interferometer is selected as Strong. That is, the selected bandwidth is 66.7 GHz. It can be seen from Fig. la and Fig. 1b that under different noise conditions, the dispersion tolerance of the system is generally greater than lOOps/nm, the shape of the dispersion and bit error rate curves are changed, and there are local optimum points.

In view of the deficiencies of the existing dispersion compensation system, in order to improve the adaptability and stability of the dispersion compensation device to the system, the present invention provides a method and apparatus for adaptive dispersion compensation, which may be an optical channel transmission access device. Part of it can also be made into a separate functional device. Through the effective dispersion adjustment control algorithm proposed by the present invention, the present invention can solve the drawbacks of the conventional dispersion compensation device, and automatically and accurately adjust to adapt to the system dispersion variation.

As shown in FIG. 2, the apparatus for adaptive dispersion compensation according to the embodiment of the present invention includes an optical amplifying module 201, a circulator 202, an error detecting module 203, a dispersion adjusting module 204, and a main control module 205, wherein the optical amplifying module 201 is generally An adjustable micro-optical amplifier component is arranged to output the input light to the dispersion adjustment module 204 via the circulator 202 at a constant optical power; that is, the module isolates optical power variations from the system input to the dispersion adjustment module 204 such that The device can be adapted to a wide range of light entering, and the optical amplifying module 201 selects a constant power output. Under the control of the main control module 205, different incoming lights pass through the optical amplifying module 201 and enter the subsequent modules with the same light output;

The circulator 202 is configured to transmit the output light of the optical amplifying module 201 to the dispersion adjusting module 204, and superimpose and output the output light of the dispersion adjusting module 204 and the output light of the optical amplifying module 201, thereby generating a dispersion compensation effect;

The error detection module 203 is usually a service signal framing chip, and is configured to detect the error pre-error error of the output light of the circulator 202 in real time (including the error error rate and the error count before the error correction), as the main control module. The control of 205 provides a basis; wherein, since the error detection module 203 usually uses telecommunications The detection is performed, so that the output light of the circulator 202 can be photoelectrically converted into an electrical signal through the receiving side of the optical module, and then input to the error detecting module 203 to detect the error;

The dispersion adjustment module 204 is configured to perform dispersion coarse adjustment, dispersion fine adjustment, dispersion optimization, and dispersion retention according to the dispersion value set by the main control module 205;

The main control module 205 is configured to send the dispersion value to be set to the dispersion adjustment module 204 according to the error correction error detected by the error detection module 203, and then control the dispersion adjustment module 204 to perform dispersion according to the dispersion adjustment control algorithm. Adjusting, and, according to the input optical power of the optical amplifying module 201, controlling the adjustable micro-optical amplification output, etc., so that the devices work together to complete the dispersion adaptive adjustment.

As shown in FIG. 3, the dispersion adjustment module 204 of the embodiment of the present invention includes a controller 2041, a comparator 2042, and a dispersion adjustment actuator 2043;

The controller 2041 (usually a logic control device, such as a CPLD (Complex Programmable Logic Device) or an FPGA (Field Programmable Gate Array)) is configured to receive the main control module 205. The dispersion value is converted into a control signal, and the control dispersion adjustment actuator 2043 performs dispersion adjustment, and transmits the dispersion value set by the main control module 205 (ie, the desired dispersion value) to the comparator 2042; and, the feedback of the receiving comparator 2042 The dispersion value has locked the signal and is fed back to the main control module 205, and the main control module 205 can continue to make a decision according to the locked state of the dispersion value;

The dispersion adjustment actuator 2043 is configured to perform dispersion adjustment according to the control of the controller 2041, and send the dispersion adjustment result to the comparator 2042;

The comparator 2042 is configured to compare the dispersion value sent by the controller 2041 with the dispersion adjustment result of the dispersion adjustment actuator 2043, if it is consistent, it is in a dispersion value locked state, and the feedback dispersion value has a lock signal to the control. 2041.

Based on the structure of the device for adaptive dispersion compensation described above, the device has the functions of adaptive dispersion compensation by the following methods in addition to the functions of conventionally formulating the dispersion value and issuing, and the conventional control algorithm improves the traditional dispersion compensation device. Insufficient.

The search of the optimal dispersion value has different granularity under different system conditions, and at the same time, the search speed and search accuracy are taken into consideration, and the local optimum is eliminated. The dispersion value mentioned in this process is the expected dispersion value. The expected dispersion value is inferred from the current system state of the master control module. The expected dispersion value is adjusted by the main control module to deliver the desired dispersion value to the dispersion adjustment module. After the controller controls the dispersion adjustment actuator, the master The control module periodically polls whether the comparator is locked to determine whether the desired dispersion value is set successfully. After the dispersion value is set successfully, the main control module collects the error status of the error detection module as the basis for the next decision.

The method for adaptive dispersion compensation in the embodiment of the present invention includes:

(1) Coarse adjustment stage:

The adaptive dispersion adjustment starts from this, the main control module controls the dispersion adjustment module to perform coarse dispersion adjustment, and detects the error before the error correction. If the error count before the error correction is valid, the current dispersion value is used as the initial dispersion value, and the dispersion is controlled. The adjustment module performs dispersion fine adjustment;

In this stage, in the case that the received service signal collected by the error detection module finds that the error count is invalid before the error correction, the main control module controls the dispersion adjustment module to search in a large step until the error correction is detected. The error count is valid (usually the frame loss alarm disappears), and the current dispersion value is recorded;

The step size of the large step can be set to 50 ps/nm ~ 150ps/nm, and the recommended step size is lOOps/ coarse search step can save search time.

(2) Fine tuning stage:

Specifically, the main control module controls the dispersion adjustment module to perform the search in the middle step to increase and decrease the dispersion value in the middle step, until the error count is invalid before detecting the error correction; The dispersion search does not fall into the local optimum, and the medium step size is used, because the medium step search searches for the exhaustive dispersion tolerance and does not fall into the local optimum. After the search is completed, the optimal dispersion value recorded in the search process is directly entered into the optimization phase;

Among them, the step size of the medium step is 10 ps/nm ~ 30ps/nm, and the recommended step value is 20ps/nm.

(3) Optimization stage:

When the main control module controls the dispersion adjustment module to perform dispersion optimization, the center of the better dispersion value is One or more dispersion values are taken on each side, and the corresponding error rate before error correction is detected, and the detected dispersion value corresponding to the minimum error correction error rate is used as a new preferential dispersion value, and further dispersion optimization is performed until reaching Presetting the optimization condition, using the current better dispersion value as the optimal dispersion value, and controlling the dispersion adjustment module to perform dispersion retention;

Specifically, the main control module controls the dispersion adjustment module to take one or more dispersion values in both directions of increasing and decreasing the dispersion value with the preferred dispersion value as the center, and the interval between the dispersion values is less than 10 ps/nm (recommended) The value is 5 ps/nm), and is sent to the dispersion adjustment module. After locking, the error rate before error correction is respectively collected, and the dispersion value with the lowest error rate before error correction is used as the new preferred dispersion value, and then The value repeats the above optimization process. The better dispersion value will move to the local error optimal dispersion value according to the system error rate and dispersion curve. The error rate before the error correction of the same dispersion value of the system may change slightly until After a certain termination condition is reached (for example, if the same dispersion value is continuously a better dispersion value, or the adjustment direction of the dispersion value is repeatedly changed), the optimal dispersion value and the corresponding error correction rate before error correction are recorded, and the dispersion retention state is entered.

(4) Maintenance phase

The main control module controls the dispersion adjustment module to perform dispersion retention. At this stage, the main control module controls the dispersion adjustment module not to adjust the dispersion value, and only detects the error count before error correction in real time, so as to reduce the dispersion adjustment module under the condition that the system is basically stable. The number of uses, extending device life.

In addition, preferably, the main control module can collect the optical power of the optical amplifying module in real time, and if the incoming optical power collected by the 低于 is lower than the unlighting threshold, the input control is no light, and the main control module controls the optical amplifying module to be turned off. Light out, and control the dispersion adjustment module to perform dispersion retention. In this way, when the input is not light, the main control module does not release the dispersion adjustment, maintains the original dispersion value, and avoids the original reasonable dispersion value being overwritten, ensuring that the system service transmission is restored immediately after the optical recovery is completed without changing the original line dispersion of the system. .

In addition, the main control module can also control the state transition, including:

(a) When the main control module controls the dispersion adjustment module to perform dispersion retention, if the error count is valid before the error correction is detected, but the error deterioration exceeds the limit (if the error rate is 10 times), and the error is judged to be non-sudden The error code (such as the error degradation overrun lasts for a specified time, such as for 10 seconds), then controls the dispersion adjustment module to perform dispersion optimization.

The error rate before the system error correction becomes larger, indicating that the system has changed and needs to track changes, thus achieving The purpose of tracking. However, the fine-tuning state cannot be entered because the fine-tuned dispersion value search process searches for the dispersion value in both directions to skip the local optimum, and the error count is invalid in both directions, which affects the service signal.

The burst error is instantaneous. If it is quickly restored to the previous state, it does not need to trigger the tracking. According to whether the duration of the error degradation overrun reaches the specified time, for example, lasts for 10 seconds or more, it is determined whether the error is Non-burst error.

(b) When the main control module controls the dispersion adjustment module to perform dispersion optimization or dispersion retention, if the error count before the error correction is detected is invalid and continues for a specified time, the main control module controls the dispersion adjustment module to perform coarse dispersion adjustment; the main control module controls When the dispersion adjustment module performs dispersion fine adjustment, if the error count before the error correction is detected is invalid and continues for a specified time, the initial dispersion error value or the current error correction error corresponding to the current better dispersion value is detected, and if it is invalid, the dispersion adjustment is controlled. The module performs coarse dispersion adjustment, otherwise, it continues to control the dispersion adjustment module to perform dispersion adjustment.

When the dispersion adjustment control algorithm is in a non-coarse adjustment state and the error count is suddenly invalid and lasts for a certain period of time, indicating that the dispersion value of the system has undergone a fundamental change (cutting to another system or a service path protection switching occurs), a new system is required. The re-search of the dispersion value, that is, the control enters the coarse adjustment state and restarts the dispersion value search after confirming the current business state; when the fine adjustment state occurs, the error count is invalid, and it is necessary to distinguish whether the system changes or finds the dispersion tolerance boundary (in the fine adjustment Step), can be distinguished by whether the system stops the error count after the initial dispersion value or the better dispersion value recorded in the fine adjustment process is reissued.

(c) When the main control module controls the dispersion adjustment module to perform coarse dispersion adjustment, if it is detected that the error correction count is valid before the current error correction and the error rate is less than the optimization threshold, the coarse adjustment can be skipped, and the dispersion adjustment module can directly control the dispersion. Optimization

This case is usually the subsequent step of the above case (b), that is, when the main control module controls the dispersion adjustment module to perform dispersion optimization or dispersion retention or dispersion fine adjustment, since the error count before the error correction is invalid and continues to specify the time, When the main control module controls the dispersion adjustment module to perform coarse dispersion adjustment, the system detects that the current dispersion value corresponds to a low error rate before the error correction, and the system status is very good. At this time, the threshold can be optimized according to the set threshold (recommended 1E-6) Or lower) to control whether to enter the optimization stage directly. If the error rate of the current error correction system is low enough, the current dispersion value is acceptable even if the current dispersion value is locally optimal. Then the control algorithm skips directly. Fine-tuning goes directly into the optimization, saving adjustment time and eliminating signal interruptions in up to two boundary searches during fine-tuning. Through the above control algorithm, the main control module can automatically control the dispersion adjustment module to automatically search for the optimal dispersion value that minimizes the error rate before error correction, and adaptive tracking or searching with the system error rate. The dispersion adjustment control algorithm includes solutions to problems such as speed, local optimum, sudden error, and system variation in dispersion adjustment. When higher requirements are put forward in the system, the automatic adjustment algorithm can be combined with more control factors to complete more complex dispersion value adjustment requirements that make the system performance optimal.

Corresponding to the method, the main control module is configured to control the dispersion adjustment module to perform coarse dispersion adjustment, and determine whether the error count before the error correction is valid according to the error correction error detected by the error detection module, and if valid, The current dispersion value is used as the initial dispersion value, and the control dispersion adjustment module performs dispersion fine adjustment; the main control module is further configured to detect, when the dispersion adjustment module performs dispersion adjustment, the initial dispersion value is centered, and the error detection module detects Before the error correction, the error is counted within the effective range search, and the dispersion value corresponding to the error rate before the minimum error correction is used as the better dispersion value, and then the dispersion adjustment module is controlled to perform dispersion optimization; the main control module is also set to control the dispersion adjustment. When the module performs dispersion optimization, one or more dispersion values are taken from each side with a better dispersion value, and the error rate before the error correction is detected by the error detection module, and the minimum error correction error is detected. The dispersion value corresponding to the rate is used as the new preferred dispersion value, and the dispersion optimization is further performed until the preset termination optimization condition is reached. The current preferred dispersion value is taken as the optimum dispersion value, and the dispersion adjustment module is controlled to perform dispersion retention.

The main control module is further configured to: when the dispersion adjustment module performs the dispersion retention, if the error detection module detects that the error correction is valid before the error correction, the error deterioration exceeds the limit, and the error is determined to be non-sudden When the error code is sent, the dispersion adjustment module is controlled to perform dispersion optimization.

The main control module is further configured to: when the dispersion adjustment module performs dispersion optimization or dispersion retention, if the error detection module detects that the error count is invalid before the error correction and continues for a specified time, the main control module controls the dispersion adjustment The module performs a coarse dispersion adjustment; and the main control module is further configured to: when the dispersion adjustment module performs the dispersion fine adjustment, if the error detection module detects that the error correction count is invalid after the error correction and continues for a specified time, The error detection module detects the initial dispersion value or the error before the error correction corresponding to the current better dispersion value, and if not, controls the dispersion adjustment module to execute the color. Coarse coarse adjustment, otherwise, continue to control the dispersion adjustment module to perform dispersion fine adjustment.

Figure 4 is a global diagram of an application example of dispersion adjustment and state change described above. In addition to automatic adjustment without human intervention at all, it also provides manual parameter setting for external intervention, which can be used as a switch option other than automatic control. .

If manual control is added, there is a fixed value setting and a state transition from a fixed value to an automatic search, which requires an algorithmic guarantee. If you can support the external direct setting of the specific dispersion value does not change with the system, or when the error count is invalid, the adjustment state does not directly migrate to the coarse adjustment of the wide range search, but enters the pause, and continuously detects whether other parameters of the system are restored, waiting for the system. Direct recovery after restoration, this is beneficial for the direct recovery of the dispersion-related settings after the known other disturbance factors of the system have changed and recovered, which can greatly save the search time.

After the system is powered on, when the input light (LOS (Loss of Signal) disappears), the optical amplifier module EDFA (Ebium-Doped Fiber Amplifier) outputs fixed optical power, such as +5dBm; After the photoelectric conversion of the optical module is started, the error detection module starts detecting the error code, performs coarse dispersion adjustment, and traverses the global step by a large step of lOOps/nm. When the error count is valid, it goes to the dispersion fine adjustment state, and passes through the middle of 20 ps/nm. The step size performs local traversal, then enters the dispersion optimization state, and searches for the bit error rate of a plurality of points through a pitch of 5 ps/nm. When a better dispersion value remains unchanged for N consecutive times, the dispersion maintaining state is entered. If the error is degraded by X times, then the dispersion optimization state is entered to perform dispersion optimization. When the bit error rate is lower than the threshold A, the optimization state can be directly entered from the coarse adjustment state or the fine adjustment state; when the dispersion value valid for the error count cannot be found, the dispersion adjustment pause state can also be entered. After entering the dispersion hold state, when the bit error rate alarm or bit error rate is higher than the threshold B, and the tracking dispersion small change switch is "continuous", the dispersion adjustment pause state is entered. When in the dispersion adjustment pause state, when the bit error rate is lower than the threshold C, it can directly enter the original working state. When in the dispersion adjustment pause state, the dispersion hold state or the dispersion optimization state, the bit error rate alarm or bit error rate is higher than the threshold A duration T1, and the capture measure switch is "re-search", the dispersion coarse adjustment state is entered. Wherein A can be 1E-5, B can be 1E-3, C can be 1E-3, N can be 2, and X can be 10.

When switching from manual execution to automatic execution or re-issuing the automatic execution command, it means that the dispersion adjustment needs to be restarted, but the execution process is closely related to the current system state. Because the boundary search of the fine-tuning process causes a temporary interruption of the service signal, this is only good for an already stable operation. The system is not allowed. The re-execution of the algorithm starts from the coarse adjustment state. When the current state of the coarse adjustment state check system is not invalid, the error adjustment needs to be selected to enter the fine adjustment or directly enter the optimization. At this time, it is necessary to perform branch selection according to whether the error count of the system state transitions to the coarse adjustment is invalid. If the error count is invalid when entering the coarse adjustment state, it means that the search for the optimal dispersion point is started from the invalid error count, which is a search. The complete process of the optimal dispersion value, the interruption of the service can occur in the middle. In this case, when the effective dispersion point is found in the coarse adjustment, it should enter the fine adjustment state to continue execution; if the error count is valid when entering the coarse adjustment state, the explanation is only It is necessary to perform the re-optimization of the dispersion value on the original system, and no business interruption can occur in the middle, so that the current dispersion point is taken as the starting point, and the optimal state is directly entered, and the search for the optimal dispersion value is continued.

In summary, the present invention can provide necessary dispersion compensation for long-distance transmission and high-rate dispersion-sensitive devices, can effectively adapt to the WDM system, quickly and automatically search for and compensate for residual dispersion values, and avoid finding only local optimums. Anti-system burst error, can track system dispersion change automatically, improve the performance of optical channel access equipment and the anti-interference ability of the WDM system.

One of ordinary skill in the art will appreciate that all or a portion of the above steps may be accomplished by a program that instructs the associated hardware, such as a read-only memory, a magnetic or optical disk, and the like. Alternatively, all or part of the steps of the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module in the foregoing embodiment may be implemented in the form of hardware, or may be implemented in the form of a software function module. The invention is not limited to any particular combination of hardware and software.

It is a matter of course that the invention may be embodied in various other forms and modifications without departing from the spirit and scope of the invention.

INDUSTRIAL APPLICABILITY The method and apparatus for adaptive dispersion compensation provided by the present invention improve the dispersion search speed and accuracy, can eliminate local optimum, filter system sudden disturbance, improve optical channel access equipment and overall system performance, and have good Application prospects and use value.

Claims

Claim

1. A method of adaptive dispersion compensation, comprising:

The main control module controls the dispersion adjustment module to perform coarse dispersion adjustment, and detects the error before the error correction. If the error code is valid before the error correction, the current dispersion value is used as the initial dispersion value, and the dispersion adjustment module is controlled to perform dispersion adjustment;

When the main control module controls the dispersion adjustment module to perform dispersion optimization, one or more dispersion values are taken from each side with a better dispersion value, and the corresponding error correction rate before error detection is detected, and the minimum error correction error detected is detected. The dispersion value corresponding to the code rate is used as a new preferred dispersion value, and the dispersion optimization is further performed until the preset termination optimization condition is reached, the current better dispersion value is taken as the optimal dispersion value, and the dispersion adjustment module is controlled to perform dispersion retention.

2. The method of claim 1 further comprising:

3. The method according to claim 1, wherein the step of the main control module controlling the dispersion adjustment module to perform coarse dispersion adjustment comprises:

The main control module controls the dispersion adjustment module to search in a large step until the error count is valid before detecting the error correction; the step size of the large step is 50 ps/nm ~ 150 ps/nm.

4. The method according to claim 1, wherein the step of the main control module controlling the dispersion adjustment module to perform dispersion fine adjustment comprises:

The main control module controls the dispersion adjustment module to perform the search in the middle step to increase and decrease the dispersion value in the middle step, until the error count is invalid until the error correction is detected; the step of the middle step 10 ps/nm - 30ps/nm

5. The method of claim 1, wherein

6. The method of claim 1 further comprising:

7. The method of any one of claims 1 to 6, further comprising:

When the main control module controls the dispersion adjustment module to perform dispersion optimization or dispersion retention, if the error count before the error correction is detected to be invalid and continues for a specified time, the main control module controls the dispersion adjustment module to perform coarse dispersion adjustment;

8. The method of claim 7 further comprising:

9. An apparatus for adaptive dispersion compensation, comprising an optical amplification module, a circulator, an error detection module, a dispersion adjustment module, and a main control module, wherein

The optical amplifying module is configured to output the input light to the dispersion by a constant optical power through the circulator Entire module

The main control module is configured to control the dispersion adjustment module to perform coarse dispersion adjustment, and determine whether the error count before the error correction is valid according to the error correction error detected by the error detection module, and if valid, the current dispersion value As the initial dispersion value, the control dispersion adjustment module performs dispersion fine adjustment; the main control module is further configured to detect the error correction detected by the error detection module when the dispersion adjustment module performs the dispersion fine adjustment, with the initial dispersion value as the center. The front error code counts the effective range search, and the dispersion value corresponding to the minimum error correction error rate is used as the better dispersion value, and then the dispersion adjustment module is controlled to perform dispersion optimization; the main control module is further configured to perform dispersion at the control dispersion adjustment module. During optimization, one or more dispersion values are taken from each side with the preferred dispersion value as the center, and the error rate before the error correction is detected by the error detection module, and the detected error rate before the minimum error correction is corresponding. The dispersion value is used as the new better dispersion value, and the dispersion optimization is further performed until the preset termination optimization condition is reached, and the current comparison is performed. The dispersion value as the optimal dispersion values and the dispersion adjustment module performs the control to maintain the dispersion.

10. The apparatus according to claim 9, wherein

The main control module is further configured to set the optical power of the concentrating and amplifying module. If the illuminating power of the concentrating light is lower than the unlighting threshold, the input light is judged to be no light, the optical amplifying module is controlled to turn off the light, and the dispersion adjusting module is controlled. Perform dispersion retention.