Method for implementing signal-to-noise ratio reporting function based on CDR solution, and optical module

Abstract

The present invention relates to the technical field of optical communications and particularly relates to a method for implementing a signal-to-noise ratio reporting function based on a CDR solution, and an optical module. In the present invention, eye diagram data is obtained by means of scanning data in a communication link, and after the eye diagram data is processed, the average value thereof is obtained, so as to obtain a signal-to-noise ratio value to be reported, thereby achieving SNR reporting of the optical module based on the CDR solution, effectively improving the accuracy and stability of the SNR reporting, enabling the optical module based on the CDR solution to also effectively measure the link SNR indicator health status, and providing an effective test method and means for testing the chromatic dispersion of the optical module, investigating the influence of temperature and MPI on the SNR, and the like. In addition, a bit error rate can also be reduced by guiding the configuration of FEC correction and equalization compensation, thereby improving the quality of signal transmission.

Description

A method and optical module for implementing signal-to-noise ratio (SNR) reporting based on CDR scheme.

[0001] Cross-reference of related applications

[0002] This application claims priority to the following patent application:

[0003] (1) A Chinese patent application filed with the Chinese Patent Office on August 30, 2024, with application number 202411212311.4 and titled "A method and optical module for realizing signal-to-noise ratio reporting function based on CDR scheme". Technical Field

[0004] This invention relates to the field of optical communication technology, and in particular to a method and optical module for implementing signal-to-noise ratio reporting based on a CDR scheme. Background Technology

[0005] With the continuous increase in the number of antennas and air interface bandwidth in 5G communications, the demand for 50G optical modules is also increasing. Pulse Amplitude Modulation (PAM) technology has been widely used in wireless fronthaul communication systems due to its high spectral efficiency and low system complexity. However, PAM signals are sensitive to noise and interference, and the effects of system dispersion and multipath interference need to be considered. Therefore, it is urgent to monitor the signal-to-noise ratio (SNR) of optical modules in real time.

[0006] Currently, there are two main technical solutions for 50G optical modules: Clock and Data Recovery (CDR) and Digital Signal Processing (DSP). CDR offers advantages in low latency, low power consumption, and rate compatibility, effectively meeting the critical requirements of wireless fronthaul scenarios. However, in terms of algorithms and signal sampling capabilities, CDR technology lacks the strength of DSP, as it cannot directly sample PAM signals. Therefore, CDR solutions typically lack the complex algorithms and processing capabilities required to calculate the optical module's SNR.

[0007] Therefore, overcoming the shortcomings of the existing technology is an urgent problem to be solved in this technical field.

[0008] Application content

[0009] The technical problem to be solved by this invention is how to calculate and report the signal-to-noise ratio of an optical module that uses CDR technology.

[0010] The present invention adopts the following technical solution:

[0011] Firstly, a method for implementing signal-to-noise ratio (SNR) reporting based on a CDR scheme is provided, including:

[0012] Eye diagram scanning is performed on the channels in the communication link to obtain eye diagram data;

[0013] The eye diagram data is processed, and the eye diagram signal-to-noise ratio value is obtained based on the processed eye diagram data;

[0014] After obtaining the eye diagram signal-to-noise ratio (SNR) values ​​for a preset number of times, the average value is taken to obtain the reported SNR value.

[0015] Preferably, the step of performing an eye diagram scan on the channels in the communication link to obtain eye diagram data includes:

[0016] After the optical module detects the signal-to-noise ratio calculation command, it determines whether there are any changes in the temperature and / or input power reported by the optical module.

[0017] If the temperature and / or input power reported by the optical module remain unchanged, the eye diagram data is obtained by performing an eye diagram scan of the channel in the communication link for a preset duration using the CDR chip.

[0018] If the optical module reports a change in temperature and / or input power, after waiting for a preset delay time, the CDR chip performs an eye diagram scan of the channel in the communication link for a preset duration to obtain the eye diagram data.

[0019] Preferably, the step of processing the eye diagram data and obtaining the eye diagram signal-to-noise ratio value based on the processed eye diagram data includes:

[0020] The eye diagram data is analyzed to obtain multiple levels, and the levels are analyzed using a distribution histogram to obtain the level distribution; wherein each level includes at least one level data.

[0021] Based on the level distribution, the mean and standard deviation around the mean are obtained for each level.

[0022] The eye diagram signal-to-noise ratio value is obtained based on the mean and the standard deviation around the mean.

[0023] Preferably, obtaining the mean and standard deviation around the mean for each level based on the level distribution includes:

[0024] The mean value for each level is calculated as follows: μ = average(level_data)

[0025] The standard deviation to the left of the mean is calculated as: σ 左 = std(level_data(<μ))

[0026] The standard deviation to the right of the mean is calculated as: σ 右 = std(level_data(>μ))

[0027] Where μ is the mean value for each level, average() calculates the mean, std() calculates the standard deviation, level_data represents the level data for each level, and σ 左 σ represents the standard deviation to the left of the mean. 右 It represents the standard deviation to the right of the mean.

[0028] Preferably, obtaining the eye diagram signal-to-noise ratio value based on the mean and the standard deviation around the mean includes:

[0029] The eye diagram SNR of the PAM signal is calculated based on the mean and the standard deviation around the mean, and the worst signal-to-noise ratio among the eye diagram SNRs is taken to obtain the overall signal-to-noise ratio value.

[0030] The overall signal-to-noise ratio is calibrated to obtain the eye diagram signal-to-noise ratio.

[0031] Preferably, the formula for calculating the SNR of the eye diagram is:

[0032] When the PAM signal is a PAM4 signal, the formula for calculating the overall signal-to-noise ratio (SNR) is: SNR CMIS =10log 10 (min{SNR0, SNR1, SNR2})

[0033] Where SNR is the eye diagram SNR, μx is the mean of the next level, and μy is the mean of the previous level.

[0034] σm is the standard deviation to the right of the mean of the previous level, and σn is the standard deviation to the left of the mean of the next level. SNR CMIS Let SNR be the overall signal-to-noise ratio, SNR0, SNR1, and SNR2 be the eye diagram SNR, and min{} denotes finding the minimum value.

[0035] Preferably, calibrating the overall signal-to-noise ratio value to obtain the eye diagram signal-to-noise ratio value includes:

[0036] Where SNR* is the eye diagram signal-to-noise ratio value, and M is the modulation level number, such as M=4 for PAM4.

[0037] Preferably, the method further includes:

[0038] Under different temperature conditions, the bit error rate was statistically analyzed for each received optical power point of the test sample, and the test signal-to-noise ratio value corresponding to each bit error rate was read.

[0039] Based on the bit error rate and the corresponding test signal-to-noise ratio (SNR) values, construct SNR-bit error rate curves under different temperature conditions;

[0040] By comparing the signal-to-noise ratio (SNR)-bit error rate (BER) curves under different temperature conditions with the standard curve, a mapping relationship between temperature conditions, BER range, and compensation value is established, so as to compensate the reported SNR value according to the mapping relationship.

[0041] Preferably, the bit error rate requirement of the optical module is obtained;

[0042] When the required bit error rate is within the first bit error rate range, there is no need to adjust the reported signal-to-noise ratio value; the reported signal-to-noise ratio value is reported.

[0043] When the bit error rate requirement is within the second bit error rate range, the reported temperature of the optical module is obtained, and the corresponding compensation value is obtained from the mapping relationship based on the reported temperature and the bit error rate requirement.

[0044] The reported signal-to-noise ratio (SNR) value is compensated based on the obtained compensation value to obtain a new reported SNR value.

[0045] In a second aspect, an optical module is provided for implementing the signal-to-noise ratio reporting function based on the CDR scheme as described in the first aspect. The optical module includes a CDR chip and a processor. The CDR chip is used to perform eye diagram scanning on the channels in the communication link to obtain eye diagram data.

[0046] The processor is used to process the eye diagram data, obtain the eye diagram signal-to-noise ratio (SNR) value based on the processed eye diagram data, and obtain the average value of the eye diagram SNR values ​​after obtaining a preset number of times to obtain the reported SNR value.

[0047] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0048] This invention achieves SNR reporting for optical modules based on the CDR scheme by scanning data in the communication link to obtain eye diagram data, processing the eye diagram data, and averaging the values ​​to obtain the reported signal-to-noise ratio (SNR). This effectively improves the accuracy and stability of SNR reporting, allowing CDR-based optical modules to effectively measure the health of the link's SNR. It provides effective testing methods and means for testing optical module dispersion, exploring the impact of temperature and multi-path interference (MPI) on SNR, and further improving signal transmission quality by guiding the configuration of forward error correction (FEC) and equalization compensation to reduce the bit error rate. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 is a flowchart illustrating a method for implementing signal-to-noise ratio reporting based on a CDR scheme according to an embodiment of the present invention;

[0051] Figure 2 is a schematic diagram of eye diagram data provided in an embodiment of the present invention;

[0052] Figure 3 is a schematic diagram of a process for obtaining the eye diagram signal-to-noise ratio value according to an embodiment of the present invention;

[0053] Figure 4 is a histogram diagram of eye diagram data provided in an embodiment of the present invention;

[0054] Figure 5 is a schematic diagram of a specific process for obtaining the eye diagram signal-to-noise ratio value according to an embodiment of the present invention;

[0055] Figure 6 is a schematic diagram of an eye diagram SNR provided in an embodiment of the present invention;

[0056] Figure 7 is a schematic diagram of a process for correcting the reported signal-to-noise ratio value according to an embodiment of the present invention;

[0057] Figure 8 is a schematic diagram of SNR example test data of a sample provided in an embodiment of the present invention;

[0058] Figure 9 is a schematic diagram of a signal-to-noise ratio-bit error rate curve provided in an embodiment of the present invention;

[0059] Figure 10 is a schematic diagram of a modified signal-to-noise ratio-bit error rate curve provided by an embodiment of the present invention. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0061] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as openly inclusive, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiment," "example," "specific example," or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples; that is, although they may be incorporated into embodiments or examples using the above terms for reasons such as order and position, it does not limit them to be incorporated in combination by a single embodiment or example.

[0062] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more. Furthermore, for example, the description may use the prefix "A" or "B" to describe the same type of nouns as two independent entities. In this case, the corresponding features defined with "A" and "B" are used only to distinguish between similar entities and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0063] In describing some embodiments, the terms "coupled," "coupled," and "connected," and their derivative expressions, may be used. For example, the term "connected" may be used in describing some embodiments to indicate that two or more components have direct physical or electrical contact with each other. Similarly, the term "coupled" may be used in describing some embodiments to indicate that two or more components have direct physical or electrical contact. However, the terms "connected" or "coupled" may also refer to two or more components that do not have direct contact with each other but still cooperate or interact with each other, such as "optical coupling," "wireless connection," etc. The embodiments disclosed herein are not necessarily limited to the scope of this invention.

[0064] Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0065] Example 1:

[0066] Optical modules based on the CDR (Clock Recovery Diagram) scheme can achieve high-speed data transmission in optical communication systems. The key to the CDR scheme lies in the integration of a clock recovery circuit, which enables the optical module to accurately recover the data and clock signals from the transmitting end, thereby ensuring the synchronization and reliability of data transmission.

[0067] Its working principle typically includes:

[0068] 1. Photoelectric conversion: The transmitting end of the optical module converts electrical signals into optical signals, which are then transmitted through optical fiber. The receiving end then converts the optical signals back into electrical signals.

[0069] 2. Clock Recovery: At the receiving end, the CDR chip extracts clock information from the received data signal. This clock information is synchronized with the clock at the transmitting end. Thus, even if the data signal and clock signal are separated during transmission due to fiber optic delay or other factors, the CDR chip can resynchronize them.

[0070] 3. Data Processing: The synchronized data signal can be sent to the data processing unit for further processing and analysis.

[0071] The CDR scheme can handle data rates of tens or even hundreds of Gbps, meeting the needs of high-speed communication. By restoring the clock signal, the CDR scheme can ensure the synchronization of data transmission and reduce transmission errors caused by clock out-of-sync. The CDR scheme can compensate for signal attenuation and distortion during optical fiber transmission, improve signal stability, and at the same time, through precise clock recovery, the CDR scheme can reduce the bit error rate and improve the reliability of data transmission.

[0072] With the continuous development of optical modules, real-time monitoring of the signal-to-noise ratio (SNR) of optical modules is becoming increasingly important. However, in terms of algorithms and signal sampling capabilities, CDR-based schemes typically lack the ability to calculate and process the SNR. To address this issue, Embodiment 1 of this invention provides a method for implementing SNR reporting based on a CDR scheme, comprising: performing eye diagram scanning on the channels in the communication link to obtain eye diagram data; processing the eye diagram data and obtaining an eye diagram SNR value based on the processed eye diagram data; and averaging the eye diagram SNR values ​​obtained a preset number of times to obtain the reported SNR value.

[0073] Eye diagrams display the amplitude of a signal over time, providing a visual representation of high and low signal levels, rise and fall times, and the overall shape of the signal. Processed eye diagram data can be used to calculate the signal-to-noise ratio (SNR), the ratio of signal power to noise power. The eye diagram SNR value reflects the ratio between effective information in the signal and background noise. To improve the stability and reliability of the SNR value, multiple measurements are performed, resulting in a series of eye diagram SNR values. The average of these multiple measurements is then used as the overall performance indicator of the communication link. This average value can be reported as the SNR value for monitoring and evaluating the quality of the communication link.

[0074] The following will describe in detail the steps of the method for implementing the signal-to-noise ratio reporting function based on the CDR scheme, as shown in Figure 1. The method includes:

[0075] Step 101: Perform an eye diagram scan on the channels in the communication link to obtain eye diagram data.

[0076] Specifically, step 101 includes: after the optical module detects the signal-to-noise ratio calculation command, determining whether there is a change in the temperature and / or input power reported by the optical module; if there is no change in the temperature and / or input power reported by the optical module, performing an eye diagram scan of the channel in the communication link for a preset duration through the CDR chip to obtain the eye diagram data; if there is a change in the temperature and / or input power reported by the optical module, waiting for a preset delay time, and then performing an eye diagram scan of the channel in the communication link for a preset duration through the CDR chip to obtain the eye diagram data.

[0077] In one embodiment, as shown in Figure 2, when the optical module receives a signal-to-noise ratio (SNR) calculation instruction, it guides the CDR chip to begin data acquisition. According to the optical module's instructions, the CDR chip acquires eye diagram data for a preset duration. The preset duration can be set according to actual conditions and is not limited in this embodiment.

[0078] In one embodiment, changes in the reported temperature and input power of the optical module can be continuously monitored during its operation. Changes in these parameters affect the performance and signal-to-noise ratio (SNR) of the optical module. If any change in temperature or input power is detected, a preset delay time (e.g., 60 seconds) is added. This delay time is intended to allow the optical module to stabilize, as temperature changes and input power fluctuations can alter the internal state of the optical module. After the preset delay time, if there are no changes in the reported temperature and / or input power, the optical module will then acquire eye diagram data via the CDR chip. This ensures that the reported SNR is based on the latest and stable system state. In this way, even if fluctuations in reported temperature or input power occur during the operation of the optical module, the stability of the communication link environment and bit error rate can be guaranteed, thus ensuring the accuracy of the final SNR report. The preset delay time can be set according to actual conditions and is not specifically limited in this embodiment.

[0079] Step 102: Process the eye diagram data and obtain the eye diagram signal-to-noise ratio value based on the processed eye diagram data.

[0080] In one embodiment, as shown in Figure 3, taking the optical module communicating via PAM4 modulation technology as an example, step 102 specifically includes:

[0081] Step 1021: Analyze the eye diagram data to obtain multiple levels, and perform distribution histogram analysis on the levels to obtain the level distribution. Each level includes at least one level data point.

[0082] As shown in Figure 4, the optical module reads information from the eye diagram data obtained from the CDR chip and generates a level distribution histogram. In the level distribution histogram, P represents the peak height, where the peak of a normal distribution appears at the maximum value of the probability density function; V represents the valley height, referring to the relatively low probability density region in the histogram. The level distribution histogram shows the change of signal level over time and can be used to analyze the signal level distribution. When the optical module communicates using PAM4 modulation technology, this embodiment uses PAM4 signal as an example (this embodiment also supports PAM5 and PAM16 signals, but they are not as widely used as PAM4 at present). In one embodiment, since the PAM4 signal uses four different signal levels for signal transmission, each symbol period can represent 2 bits of logical information (0, 1, 2, 3). Therefore, the resulting histogram includes four level levels (P0, P1, P2, and P3).

[0083] Step 1022: Based on the level distribution, obtain the mean and standard deviation around the mean for each level.

[0084] The optical module uses histogram analysis to obtain the mean (i.e., average amplitude) and standard deviation around the mean for each level. Standard deviation is a measure of the dispersion of data distribution and helps determine the stability and noise level of the levels. The mean for each level is calculated as: μ = average(level_data)

[0085] The standard deviation to the left of the mean is calculated as: σ 左 = std(level_data(<μ))

[0086] The standard deviation to the right of the mean is calculated as: σ 右 = std(level_data(>μ))

[0087] Where μ is the mean value for each level, average() calculates the mean, std() calculates the standard deviation, level_data represents the level data for each level, and σ 左 σ represents the standard deviation to the left of the mean. 右 It represents the standard deviation to the right of the mean.

[0088] Referring to Figure 4, the means for the four levels are μ0, μ1, μ2, and μ3, respectively. The standard deviation to the left of μ0 is σ. 0+ (Not shown in the figure), the standard deviation to the right of μ0 is σ0; the standard deviation to the left of μ1 is σ 1+ The standard deviation to the right of μ1 is σ1; the standard deviation to the left of μ2 is σ. 2+ The standard deviation to the right of μ2 is σ2; ​​the standard deviation to the left of μ3 is σ. 3+ The standard deviation to the right of μ3 is σ3.

[0089] Step 1023: Obtain the eye diagram signal-to-noise ratio value based on the mean and the standard deviation around the mean.

[0090] In one embodiment, the SNR of the three eye diagrams of the PAM4 signal is calculated separately. The worst SNR is taken to calculate the overall SNR value. Then, it is calibrated using a set of first-order calibration coefficients in the optical module register (A2H Page 04H byte 86-89) to obtain the final eye diagram SNR value, which is stored in the optical module register (A2H Page 03H byte 203-206). When the link is broken (i.e., LOL = 1 at the optical module receiver), the optical signal is lost at the optical module receiver, and the optical module reports an SNR of 0x00.

[0091] In one embodiment, as shown in FIG5, step 1023 specifically includes:

[0092] Step 10231: Calculate the eye diagram SNR of the PAM signal based on the mean and the standard deviation around the mean, and take the worst SNR of the eye diagram to obtain the overall SNR value.

[0093] The formula for calculating the SNR of the eye diagram is as follows:

[0094] Referring to Figures 4 and 6, three eye diagrams SNR (SNR0, SNR1, and SNR2) are obtained based on the four levels in Figure 3. SNR0, SNR1, and SNR2 correspond to the bottom, middle, and top eye diagrams in Figure 6, respectively.

[0095] In one embodiment, when the PAM signal is a PAM4 signal, the formula for calculating the overall signal-to-noise ratio (SNR) is: SNR CMIS =10log 10 (min{SNR0, SNR1, SNR2})

[0096] Where SNR is the eye diagram SNR, μx is the mean of the next level, and μy is the mean of the previous level.

[0097] σm is the standard deviation to the right of the mean of the previous level, and σn is the standard deviation to the left of the mean of the next level. SNR CMIS Let SNR be the overall signal-to-noise ratio, SNR0, SNR1, and SNR2 be the eye diagram SNR, and min{} denotes finding the minimum value.

[0098] Step 10232: Calibrate the overall signal-to-noise ratio value to obtain the eye diagram signal-to-noise ratio value.

[0099] Specifically, in one embodiment, the overall signal-to-noise ratio (SNR) is calibrated using a set of first-order calibration coefficients in the optical module register to obtain the eye diagram SNR. The formula for calculating the eye diagram SNR is as follows:

[0100] Where SNR* is the eye diagram signal-to-noise ratio value, and M is the modulation level number, such as M=4 for PAM4.

[0101] Step 103: After obtaining the eye diagram signal-to-noise ratio values ​​of a preset number of times, take the average value to obtain the reported signal-to-noise ratio value.

[0102] In order to reduce the error of the test, the signal-to-noise ratio can be calculated multiple times and then weighted and averaged (e.g., 10 times). Finally, this average value is used as the reported signal-to-noise ratio value for monitoring and evaluating the quality of the communication link of the optical module.

[0103] Bit error rate (BER) is the ratio of the number of bits that err during data transmission to the total number of bits transmitted, while signal-to-noise ratio (SNR) is the ratio of signal power to noise power.

[0104] Bit Error Rate (BER) = (Number of erroneous bits / Total number of transmitted bits). The lower the BER, the fewer erroneous bits are transmitted, and the better the communication quality.

[0105] Signal-to-noise ratio (SNR) = (signal power / noise power). The higher the SNR, the greater the ratio of signal power to noise power, and the better the communication quality is usually.

[0106] Under given modulation schemes and transmission channels, there is a direct relationship between bit error rate (BER) and signal-to-noise ratio (SNR). Generally, as the SNR increases, the BER decreases. This is because a higher SNR means a greater difference between the signal and noise, making it easier for the receiver to correctly determine the signal value, thus reducing errors. In simple amplitude modulation systems, there may be a more direct relationship between BER and SNR: the higher the SNR, the lower the BER.

[0107] In one embodiment, to ensure more accurate reporting of the signal-to-noise ratio (SNR), the test sample needs to be tested beforehand to obtain compensation values ​​under different temperatures and bit error rates (BER) ranges. This establishes a mapping relationship between temperature conditions, BER ranges, and compensation values. In practical use, the SNR is compensated based on this pre-established mapping relationship. As shown in Figure 7, the method further includes:

[0108] Step 201: Under different temperature conditions, perform bit error rate statistics for each received optical power point of the test sample, and read the test signal-to-noise ratio value corresponding to each bit error rate.

[0109] Here, "different temperature conditions" refers to low temperature conditions, room temperature regulation, and high temperature conditions. The test signal-to-noise ratio (SNR) value refers to the reported SNR value of the test sample. A bit error rate (BER) meter is typically used to test the performance of optical modules under different received optical powers. In the BER meter's cumulative mode, the number of erroneous bits received within a certain time period is counted, usually within a specific time window. For each received optical power point (let the optical power step values ​​of the optical module be: 1dB, 0.5dB, 0.3dB, 0.2dB, 0.1dB), the corresponding bit error rate (BER) is calculated, which is the ratio of erroneous bits to the total number of bits. After calculating the BER, the reported SNR values ​​obtained through steps 101-103 are read and matched one-to-one (i.e., one BER corresponds to one reported SNR value).

[0110] Step 202: Construct signal-to-noise ratio-bit error rate curves under different temperature conditions based on the bit error rate and the corresponding test signal-to-noise ratio values.

[0111] Based on the bit error rate and reported signal-to-noise ratio (SNR) values ​​collected in step 201, SNR-bit error rate curves are plotted under different temperature conditions. These three curves illustrate the bit error rate performance of the optical module under different SNRs. Typically, a standard curve is used as a reference, representing the relationship between bit error rate and SNR under ideal conditions.

[0112] Step 203: Compare the signal-to-noise ratio-bit error rate curves under different temperature conditions with the standard curve, and establish a mapping relationship between temperature conditions, bit error rate range and compensation value, so as to compensate the reported signal-to-noise ratio value according to the mapping relationship.

[0113] In one embodiment, Figure 8 shows an example of SNR instance test data for sample 934# (i.e., the test sample), and Figure 9 shows the signal-to-noise ratio (SNR)-bit error rate (BER) curve depicted thereon: where the horizontal axis represents the signal-to-noise ratio (SNR) and the vertical axis represents the BER. LT represents the SNR-BER curve under low temperature conditions (approximately -40°C), RT represents the SNR-BER curve under normal temperature conditions (approximately 25°C), HT represents the SNR-BER curve under high temperature conditions (approximately 85°C), and the smoother curve is the standard curve.

[0114] As shown in Figures 8 and 9, when the bit error rate (BER) is in the range of 1E-7 to 1E-4, the difference in SNR between the test and standard curves is within 0 to ±0.3, indicating good consistency. However, when the BER is in the range of 1E-7 to 1E-13, the difference in SNR exceeds 0.5 dB, meaning that within a 1 dB SNR at high optical power, the BER may span 4 to 5 orders of magnitude, requiring further improvement in the stability of SNR below 1E-7.

[0115] In one embodiment, using a BER close to 1E-7 as a benchmark, the SNR values ​​of the signal-to-noise ratio (SNR)-bit error rate (BER) curves under three temperature conditions in Figure 8 are compared with those of the standard curve. The offsets (i.e., compensation values) under low temperature, normal temperature, and high temperature conditions are obtained as 0.26, 0.41, and 0.32, respectively, thus establishing a mapping relationship. In another embodiment, the BER < 1E-7 interval is corrected for SNR according to the offsets under the three temperature conditions, and the corrected SNR-BER curve is shown in Figure 10.

[0116] Therefore, in order to further improve the accuracy of signal-to-noise ratio reporting, the mapping relationship can be determined based on temperature conditions, bit error rate range, and compensation value.

[0117] In one embodiment, the process of compensating the reported signal-to-noise ratio (SNR) value according to the mapping relationship specifically includes: obtaining the bit error rate (BER) requirement of the optical module; when the BER requirement is within a first BER range, no adjustment is needed to the reported SNR value, and the reported SNR value is reported; when the BER requirement is within a second BER range, the reported temperature of the optical module is obtained, and a corresponding compensation value is obtained from the mapping relationship based on the reported temperature and the BER requirement; the reported SNR value is compensated based on the obtained compensation value to obtain a new reported SNR value.

[0118] The bit error rate interval may include at least a first bit error rate interval and a second bit error rate interval, wherein the lower limit of the first bit error rate interval is greater than or equal to the upper limit of the second bit error rate interval. The bit error rate interval may also include a third bit error rate interval, a fourth bit error rate interval, and more bit error rate intervals. The range of each bit error rate interval can be determined based on the actual measured data and the results of multiple experiments, and is not specifically limited in this embodiment.

[0119] In one embodiment, the difference between the reported signal-to-noise ratio (SNR) corresponding to the bit error rate (BER) and the theoretical SNR varies at different temperatures. Therefore, the impact of temperature needs to be considered comprehensively during SNR compensation. When the BER is within the second BER range, the reported SNR corresponding to the BER within the second BER range is obtained.

[0120] In one embodiment, the first bit error rate (BER) range is 1E-7 to 1E-4, and the second BER range is 1E-13 to 1E-7. The lower limit of the first BER range is 1E-7, and the upper limit of the second BER range is 1E-7. When the BER is greater than 1E-7, the reported signal-to-noise ratio (SNR) value is reported without adjustment. When the BER is less than 1E-7, the reported temperature of the optical module is obtained, and a corresponding compensation value is obtained from the mapping relationship based on the reported temperature and the BER requirement. The reported SNR value is then compensated based on the obtained compensation value to obtain a new reported SNR value.

[0121] This embodiment obtains eye diagram data by scanning the data in the communication link, processes the eye diagram data, and takes the average value to obtain the reported signal-to-noise ratio (SNR) value. This realizes SNR reporting of optical modules based on the CDR scheme and effectively improves the accuracy and stability of the SNR reporting. It also allows optical modules based on the CDR scheme to effectively measure the health status of the link SNR index. This provides an effective testing method and means for testing optical module dispersion and exploring the impact of temperature and MPI on SNR. At the same time, it can also reduce the bit error rate by guiding the configuration of FEC error correction and equalization compensation, thereby improving the quality of signal transmission.

[0122] Example 2:

[0123] In Example 1, a method for implementing signal-to-noise ratio (SNR) reporting based on a CDR scheme was proposed. In this example, an optical module is proposed, which includes a CDR chip and a processor. The CDR chip is used to perform eye diagram scanning on the channel in the communication link to obtain eye diagram data. The processor is used to process the eye diagram data and obtain the eye diagram SNR value based on the processed eye diagram data, and to obtain the average value of the eye diagram SNR values ​​after obtaining a preset number of times to obtain the reported SNR value.

[0124] For the specific steps of the method for implementing the signal-to-noise ratio reporting function based on the CDR scheme, please refer to Example 1, which will not be repeated in this example.

[0125] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for implementing signal-to-noise ratio (SNR) reporting based on a CDR scheme, characterized in that, include: Eye diagram scanning is performed on the channels in the communication link to obtain eye diagram data; The eye diagram data is processed, and the eye diagram signal-to-noise ratio value is obtained based on the processed eye diagram data; After obtaining the eye diagram signal-to-noise ratio values ​​for a preset number of times, the average value is taken to obtain the reported signal-to-noise ratio value.

2. The method for implementing signal-to-noise ratio reporting based on the CDR scheme according to claim 1, characterized in that, The step of performing an eye diagram scan on the channels in the communication link to obtain eye diagram data includes: After the optical module detects the signal-to-noise ratio calculation command, it determines whether there are any changes in the temperature and / or input power reported by the optical module. If the temperature and / or input power reported by the optical module remain unchanged, the eye diagram data is obtained by performing an eye diagram scan of the channel in the communication link for a preset duration using the CDR chip. If the optical module reports a change in temperature and / or input power, after waiting for a preset delay time, the CDR chip performs an eye diagram scan of the channel in the communication link for a preset duration to obtain the eye diagram data.

3. The method for implementing signal-to-noise ratio reporting based on the CDR scheme according to claim 1, characterized in that, The process of processing the eye diagram data and obtaining the eye diagram signal-to-noise ratio value based on the processed eye diagram data includes: The eye diagram data is analyzed to obtain multiple levels, and the levels are analyzed using a distribution histogram to obtain the level distribution; wherein each level includes at least one level data. Based on the level distribution, the mean and standard deviation around the mean are obtained for each level. The eye diagram signal-to-noise ratio value is obtained based on the mean and the standard deviation around the mean.

4. The method for implementing signal-to-noise ratio reporting based on the CDR scheme according to claim 3, characterized in that, When the optical module communicates using PAM4 modulation technology, the PAM4 signal uses four different signal levels for signal transmission. Each symbol period represents two bits of logical information, and the resulting distribution histogram includes four levels.

5. The method for implementing signal-to-noise ratio reporting based on the CDR scheme according to claim 3, characterized in that, The process of obtaining the mean and standard deviation around the mean for each level based on the level distribution includes: The mean value for each level is calculated as follows: μ = average(level_data) The standard deviation to the left of the mean is calculated as follows: σ 左 =std(level_data(<μ)) The standard deviation to the right of the mean is calculated as follows: σ 右 =std(level_data(>μ)) Where μ is the mean value for each level, average() calculates the mean, std() calculates the standard deviation, level_data represents the level data for each level, and σ 左 σ represents the standard deviation to the left of the mean. 右 It represents the standard deviation to the right of the mean.

6. The method for implementing signal-to-noise ratio reporting based on the CDR scheme according to claim 3, characterized in that, The process of obtaining the eye diagram signal-to-noise ratio value based on the mean and the standard deviation around the mean includes: The eye diagram SNR of the PAM signal is calculated based on the mean and the standard deviation around the mean, and the worst signal-to-noise ratio among the eye diagram SNRs is taken to obtain the overall signal-to-noise ratio value. The overall signal-to-noise ratio is calibrated to obtain the eye diagram signal-to-noise ratio.

7. The method for implementing signal-to-noise ratio reporting based on the CDR scheme according to claim 6, characterized in that, The process of obtaining the eye diagram signal-to-noise ratio value based on the mean and the standard deviation around the mean includes: When the optical module communicates using PAM4 modulation technology, the SNR of the three eye diagrams of the PAM4 signal is calculated respectively, and the worst SNR is taken to calculate the overall SNR value. The final eye diagram signal-to-noise ratio (SNR) value is obtained by calibrating a set of first-order calibration coefficients in the optical module register and stored in the optical module A2H Page 03H byte 203~206 register; when the link is broken, the optical signal at the optical module receiver is lost, and the optical module reports an SNR of 0x00.

8. The method for implementing signal-to-noise ratio reporting based on the CDR scheme according to claim 6, characterized in that, The formula for calculating the SNR of the eye diagram is as follows: When the PAM signal is a PAM4 signal, the formula for calculating the overall signal-to-noise ratio is: SNR CMIS =10log 10 (min{SNR0, SNR1, SNR2}) Where SNR is the eye diagram SNR, μx is the mean of the next level, and μy is the mean of the previous level. σm is the standard deviation to the right of the mean of the previous level, and σn is the standard deviation to the left of the mean of the next level. SNR CMIS Let SNR be the overall signal-to-noise ratio, SNR0, SNR1, and SNR2 be the eye diagram SNR, and min{} denotes finding the minimum value.

9. The method for implementing signal-to-noise ratio reporting function based on CDR scheme according to claim 8, characterized in that, The calibration of the overall signal-to-noise ratio value to obtain the eye diagram signal-to-noise ratio value includes: Where SNR* is the eye diagram signal-to-noise ratio value, and M is the modulation level number, such as M=4 for PAM4.

10. The method for implementing signal-to-noise ratio reporting function based on CDR scheme according to claim 1, characterized in that, The method further includes: in order to make the reported signal-to-noise ratio more accurate, testing the test sample in advance to obtain compensation values ​​under different temperatures and different bit error rate ranges; Establish a mapping relationship between temperature conditions, bit error rate range, and compensation values; The signal-to-noise ratio is compensated by a pre-established mapping relationship.

11. The method for implementing signal-to-noise ratio reporting based on the CDR scheme according to claim 10, characterized in that, The method further includes: Under different temperature conditions, the bit error rate was statistically analyzed for each received optical power point of the test sample, and the test signal-to-noise ratio value corresponding to each bit error rate was read. Based on the bit error rate and the corresponding test signal-to-noise ratio (SNR) values, construct SNR-bit error rate curves under different temperature conditions; By comparing the signal-to-noise ratio (SNR)-bit error rate (BER) curves under different temperature conditions with the standard curve, a mapping relationship between temperature conditions, BER range, and compensation value is established, so as to compensate the reported SNR value according to the mapping relationship.

12. The method for implementing signal-to-noise ratio reporting based on the CDR scheme according to claim 11, characterized in that, Different temperature conditions refer to low temperature conditions, normal temperature regulation, and high temperature conditions.

13. The method for implementing signal-to-noise ratio reporting based on the CDR scheme according to claim 11, characterized in that, The step of compensating the reported signal-to-noise ratio value according to the mapping relationship includes: Obtain the bit error rate requirement of the optical module; When the required bit error rate is within the first bit error rate range, there is no need to adjust the reported signal-to-noise ratio value; the reported signal-to-noise ratio value is reported. When the bit error rate requirement is within the second bit error rate range, the reported temperature of the optical module is obtained, and the corresponding compensation value is obtained from the mapping relationship based on the reported temperature and the bit error rate requirement. The reported signal-to-noise ratio (SNR) value is compensated based on the obtained compensation value to obtain a new reported SNR value.

14. The method for implementing signal-to-noise ratio reporting based on the CDR scheme according to claim 13, characterized in that, The lower limit of the first bit error rate interval is greater than or equal to the upper limit of the second bit error rate interval; The bit error rate range also includes a third bit error rate range, a fourth bit error rate range, or more bit error rate ranges; the range of each bit error rate range can be determined based on the actual measured data and the results of multiple experiments.

15. An optical module, characterized in that, The optical module is used to implement the signal-to-noise ratio reporting function based on the CDR scheme as described in any one of claims 1-14, wherein the optical module includes a CDR chip and a processor; the CDR chip is used to perform eye diagram scanning on the channels in the communication link to obtain eye diagram data. The processor is used to process the eye diagram data, obtain the eye diagram signal-to-noise ratio (SNR) value based on the processed eye diagram data, and obtain the average value of the eye diagram SNR values ​​after obtaining a preset number of times to obtain the reported SNR value.

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