A method for compensating aging of optical devices

Abstract

The present invention discloses an aging compensation method for optical devices, belonging to the technical field of optical device power compensation. The present invention constructs a statistical prediction model and uses the statistical prediction model to calculate the theoretical compensation amount of the driving current of the optical device to be compensated at time t; constructs a real-time feedback model and uses the real-time feedback model to calculate the feedback compensation amount of the driving current of the optical device to be compensated at time t; establishes a weight function based on the life time inflection point of the optical device; performs weighted fusion of the theoretical compensation amount and the feedback compensation amount through the weight function to obtain the final fused compensation amount of the driving current of the optical device to be compensated at time t; when the ratio of the slope efficiency at time t to the initial slope efficiency is less than 0.95 and the final fused compensation amount is within the compensation boundary condition, the driving current of the optical device to be compensated at time t is compensated based on the final fused compensation amount. The present invention can improve the economic benefits of optical devices while ensuring better use effects of optical devices.

Description

Technical Field

[0001] The present invention relates to the technical field of optical device power compensation, and in particular to an aging compensation method for optical devices. Background Art

[0002] The most important operating unit in optical devices is the semiconductor laser (LD). Its operating characteristics are extremely sensitive to junction temperature. Specifically, as the junction temperature rises, the LD's threshold current increases, efficiency decreases, and thus optical device aging. Specifically, optical device aging failure is often caused by the growth of internal active region defects. As a result, the performance of the optical device slowly decreases with operating time, such as power and voltage drops. Generally speaking, under normal operating conditions, when the operating current or output optical power of an optical device fluctuates by 20%, it is considered to have reached the end of its service life.

[0003] In the related art, there are two main methods for dealing with the failure of optical devices during their working life: one is to directly replace the optical device or optical module itself with a new one; the other is to ensure a good working environment for the optical device or optical module, such as increasing heat dissipation measures, adding semiconductor coolers, etc., by lowering the temperature to reduce the impact of increased junction temperature on the life of the optical device, thereby extending the service life of the optical device and optical module.

[0004] However, the former does not consider the reusability of modules or devices, that is, the failed device or module does not fail while the rest of the hardware is still functional, resulting in poor economic benefits. The latter reduces the junction temperature by increasing heat dissipation and semiconductor coolers. Although this can delay the aging of optical devices, it lacks quantitative detection feedback and compensation methods, resulting in poor actual use of optical devices. Summary of the Invention

[0005] The main purpose of the present invention is to provide an aging compensation method for optical devices, aiming to solve the technical problems of poor economic benefits and poor device performance in related technologies when dealing with the aging problem of optical devices.

[0006] To achieve the above object, the present invention provides an aging compensation method for an optical device, the method comprising the following steps:

[0007] S1, by collecting aging experimental data of the test optical device, building a statistical prediction model, and using the statistical prediction model to calculate the theoretical compensation amount of the driving current of the optical device to be compensated at time t;

[0008] S2, constructing a real-time feedback model based on the step response test results of the test optical device, and using the real-time feedback model to calculate the feedback compensation amount of the drive current of the optical device to be compensated at time t;

[0009] S3, based on the life time inflection point of the optical device, establish a weight function; use the weight function to weightedly fuse the theoretical compensation amount and the feedback compensation amount to obtain the final fused compensation amount of the drive current of the optical device to be compensated at time t;

[0010] S4, when the ratio of the slope efficiency at time t to the initial slope efficiency is less than 0.95 and the final fusion compensation amount is within the compensation boundary condition, the driving current of the optical device to be compensated at time t is compensated based on the final fusion compensation amount.

[0011] The present invention calculates the theoretical compensation amount of the drive current of the optical device to be compensated at time t through a statistical prediction model, and then calculates the feedback compensation amount at time t through a real-time feedback model, thereby using a weight function to perform a weighted fusion of the two to obtain a final fused compensation amount, thereby achieving the effect of using the feedback compensation amount to correct the theoretical compensation amount in real time, thereby avoiding over-compensation of the drive current that accelerates the aging of the optical device and realizing precise and controllable compensation of the drive current. On this basis, by establishing compensation boundary conditions and finely limiting the compensation amount, the negative impact of over-compensation can be further avoided. Therefore, while extending the service life of the optical device, the present invention can perform real-time correction of the compensation amount of the drive current based on real-time feedback, thereby accurately compensating the drive current. It can be seen that the present invention can ensure better use of the optical device while improving economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Schematic diagram of a flow chart of an embodiment of an aging compensation method for an optical device according to the present invention;

[0013] Figure 2 The figure is a detailed flow chart of an embodiment of the aging compensation method for optical devices of the present invention.

[0014] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0015] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0016] The inventive concept of the present application is further described below with reference to some specific embodiments and implementation methods.

[0017] The embodiment of the present invention provides an aging compensation method for an optical device, referring to Figure 1 , Figure 1 The figure is a flow chart of a first embodiment of an aging compensation method for an optical device according to the present invention.

[0018] In this embodiment, the optical device aging compensation method includes the following steps:

[0019] Step S1: by collecting aging test data of the test optical device, constructing a statistical prediction model, and using the statistical prediction model to calculate the theoretical compensation amount of the driving current of the optical device to be compensated at time t.

[0020] It's worth noting that in this embodiment, the experimental optical device is a new optical device used for aging testing, while the optical device to be compensated is an optical device after normal use. Aging testing involves subjecting the test optical device to a specific aging environment (such as a temperature of 85°C, a humidity of 85%, or high current) to accelerate aging and measure key performance parameters of the test optical device (including but not limited to actual output optical power, actual drive current, and actual threshold current).

[0021] like Figure 2 As shown, step S1 specifically includes the following steps:

[0022] Step S11: Based on the aging test data of multiple test optical components, a statistical prediction model is constructed through least square fitting calculation.

[0023] The step S11 specifically includes:

[0024] Collect the actual output power P of multiple test optical devices at different aging time points out and the actual driving current I, as aging experiment data.

[0025] Based on the aging test data, the threshold current I at the corresponding time point is calculated by fitting the relationship between the output optical power and the driving current. th (t); The relationship between output optical power and driving current:

[0026] ;

[0027] Among them, P out (t) represents the output optical power at time t; I(t) represents the driving current at time t; It represents the slope efficiency at time t, which represents the optical power gain corresponding to the unit current increment.

[0028] Based on the threshold current I of the experimental optical device th (t) and the corresponding time point, the aging rate coefficient is determined by fitting the relationship between threshold current and time and time index n, thereby obtaining a statistical prediction model.

[0029] The Arrhenius degradation model is used to fit the aging rate of optical devices, and the relationship between threshold current and time is abstracted:

[0030] ;

[0031] Among them, I th0 represents the initial threshold current; Indicates the aging rate coefficient; I th (t) represents the threshold current at time t; n represents the time index (0.5≤n≤1).

[0032] Step S12: Collect the initial threshold current I of the optical device to be compensated th0,p , and bring it into the statistical prediction model to obtain the predicted threshold current I of the optical device to be compensated at time t th,p (t).

[0033] Step S13: Collect the output optical power P of the optical device to be compensated at time t out (t) and driving current I(t), based on the output optical power P at time t out (t), driving current I(t) and predicted threshold current I th,p (t), the slope efficiency at time t is calculated by the relationship between the output optical power and the driving current :

[0034] .

[0035] It is worth mentioning that during the operation of optical devices, as the operating time increases, the optical devices will gradually age. Under the same driving current, the actual output optical power of the optical device will gradually become less than the designed optical power (that is, the target optical power).

[0036] Step S14: Based on the target optical power P target , initial threshold current I th0,p , output optical power P at time t out (t), predicted threshold current I at time t th,p (t) and the slope efficiency at time t , calculate the theoretical compensation amount at time t:

[0037] ;

[0038] in, Indicates the theoretical compensation amount at time t; P target Indicates the target optical power.

[0039] In the entire step S1, by performing aging tests on multiple test optical devices and establishing a statistical prediction model based on the aging test data, the threshold current of the optical device to be compensated at time t is more accurately predicted, thereby accurately calculating the theoretical compensation amount of the driving current of the optical device to be compensated at time t, laying the foundation for the accurate calculation of the final fusion compensation amount.

[0040] Step S2: constructing a real-time feedback model based on the step response test results of the optical device, and using the real-time feedback model to calculate the feedback compensation amount of the driving current of the optical device to be compensated at time t.

[0041] The step S2 specifically includes the following steps:

[0042] Step S21: performing a step response experiment on the experimental optical device under different driving currents, determining and constructing a real-time feedback model based on the proportional gain and the integral gain.

[0043] It is worth mentioning that, in this embodiment, once the optical device starts to work, the optical device begins to age gradually, and the working time of the optical device is also the aging time.

[0044] The step S21 specifically includes the following steps:

[0045] Firstly, four aging time nodes are set, and step response experiments of the four aging time nodes are carried out under different driving currents to obtain four corresponding sets of critical gains and critical periods.

[0046] The four aging time nodes are 0h, 2000h, 5000h and 8000h.

[0047] Then, based on the four sets of critical gains and critical periods corresponding to the four aging time nodes, four sets of proportional gains and integral gains are calculated using the Ziegler-Nichols empirical formula.

[0048] Specifically, the step response experiment of the experimental optical device with an aging time of 0h under different driving currents is introduced as an example. Set the driving current I to 40mA and the target optical power P target is 2.5mW, initial K p =0.1 (to ensure a smooth adjustment process), K i =0 (at this time, only proportional control is used for adjustment); collect output optical power P out (t) and calculate the optical power error ,according to Adjust the drive current to (The closed-loop regulation of optical power is achieved through proportional control, so that the actual output optical power gradually approaches the target optical power.) Then, the target optical power P target Increase to 2.8mW (by artificially introducing a step input to force the system to exhibit critical oscillation characteristics during the adjustment process), and slowly increase K in steps of 0.1 p Observe the optical power curve on the oscilloscope; when there are at least 5 cycles of continuous equal-amplitude oscillation, record the K at this time p , which is the critical gain K cr , read the time from the peak to the trough, which is the critical period Tcr Finally, a set of proportional gains is calculated based on the Ziegler-Nichols empirical formula and integral gain This set of proportional gain and integral gain is used as the proportional gain and integral gain corresponding to 0-2000h. Similarly, a set of proportional gain and integral gain corresponding to 2000-5000h, a set of proportional gain and integral gain corresponding to 5000-8000h, and a set of proportional gain and integral gain corresponding to more than 8000h can be obtained.

[0049] Finally, a real-time feedback model is constructed based on four sets of proportional gains and integral gains.

[0050] For example, if the aging time of the optical component to be compensated is less than 2000 h, a set of proportional gains and integral gains corresponding to the interval of 0-2000 h is used to construct a real-time feedback model.

[0051] Specifically, based on the target optical power P of the compensation optical device target And the output optical power p at time t out (t), calculate the optical power error:

[0052] ;

[0053] in, Represents the optical power error at time t.

[0054] Optical power error Take the derivative and obtain the relationship 1:

[0055] ;

[0056] Substituting the relationship between output optical power and driving current into equation 1, we obtain equation 2:

[0057] ;

[0058] Since the slope efficiency and threshold current change very slowly during the control cycle, they can be approximately regarded as constants. Therefore, the error equation is simplified to obtain:

[0059] .

[0060] The error equation shows that when the optical power error approaches 0, the drive current approaches a constant, which means that the optical power error and the drive current meet the proportional-integral control condition. Therefore, based on the proportional gain, integral gain, and proportional-integral control expression corresponding to the aging time, a proportional-integral controller for the drive current is constructed:

[0061] ;

[0062] Based on the optical power error and the proportional-integral controller, a real-time feedback model is obtained:

[0063] ;

[0064] in, Represents the feedback compensation amount at time t.

[0065] Step S22: inputting the target optical power of the optical device to be compensated and the output optical power at time t into the real-time feedback model to obtain the feedback compensation amount at time t.

[0066] In the entire step S2, a step response test is performed on multiple optical devices, and a real-time feedback model is established based on the test results. At the same time, combined with the aging test of the optical devices, the proportional gain and the integral gain are set in multiple aging time intervals of the optical devices, so that the feedback compensation amount of the optical device to be compensated at time t can be calculated more accurately, thereby accurately correcting the theoretical compensation amount obtained in step S1, avoiding overcompensation, and greatly improving the accuracy of the drive current compensation.

[0067] Step S3: Based on the life time inflection point of the optical device, a weight function is established; the theoretical compensation amount and the feedback compensation amount are weightedly integrated through the weight function to obtain the final integrated compensation amount of the driving current of the optical device to be compensated at time t.

[0068] The step S3 specifically includes the following steps:

[0069] Step S31: establishing a weighting function based on the life time inflection point of the optical component.

[0070] The step S31 specifically includes the following steps:

[0071] Set the initial value of the life time inflection point, the life time inflection point includes the first time inflection point t0 and the second time inflection point t1. Establish a weight function based on the initial values ​​of the first time inflection point t0 and the second time inflection point t1 :

[0072] .

[0073] According to analysis of a large amount of experimental data, the initial value of the first time inflection point t0 is preferably 2000 h, and the initial value of the second time inflection point t1 is preferably 8000 h.

[0074] Collect the actual threshold current I of the optical device to be compensated at time t th,r , and calculate the prediction error of the predicted threshold current at time t compared to the actual threshold current:

[0075] ;

[0076] in, represents the prediction error at time t; I th,r Represents the actual threshold current at time t.

[0077] As time changes, the actual threshold current and the predicted threshold current will also change, so the prediction error will also change. Record the critical time point when the prediction error reaches 10%, and update the first time inflection point to the critical time point when the prediction error is 10%; record the critical time point when the prediction error reaches 20%, and update the second time inflection point to the critical time point when the prediction error is 20%.

[0078] Step S32: Establish a fusion adjustment function based on the weight function:

[0079] ;

[0080] in, Represents the final fusion compensation at time t.

[0081] Step S33: Perform weighted fusion of the theoretical compensation amount and the feedback compensation amount through the fusion adjustment function to obtain the final fusion compensation amount at time t.

[0082] In the entire step S3, a segmented weight function is established according to different aging time intervals, and the theoretical compensation amount and the feedback compensation amount are weightedly fused. The theoretical compensation amount can be accurately corrected according to the different aging degrees of the optical device to be compensated in different time periods, thereby obtaining a final fused compensation amount that better matches the aging degree of the optical device to be compensated at time t, thereby improving the compensation accuracy of the driving current of the optical device to be compensated.

[0083] Step S4: When the ratio of the slope efficiency at time t to the initial slope efficiency is less than 0.95 and the final fusion compensation amount is within the compensation boundary condition, the driving current of the optical device to be compensated at time t is compensated based on the final fusion compensation amount.

[0084] The step S4 specifically includes the following steps:

[0085] Step S41: establishing compensation boundary conditions based on the maximum allowable junction temperature of the optical device.

[0086] Based on the definition of thermodynamics, the thermal resistance of optical devices is defined as:

[0087] , ;

[0088] Among them, R th Represents the thermal resistance of the optical device; P h Indicates heating power; Indicates temperature rise; P outIndicates the actual output power; V indicates the device voltage; I indicates the drive current.

[0089] A fixed driving current is applied to the test optical device, and the temperature rise curve is recorded. At the same time, the actual output power and device voltage are collected in real time, and the thermal resistance of the optical device is obtained by fitting.

[0090] Compared with the aging cycle of the test optical device, the change in drive current is extremely small. Therefore, the change in slope efficiency, threshold current, and device voltage caused by the change in drive current is ignored. Based on the law of conservation of energy, the heat power increment formula is constructed:

[0091] ;

[0092] Where V(t) represents the device voltage at time t; Represents the output power increment after compensation at time t.

[0093] Based on the heat power increment formula, the junction temperature after compensation at time t is obtained:

[0094] ;

[0095] Among them, T j (t) represents the measured junction temperature before compensation at time t; Represents the junction temperature after compensation at time t.

[0096] Based on compensated junction temperature and the maximum allowable junction temperature T M , establish compensation boundary conditions:

[0097] First, set the maximum allowable junction temperature T M ,constraint , we get the compensation boundary conditions:

[0098] .

[0099] Step S42: Calculate the ratio of the slope efficiency of the optical device to be compensated at time t to the initial slope efficiency. If the ratio is less than 0.95, determine whether the final fusion compensation amount meets the compensation boundary condition; otherwise, directly output the driving current at time t.

[0100] Step S43: If the final fusion compensation amount meets the compensation boundary condition, the driving current of the optical device to be compensated at time t is compensated based on the final fusion compensation amount, and the compensated driving current is output; otherwise, the driving current at time t is directly output.

[0101] In the entire step S4, compensation boundary conditions are established according to the maximum allowable junction temperature of the optical device, and the final fusion compensation amount is limited. This can avoid overcompensation causing the junction temperature of the optical device to be compensated to exceed the maximum allowable junction temperature, thereby accelerating the aging of the optical device to be compensated and further improving the compensation accuracy of the optical device drive current.

[0102] In this embodiment, a statistical prediction model is used to calculate the theoretical compensation amount of the drive current of the optical device to be compensated at time t. The feedback compensation amount at time t is then calculated using a real-time feedback model. A weighted fusion of the two is then performed using a weight function to obtain a final fused compensation amount. This achieves the effect of using the feedback compensation amount to correct the theoretical compensation amount in real time, thereby preventing overcompensation of the drive current from accelerating aging of the optical device and achieving precise and controllable compensation of the drive current. Furthermore, by establishing compensation boundary conditions and finely limiting the compensation amount, the negative effects of overcompensation can be further avoided. Therefore, while extending the service life of the optical device, the present invention can make real-time corrections to the drive current compensation amount based on real-time feedback, thereby accurately compensating the drive current. Thus, the present invention can ensure optimal performance of the optical device while improving economic efficiency.

[0103] The serial numbers of the above embodiments of the present invention are for description only and do not represent the advantages or disadvantages of the embodiments.

[0104] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for compensating for aging of an optical device, characterized in that: The method comprises the following steps: S1, by collecting aging experimental data of the test optical device, building a statistical prediction model, and using the statistical prediction model to calculate the theoretical compensation amount of the driving current of the optical device to be compensated at time t; Said S1 specifically includes: S11, based on the aging test data of multiple experimental optical devices, a statistical prediction model is constructed by least squares fitting calculation; S12, collecting the initial threshold current I of the optical device to be compensated th0,p , substitute into the statistical prediction model to obtain the predicted threshold current I of the optical device to be compensated at time t th,p (t); S13, collecting the output optical power P of the optical device to be compensated at time t out (t) and driving current I(t), based on the output optical power P at time t out (t), driving current I(t) and predicted threshold current I th,p (t), the slope efficiency at time t is calculated by the relationship between the output optical power and the driving current : ； S14, based on the target optical power P target , initial threshold current I th0,p , output optical power P at time t out (t), predicted threshold current I at time t th,p (t) and the slope efficiency at time t , calculate the theoretical compensation amount at time t: ； in, Indicates the theoretical compensation amount at time t; P target Indicates the target optical power; S2, constructing a real-time feedback model based on the step response test results of the test optical device, and using the real-time feedback model to calculate the feedback compensation amount of the drive current of the optical device to be compensated at time t; S3, based on the life time inflection point of the optical device, establish a weight function; use the weight function to weightedly fuse the theoretical compensation amount and the feedback compensation amount to obtain the final fused compensation amount of the drive current of the optical device to be compensated at time t; The S3 specifically includes: S31, establishing a weight function based on the life time inflection point of the optical device; Set the initial value of the life time inflection point, the life time inflection point includes the first time inflection point t0 and the second time inflection point t1; establish a weight function based on the initial value of the first time inflection point t0 and the second time inflection point t1 : ； Collect the actual threshold current I of the optical device to be compensated at time t th,r , and calculate the prediction error of the predicted threshold current at time t compared to the actual threshold current: ； in, represents the prediction error at time t; I th,r represents the actual threshold current at time t; Record the critical time point when the prediction error reaches 10%, and update the first time inflection point to the critical time point when the prediction error is 10%; record the critical time point when the prediction error reaches 20%, and update the second time inflection point to the critical time point when the prediction error is 20%; S32, establishing a fusion adjustment function based on the weight function; ； in, represents the final fusion compensation at time t; S33, performing weighted fusion of the theoretical compensation amount and the feedback compensation amount through a fusion adjustment function to obtain a final fusion compensation amount at time t; S4, when the ratio of the slope efficiency at time t to the initial slope efficiency is less than 0.95 and the final fusion compensation amount is within the compensation boundary condition, the driving current of the optical device to be compensated at time t is compensated based on the final fusion compensation amount.

2. The optical device aging compensation method according to claim 1, wherein: The S11 specifically includes: S11-1, collect the actual output power P of multiple test optical devices at different aging time points out and the actual driving current I, as aging experiment data; S11-2, based on the aging test data, the threshold current I at the corresponding time point is calculated by fitting the relationship between the output optical power and the driving current. th (t); The relationship between output optical power and driving current: ； Among them, P out (t) represents the output optical power at time t; I(t) represents the driving current at time t; It represents the slope efficiency at time t, which represents the optical power gain corresponding to the unit current increment; S11-3, based on the threshold current I of the experimental optical device th (t) and the corresponding time point, the aging rate coefficient is determined by fitting the relationship between threshold current and time and time index n, thereby obtaining a statistical prediction model; ； Among them, I th0 represents the initial threshold current; Indicates the aging rate coefficient; I th (t) represents the threshold current at time t; n represents the time index.

3. The optical device aging compensation method according to claim 1, wherein: The S2 specifically includes: S21, conduct step response experiments on the experimental optical device at different driving currents, determine and construct a real-time feedback model based on the proportional gain and integral gain; S22 , inputting the target optical power of the optical device to be compensated and the output optical power at time t into a real-time feedback model to obtain a feedback compensation amount at time t.

4. The optical device aging compensation method according to claim 3, wherein: The S21 specifically includes: S21-1, setting four aging time nodes, performing step response experiments at the four aging time nodes under different driving currents, and obtaining four corresponding sets of critical gains and critical periods; S21-2, based on the four sets of critical gains and critical periods corresponding to the four aging time nodes, four sets of proportional gains and integral gains are calculated using the Ziegler-Nichols empirical formula; S21-3, based on four sets of proportional gains and integral gains, a real-time feedback model is constructed.

5. The optical device aging compensation method according to claim 1, wherein: The S4 specifically includes: S41, establishing compensation boundary conditions based on the maximum allowable junction temperature of the optical device; S42, calculating the ratio of the slope efficiency of the optical device to be compensated at time t to the initial slope efficiency. If the ratio is less than 0.95, determining whether the final fusion compensation amount meets the compensation boundary condition; otherwise, directly outputting the driving current at time t; S43, if the final fusion compensation amount meets the compensation boundary condition, the driving current of the optical device to be compensated at time t is compensated based on the final fusion compensation amount, and the compensated driving current is output; otherwise, the driving current at time t is directly output.

6. The optical device aging compensation method according to claim 5, wherein: The S41 specifically includes: S41-1, based on thermodynamics, define the thermal resistance of optical devices; S41-2, ignoring the slope efficiency change, threshold current change, and device voltage change of the test optical device, construct the heat generation power increment formula based on the law of conservation of energy; S41-3, based on the heat power increment formula, obtain the junction temperature after compensation at time t; S41-4, establishing compensation boundary conditions based on the compensated junction temperature and the maximum allowable junction temperature.

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