Method and system for evaluating heat dissipation performance of VCSEL (Vertical Cavity Surface Emitting Laser)

Abstract

The invention relates to the technical field of semiconductor lasers, in particular to a heat dissipation performance evaluation method and system for a VCSEL (vertical cavity surface emitting laser), and the method comprises the steps: obtaining the operation data of the VCSEL, and the optimal operation data; based on the operation data of the vertical cavity surface emitting laser and the optimal operation data, the aperture heat accumulation degree is determined, and the aperture heat accumulation degree is used for representing the operation data of the vertical cavity surface emitting laser and the difference between the optimal operation data; and evaluating the heat dissipation performance of the vertical cavity surface emitting laser based on the aperture heat accumulation degree. According to the invention, the heat dissipation performance of the vertical cavity surface emitting laser can be comprehensively and accurately evaluated.

Description

Technical Field

[0001] This invention relates to the field of semiconductor laser technology, and more specifically to a method and system for evaluating the heat dissipation performance of a VCSEL laser. Background Technology

[0002] In related technologies, when evaluating the heat dissipation performance of a vertical-cavity surface-emitting laser (VCSEL), the temperature at a certain location of the VCSEL can be measured. If the temperature at that location is too high, it is determined that the heat dissipation performance of the VCSEL is poor.

[0003] However, the temperature of the entire laser is not uniformly distributed, and it is inaccurate to evaluate the heat dissipation performance of the laser based on the temperature at only one location. Summary of the Invention

[0004] To address the technical problem of inaccurate heat dissipation performance evaluation of lasers based on temperature at a single location, the present invention aims to provide a method and system for evaluating the heat dissipation performance of VCSEL lasers. The specific technical solution adopted is as follows: This application provides a method for evaluating the heat dissipation performance of a VCSEL laser, the method comprising: The system acquires operational data and optimal operational data for the vertical-cavity surface-emitting laser (VCSEL), which represents the laser with the best heat dissipation performance. This optimal operational data includes temperatures at multiple locations during operation and output data, including output power and wavelength. Based on the operational data and optimal operational data, the system determines the aperture heat accumulation level, which characterizes the difference between the operational data and the optimal operational data. Finally, based on this aperture heat accumulation level, the system evaluates the heat dissipation performance of the VCSEL.

[0005] In some embodiments, determining the aperture heat accumulation degree based on the operating data of the vertical-cavity surface-emitting laser and the optimal operating data specifically includes: determining a first deviation index based on the operating data of the vertical-cavity surface-emitting laser and determining an optimal deviation index based on the optimal operating data, wherein the first deviation index is the deviation index of the vertical-cavity surface-emitting laser, and a deviation index is used to characterize the degree of temperature increase and the degree of weakening of the output data at the plurality of locations during the operating period; and determining the aperture heat accumulation degree based on the first deviation index and the optimal deviation index.

[0006] In some embodiments, determining the first deviation index based on the operating data of the vertical-cavity surface-emitting laser specifically includes: determining the degree of heat accumulation centering at multiple target locations within the operating period based on the temperatures at multiple locations within the operating period, wherein the degree of heat accumulation centering at a target location is used to characterize the temperature level within a target region, and a target region includes a target location and adjacent locations of the target location, wherein the temperature of the target location is higher than the temperature of the adjacent locations of the target location; determining the degree of light output influence at each target location based on the degree of heat accumulation centering at multiple target locations within the operating period and the output data within the operating period, wherein the degree of light output influence at a target location is used to characterize the effect of temperature changes at the target location on the output data; and determining the first deviation index based on the degree of light output influence at each target location and the degree of heat accumulation centering at each target location.

[0007] In some embodiments, the degree of light output impact of the first target location is determined based on the degree of heat accumulation centering at the first target location during the operating period and the output data during the operating period. Specifically, this includes: determining the degree of heat accumulation impact at each moment based on the degree of power attenuation and the degree of wavelength redshift at each moment, wherein the power attenuation value at each moment is the power difference between the current moment and the previous moment, and the wavelength redshift value at each moment is the ratio of the wavelength at each moment to the reference wavelength, and the degree of heat accumulation impact at each moment is positively correlated with both the degree of power attenuation and the degree of wavelength redshift at each moment; determining the degree of heat accumulation change at the first target location at multiple moments based on the degree of heat accumulation centering at the first target location during the operating period, wherein the degree of heat accumulation change is the difference between the degree of heat accumulation centering at each moment and the degree of heat accumulation centering at the previous moment, and the first target location is one of the multiple target locations; and determining the degree of light output impact of the first target location based on the degree of heat accumulation impact at each moment and the degree of heat accumulation change at multiple moments.

[0008] In some embodiments, determining the light output impact level of the first target location based on the degree of heat accumulation impact at each moment and the degree of heat accumulation change at multiple moments specifically includes: determining a first abrupt change moment, which is the moment when the degree of heat accumulation change at the first target location is the largest; determining the heat accumulation impact growth index of the first abrupt change moment by the difference between the degree of heat accumulation impact at the first abrupt change moment and the degree of heat accumulation impact at the previous moment, which is used to characterize the degree of impact of the temperature abrupt change at the abrupt change moment on the output data; and determining the light output impact level of the first target location based on the heat accumulation impact growth index of the first abrupt change moment and the degree of heat accumulation change at the first abrupt change moment.

[0009] In some embodiments, determining the degree of aperture heat accumulation based on the first deviation index and the optimal deviation index specifically includes: obtaining the aperture size of the oxide hole of the vertical cavity surface-emitting laser and the aperture size of the oxide hole corresponding to the optimal operating data; determining the degree of aperture heat accumulation based on the difference between the aperture size of the oxide hole of the vertical cavity surface-emitting laser and the aperture size of the oxide hole corresponding to the optimal operating data, and the difference between the first deviation index and the optimal deviation index.

[0010] In some embodiments, obtaining the optimal operating data specifically includes: constructing a simulation model based on the degree of influence of light output at each position of the vertical cavity surface-emitting laser; obtaining operating data corresponding to multiple oxide hole aperture sizes based on the simulation model; determining the deviation index of the operating data corresponding to each oxide hole aperture size; and determining the operating data with the smallest deviation index as the optimal operating data.

[0011] In some embodiments, the above-mentioned evaluation of the heat dissipation performance of the vertical cavity surface-emitting laser based on the degree of heat accumulation of the aperture specifically includes: determining the heat dissipation score of the vertical cavity surface-emitting laser based on the confidence level of the oxide aperture and the degree of heat accumulation of the aperture, wherein the confidence level of the oxide aperture is used to characterize the degree of influence of the size of the oxide aperture on the heat dissipation performance; and determining that the heat dissipation performance of the vertical cavity surface-emitting laser is poor when the heat dissipation score is greater than the heat dissipation score threshold.

[0012] In some embodiments, determining the confidence level of the oxide pore specifically includes: determining the confidence level of the oxide pore based on the ratio between the highest temperature difference at each location and the maximum value of the highest temperature differences at the plurality of locations.

[0013] The present invention also proposes a heat dissipation performance evaluation system for a VCSEL laser, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements any of the steps of the heat dissipation performance evaluation method for a VCSEL laser.

[0014] The present invention has the following beneficial effects: In this embodiment, the operating data and optimal operating data of the vertical-cavity surface-emitting laser (VCSEL) can be obtained. Based on the operating data and optimal operating data, the aperture heat accumulation degree is determined, and the heat dissipation performance of the VCSEL is evaluated based on the aperture heat accumulation degree. Since the operating data includes temperature and output data at multiple locations, the heat dissipation performance of the VCSEL can be more comprehensively reflected based on the operating data. Furthermore, since the optimal operating data represents the operating data of the laser with the best heat dissipation performance, the difference between the operating data and the optimal operating data can be accurately assessed based on the operating data and the optimal operating data. Evaluating the heat dissipation performance of the VCSEL based on this difference allows for an accurate and comprehensive assessment of the difference between the heat dissipation performance of the VCSEL and the optimal heat dissipation performance. Attached Figure Description

[0015] To more clearly illustrate the technical solutions and advantages 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.

[0016] Figure 1 A flowchart illustrating a method for evaluating the heat dissipation performance of a VCSEL laser, as provided in one embodiment of the present invention; Figure 2 A flowchart illustrating another method for evaluating the heat dissipation performance of a VCSEL laser, as provided in an embodiment of the present invention; Figure 3 A schematic diagram of a method for evaluating the heat dissipation performance of a VCSEL laser according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a VCSEL laser provided in one embodiment of the present invention; Figure 5 This is a front view of a VCSEL laser provided in one embodiment of the present invention; Figure 6 This is a schematic diagram of a distributed temperature sensor array structure for a VCSEL laser provided in one embodiment of the present invention; Among them, 11 is the substrate layer; 12 is the lower DBR layer; 13 is the active region; 14 is the upper DBR layer; 15 is the oxide confinement layer with oxide pores; 16 is the positive electrode; 17 is the negative electrode; and 18 is the distributed temperature sensor. Detailed Implementation

[0017] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a VCSEL laser heat dissipation performance evaluation method and system proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0019] A vertical cavity surface emitting laser (VCSEL) is a semiconductor laser that emits laser light in a direction perpendicular to the surface of a chip. It consists of a substrate, oxide holes, two distributed bragg reflectors (DBRs) sandwiching a multi-quantum-well active region. VCSELs offer advantages such as perpendicular emission direction, low threshold current, small beam divergence angle, and ease of integration into two-dimensional arrays, making them widely used in optical communication, 3D sensing, lidar, and high-performance sensing. Compared to edge-emitting lasers, VCSELs are better suited for high-density integration and low-power operating environments.

[0020] As a concrete example, a schematic diagram of a VCSEL laser is shown below. Figure 4 As shown, its main view is as follows Figure 5 As shown. During the operation of the VCSEL laser: Current is injected from the positive electrode 16 and flows downward through the upper DBR layer 14; the current is laterally constrained by the oxide confinement layer 15 with oxide holes, allowing the current to enter the active region 13 only through the central region; the oxide holes, due to their insulating properties, prevent the edge current from spreading, thereby achieving current convergence and mode confinement, ensuring that the optical mode and the current path are highly coincident.

[0021] Within the active region 13, electrons and holes recombine to generate stimulated emission photons. The photons reflect back and forth between the lower DBR layer 12 and the upper DBR layer 14 to form an optical resonant cavity. Each round trip enhances the light field of a specific wavelength. When the gain reaches a threshold, the device begins to emit light through lasing. The upper DBR layer 14 has a slightly lower reflectivity, which allows some light energy to leak out from the top of the device, forming visible laser output.

[0022] The laser beam is emitted vertically from the openings in the upper DBR layer 14 and the positive electrode 16, forming a highly coherent, circularly symmetrical output beam. As the driving current increases, the output power rises, but so does the heat accumulation. Heat is generated by non-radiative recombination of charge carriers, ohmic loss, and light absorption, mainly concentrated in the active region 13 and around the oxide holes 15. The generated heat is conducted vertically to the substrate layer 11 and released through the negative electrode 17 and the external heat dissipation structure.

[0023] like Figure 6 As shown, a distributed temperature sensor array 18 is integrated on the device substrate to monitor the thermal accumulation effect caused by the large difference in thermal conductivity between the DBR layer and the active region.

[0024] VCSELs are prone to localized heat buildup under high-power, high-density integration and continuous operation conditions, especially due to the complex thermal resistance paths between oxide vias, the active region, and the upper and lower diode-received circuits (DBRs). This leads to rapid device temperature rise, decreased optical output power, wavelength drift, and even thermal runaway. Therefore, to ensure the stability of the optoelectronic performance and the lifespan of the device, as well as its reliability in critical applications such as high-speed communication and lidar, it is necessary to evaluate the heat dissipation performance of VCSELs.

[0025] The oxide orifices in VCSELs are responsible for limiting current and light modes, but they also limit the heat diffusion path. The size of the oxide orifice diameter affects the heat dissipation performance of VCSELs. In the existing technology, the heat dissipation performance of VCSELs is usually evaluated by single-point temperature measurement or static simulation. This method cannot dynamically reflect the relationship between the oxide orifice diameter and the temperature change of local hot spots, and therefore cannot determine whether poor heat dissipation performance is caused by poor oxide orifice size. As a result, the heat dissipation performance evaluation of VCSELs is inaccurate.

[0026] Based on this, a method and system for evaluating the heat dissipation performance of VCSEL lasers are proposed. Since the operating data includes temperature and output data at multiple locations, the heat dissipation performance of the VCSEL can be more comprehensively reflected based on the operating data. Furthermore, since the optimal operating data is the operating data of the laser with the best heat dissipation performance, the difference between the operating data and the optimal operating data of the VCSEL can be accurately evaluated based on the operating data and the optimal operating data. The heat dissipation performance of the VCSEL can be evaluated based on this difference, and the difference between the heat dissipation performance of the VCSEL and the optimal heat dissipation performance can be accurately evaluated.

[0027] The specific scheme of the heat dissipation performance evaluation method for VCSEL lasers provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0028] Please see Figure 1The diagram illustrates a flowchart of a method for evaluating the heat dissipation performance of a VCSEL laser according to an embodiment of the present invention.

[0029] like Figure 1 As shown, the method includes S101-S103.

[0030] S101. Obtain the operating data and optimal operating data of the vertical cavity surface-emitting laser.

[0031] Among them, the optimal operating data refers to the operating data of the laser with the best heat dissipation performance.

[0032] It should be understood that the operating data of a vertical-cavity surface-emitting laser (VCSEL) is the data generated after the VCSEL begins operation. This operating data includes the temperature at multiple locations during the operating period and the output data during that period, which includes the output power and wavelength.

[0033] Optionally, the output data may also include output voltage, output current, etc.

[0034] It should be understood that the operation of this vertical-cavity surface-emitting laser will cause the temperature to rise. When heat accumulates in certain locations, it will affect the light output of the vertical-cavity surface-emitting laser, namely the output power and wavelength. Therefore, based on the above operating data, the heat dissipation performance of the vertical-cavity surface-emitting laser can be measured more accurately.

[0035] Understandably, the temperatures at multiple locations during this operating period can be used to monitor the thermal buildup effect between the DBR layer and the active region due to the large difference in thermal conductivity between the materials.

[0036] It should be understood that the vertical cavity surface-emitting laser contains oxide holes, and the heat dissipation performance varies with different oxide hole sizes. The optimal operating data is the operating data corresponding to the optimal oxide hole diameter size.

[0037] In one alternative implementation, the operating data can be acquired at a certain frequency during the operation of the vertical cavity surface-emitting laser.

[0038] Optionally, a distributed temperature sensor array can be integrated into the substrate of the vertical cavity surface-emitting laser, with a sampling frequency of 10 Hz, to collect the temperature at multiple locations at multiple times.

[0039] It should be understood that these multiple locations are the locations where temperature data is collected by the temperature sensor.

[0040] Optionally, the real-time output power of the vertical cavity surface-emitting laser can be measured using an integrating sphere and a photodetector at a sampling frequency of 100 Hz.

[0041] Optionally, the wavelength of the laser center of the vertical cavity surface-emitting laser can be acquired using a miniature spectrometer at a frequency of 10 Hz.

[0042] Optionally, an analog-to-digital converter (ADC) can be built into the power supply of the vertical cavity surface-emitting laser to acquire real-time output current and voltage at a sampling frequency of 100Hz.

[0043] S102. Determine the aperture heat accumulation level based on the operating data and optimal operating data of the vertical cavity surface-emitting laser.

[0044] The degree of heat accumulation at this aperture is used to characterize the operating data of the vertical cavity surface-emitting laser, as well as the difference between the optimal operating data and the data.

[0045] Based on the description of the above embodiments, the differences mainly include differences in temperature changes, differences in output power changes, and differences in wavelength changes.

[0046] It should be understood that when the temperature change, output power change, and wavelength change are small, it indicates that the vertical cavity surface-emitting laser has good heat dissipation performance. Therefore, the optimal operating data corresponds to small temperature change, small output power change, and small wavelength change.

[0047] S103. The heat dissipation performance of the vertical cavity surface-emitting laser is evaluated based on the degree of heat accumulation in the aperture.

[0048] It should be understood that the smaller the heat accumulation of this aperture, the smaller the difference between the heat dissipation performance of this vertical cavity surface-emitting laser and the heat dissipation performance of the laser with the optimal oxide aperture size, indicating that the heat dissipation performance of this vertical cavity surface-emitting laser is better.

[0049] In one alternative implementation, an aperture heat accumulation threshold can be set. When the aperture heat accumulation is less than the aperture heat accumulation threshold, the heat dissipation performance of the vertical cavity surface-emitting laser is determined to be good. When the aperture heat accumulation is greater than or equal to the aperture heat accumulation threshold, the heat dissipation performance of the vertical cavity surface-emitting laser is determined to be poor.

[0050] In this embodiment, since the operating data includes temperature and output data at multiple locations, the heat dissipation performance of the vertical-cavity surface-emitting laser (VCSEL) can be more comprehensively reflected based on the operating data. Furthermore, since the optimal operating data is the operating data of the laser with the best heat dissipation performance, the difference between the operating data and the optimal operating data of the VCSEL can be accurately assessed based on the operating data and the optimal operating data. The heat dissipation performance of the VCSEL can be evaluated based on this difference, and the difference between the heat dissipation performance of the VCSEL and the optimal heat dissipation performance can be accurately assessed.

[0051] In one implementation of this application embodiment, the aperture heat accumulation degree is determined based on the operating data of the vertical-cavity surface-emitting laser and the optimal operating data, such as... Figure 2 As shown, this can be achieved through S201-S202.

[0052] S201. Determine the first deviation index based on the operating data of the vertical cavity surface-emitting laser, and determine the optimal deviation index based on the optimal operating data.

[0053] The first deviation index is the deviation index of the vertical cavity surface-emitting laser. A deviation index is used to characterize the degree of temperature rise at the multiple locations during the operation period and the degree of attenuation of the output data.

[0054] Specifically, the degree of heat accumulation center at multiple target locations within the operating period can be determined first based on the temperature at these multiple locations within the operating period. Then, based on the degree of heat accumulation center at these multiple target locations within the operating period and the output data within the operating period, the degree of light output influence at each target location can be determined. Finally, based on the degree of light output influence at each target location and the degree of heat accumulation center at each target location, the first deviation index can be determined.

[0055] Among them, the heat accumulation center degree of a target location is used to characterize the temperature level within a target area. A target area includes a target location and its adjacent locations, and the temperature of the target location is higher than the temperature of its adjacent locations. The light output influence degree of the target location is used to characterize the impact of temperature changes at the target location on the output data.

[0056] It should be understood that the target location is a hotspot, and the adjacent area of ​​a target location includes the target location and its adjacent locations.

[0057] In one alternative implementation, the temperature of each temperature sensor at any given moment is first obtained from the distributed temperature sensor array. The location of the target sensor whose temperature value is greater than that of all its neighboring sensors is determined as the target location. The average temperature of any target sensor at that moment and the temperature of its neighboring sensors is recorded as the heat accumulation center degree of the target location at that moment.

[0058] Optionally, the obtained multiple heat accumulation center degrees can be normalized.

[0059] Alternatively, among the locations of target sensors where the temperature value is greater than that of all its adjacent sensors, the temperature of the sensor with a temperature greater than the first temperature threshold can be selected as the target location, and the hot spot with a high degree of heat accumulation can be selected.

[0060] It should be understood that heat accumulation significantly affects the optical output of a vertical-cavity surface-emitting laser (VCSEL). Increased active region temperature leads to decreased carrier recombination efficiency and increased nonradiative recombination, resulting in reduced slope efficiency. Temperature rise also causes a gain spectrum redshift and resonant cavity drift mismatch, leading to a decrease in optical output power. Furthermore, increased junction temperature can induce laser wavelength drift, unstable mode transitions, and even thermal lensing effects, ultimately manifesting as reduced output power and a redshift. Therefore, the extent of the impact of heat accumulation on the optical output of a VCSEL can be determined based on changes in output power and wavelength.

[0061] In this embodiment of the application, the degree of influence of each target position on the light output of the vertical cavity surface-emitting laser can be determined sequentially.

[0062] In one implementation of this application, the determination of the light output impact of the first target location based on the degree of heat accumulation center at the first target location during the runtime and the output data during the runtime can be specifically achieved by first determining the degree of heat accumulation impact at each moment based on the power attenuation degree and the wavelength redshift degree at each moment, then determining the degree of heat accumulation change at the first target location at multiple moments based on the degree of heat accumulation center at the first target location during the runtime, and finally determining the degree of light output impact of the first target location based on the degree of heat accumulation impact at each moment and the degree of heat accumulation change at multiple moments.

[0063] Wherein, the power reduction value at each moment is the power difference between each moment and the previous moment, the wavelength redshift value at each moment is the ratio of the wavelength at each moment to the reference wavelength, the degree of heat accumulation effect at each moment is positively correlated with the degree of power reduction at each moment and the degree of wavelength redshift at each moment; the degree of heat accumulation change is the difference between the degree of heat accumulation center at each moment and the degree of heat accumulation center at the previous moment, and the first target position is one of the multiple target positions.

[0064] It should be understood that the degree of heat accumulation effect is used to characterize the magnitude of change in the output data. Since the degree of heat accumulation effect at each moment is positively correlated with both the power attenuation and the wavelength redshift at that moment, a higher power attenuation (or a higher wavelength redshift) indicates a higher degree of heat accumulation effect, signifying a greater change in the output data. In one optional implementation, for the acquired power sequence, for any given moment, the power difference between the previous moment and the current moment is denoted as the power decrease index at that moment. This power decrease index is then determined as the power attenuation level, and finally, normalization is performed.

[0065] Alternatively, a window of 2 seconds can be established with that moment as the end, and the average power decrease index of all moments within the window can be recorded as the power reduction degree at that moment, and then normalized.

[0066] In one alternative implementation, for the acquired laser center wavelength sequence, the average wavelength of the first 5 seconds of the sequence can be used as the reference wavelength. For any given moment, the ratio of the wavelength to the reference wavelength is used to determine the wavelength redshift at that moment. Multiple wavelength redshifts are then normalized to obtain the degree of wavelength redshift at each moment.

[0067] Understandably, determining the wavelength redshift based on the ratio between the wavelength and the reference wavelength can more accurately reflect the positive correlation between wavelength change and the degree of wavelength redshift.

[0068] In one optional implementation, for any given moment, the product of the power attenuation and the wavelength redshift can be recorded as the degree of heat accumulation impact at that moment. Changes in the power attenuation (or wavelength redshift) can more clearly reflect the degree of influence on the output data. Since both the power attenuation and wavelength redshift have been normalized, this degree of heat accumulation impact is less than 1, and no further normalization is needed when calculating the heat accumulation impact growth index based on this degree of impact. In another optional implementation, for any target location (e.g., the first target location), a sequence of heat accumulation center degree values ​​for that first target location can be obtained first. The difference between the heat accumulation center degree value at each moment and the heat accumulation center degree value at the previous moment can be recorded as the degree of heat accumulation change at that moment.

[0069] In this embodiment of the application, based on the correlation between the degree of change of the output data at each moment (i.e., the degree of heat accumulation influence) and the degree of heat accumulation change at the target location at each moment (i.e., the degree of heat accumulation change), the influence of the heat accumulation change at the target location on the output data can be obtained.

[0070] Understandably, during the operation of a vertical-cavity surface-emitting laser (VCSEL), localized hot spots are easily generated between the DBR layer and the active layer, leading to an increase in the temperature of the active region and significantly affecting the stability and wavelength of the light output. Among all the target locations acquired, it is necessary to determine which locations are causing the changes in light output due to heat accumulation.

[0071] It should be understood that when the heat accumulation center of a certain hot spot suddenly increases, if the degree of heat accumulation effect on the light output also increases synchronously, it indicates that the hot spot has a significant impact on the power wavelength change of the light output.

[0072] In one alternative implementation, the degree of light output influence at the first target location is determined based on the degree of heat accumulation influence at each moment and the degree of heat accumulation change at multiple moments. Specifically, the first abrupt change moment can be determined first, and then the difference between the degree of heat accumulation influence at the first abrupt change moment and the degree of heat accumulation influence at the previous moment can be used to determine the growth index of heat accumulation influence at the first abrupt change moment. Then, the degree of light output influence at the first target location is determined based on the growth index of heat accumulation influence at the first abrupt change moment and the degree of heat accumulation change at the first abrupt change moment.

[0073] It should be understood that the first abrupt change moment is the moment when the degree of heat accumulation change at the first target location is the greatest, and the heat accumulation effect growth index is used to characterize the degree of influence of the temperature change at the abrupt change moment on the output data.

[0074] Specifically, after obtaining the degree of heat accumulation change at multiple times, the time corresponding to the degree of heat accumulation center with the largest degree of heat accumulation change can be recorded as the first abrupt change time; the difference between the degree of heat accumulation influence corresponding to the first abrupt change time and the degree of heat accumulation influence at the previous time is determined as the heat accumulation influence growth index.

[0075] In one alternative implementation, the degree of influence of light output at the target location satisfies the following formula: in, For the first The degree of influence of light output at each target location; For the first The degree of heat accumulation change of the abrupt heat accumulation element at each target location; This represents the maximum value of the degree of heat accumulation change of the abruptly accumulated heat element at all target locations; For the first The impact of heat accumulation at each target location on the growth index; This represents the maximum value of the growth index of heat accumulation effect at all target locations.

[0076] In this embodiment, by observing the changes in output power and wavelength during a sudden temperature change, the impact of the temperature at that location on the output data can be accurately determined.

[0077] In one alternative implementation, the first deviation index is determined based on the degree of light output influence and the degree of heat accumulation center at each target location, and can be achieved by the following formula: in, For deviation from the index, For the first The degree of heat accumulation center at each target location; The number of target sensors.

[0078] Alternatively, the optimal deviation index can be determined based on the method described above.

[0079] In this embodiment, multiple regions where heat accumulation occurs are first identified. Then, based on the impact of each region where heat accumulation occurs on light output, the degree of reduction in output data caused by the temperature rise of the heat accumulation region can be determined more completely.

[0080] In one implementation of this application, optimal operating data can be obtained based on a simulation model. Specifically, the degree of influence of light output at each position can be determined first; then a simulation model can be constructed based on the degree of influence of light output at each position; based on the simulation model, operating data corresponding to multiple oxide hole diameters can be obtained; then the deviation index of the operating data corresponding to each oxide hole diameter can be determined, and the operating data with the smallest deviation index can be determined as the optimal operating data.

[0081] It is understandable that the degree of influence of light output at each location reflects the intensity of the effect of actual heat accumulation on laser output. Constructing a simulation model in this way can enable the parameter structure of the simulation model to more accurately reflect the coupling relationship between heat flux transmission and light output degradation in real devices.

[0082] Alternatively, the simulation model can be a thermal resistance network model. The following is a specific method for constructing a thermal resistance network model of a vertical cavity surface-emitting laser: The position of each temperature sensor in the distributed temperature sensor array is mapped to the position of the substrate in the thermal resistance network model, with each temperature sensor corresponding to a node. Lateral thermal resistance connections are established between adjacent nodes to form a two-dimensional thermal resistance network. Initially, the thermal resistance of each node is set to... This assumes that heat diffusion is uniform.

[0083] Furthermore, based on the degree of influence of the light output of each temperature sensor, Make corrections.

[0084] The calculation method for the thermal resistance adjustment value of any node satisfies the following formula: In the formula, This is the thermal resistance adjustment value for this node; Preset node thermal resistance; This represents the degree of influence on the light output of this node.

[0085] Understandably, if the larger the value of 𝐴, the greater the impact of that location on light output, the model can reduce the thermal resistance at that location, which is equivalent to making heat flow more easily in that region, thus highlighting its thermal sensitivity.

[0086] The thermal resistance between adjacent nodes satisfies the following formula: In the formula, For the first The node and the first The thermal resistance between adjacent nodes (the first node) The node and the first (each node is an adjacent node) For the first Thermal resistance adjustment value for each node; For the first Thermal resistance adjustment value for each node.

[0087] Finally, the thermal resistance network model is adjusted using adjacent thermal resistances, and then a steady-state simulation is run. It should be understood that steady-state simulation refers to simulating the thermal distribution of a vertical-cavity surface-emitting laser (VCSEL) under the assumption that the system's heat input and output are in equilibrium and the temperature no longer changes over time. The results obtained are the temperature fields of each region when it is stable.

[0088] Understandably, the above steps are based on data collected by the sensor array on the substrate plane to construct a non-uniform thermal resistance network model in two-dimensional space. By weighting the thermal resistance of each node through the degree of influence of light output, the model can map the sensitivity of the thermal impact on performance in different regions. Thus, even in the absence of complete vertical thermal structure information, it is still possible to assess and predict the thermal stability risk areas of the device, making the degree of heat accumulation center of the local heat accumulation sensor more accurate during the simulation process.

[0089] It should be understood that oxide orifices are key structures that determine the effectiveness of lateral heat dissipation paths and the distribution of heat flux. The size of the orifice directly affects the location of heat flow bottlenecks, the size of heat accumulation areas, and the degree of thermal resistance concentration. If the orifice size is too small, it will lead to a narrow heat flow path, significant heat accumulation, and large attenuation of light output. If the orifice size is too large, although the heat flux path is wider, the current density will be reduced, and the edge areas will be difficult to dissipate heat effectively, resulting in edge heat accumulation. The wavelength redshift will be aggravated again, the light output will be unstable, and the impact of heat accumulation will increase.

[0090] To further analyze the dominant role of oxide pore size in thermal behavior and determine the optimal oxide pore size, the influence of oxide pore size variation on thermal diffusivity can be systematically evaluated based on the optimized simulation model.

[0091] Specifically, based on this simulation model, steady-state simulations were performed on the pore sizes of multiple oxide pores, with other parameters remaining constant, to obtain operational data for each oxide pore size. Based on the operational data for each pore size, the deviation index for each oxide pore size was obtained.

[0092] Based on the description of the above embodiments, it should be understood that a smaller deviation index indicates better heat dissipation performance and a better oxide pore diameter. The smallest deviation index can be determined as the optimal deviation index, the oxide pore diameter corresponding to the smallest deviation index can be determined as the optimal oxide pore diameter, and the operating data with the smallest deviation index can be determined as the optimal operating data.

[0093] For example, the set oxide pore size can be 3μm, 5μm, 7μm, 10μm, or 13μm.

[0094] It should be understood that by performing steady-state simulations based on this simulation model and keeping other parameters constant, the operating data for the pore size of each oxide pore can be obtained, allowing for comparison with single variables, and the simulation results are more accurate.

[0095] Optionally, for any oxide hole diameter, the degree of light output influence and heat accumulation center degree at all target locations can be obtained through steady-state simulation 10 seconds after the start of the steady-state simulation, and then the deviation value can be obtained.

[0096] Alternatively, the aperture size of the oxide hole of the actual vertical cavity surface-emitting laser can be simulated in a steady state on the simulation model, and the influence of the optical output, the degree of heat accumulation center, and the first deviation index of the vertical cavity surface-emitting laser can be calculated based on the data obtained from the steady state simulation.

[0097] S202. Determine the degree of heat accumulation in the aperture based on the first deviation index and the optimal deviation index.

[0098] In one optional implementation, the aperture size of the oxide hole of the vertical cavity surface emitter (VCSEL) and the aperture size of the oxide hole corresponding to the optimal operating data can be obtained; then, based on the difference between the aperture size of the VCSEL and the aperture size of the oxide hole corresponding to the optimal operating data, and the difference between the first deviation index and the optimal deviation index, the degree of heat accumulation of the aperture can be determined.

[0099] Optionally, the degree of heat accumulation at this aperture satisfies the following formula: in, The degree of heat accumulation at the aperture; This refers to the aperture size of the oxide hole in the vertical cavity surface-emitting laser. The optimal pore size for oxide pores; This is the first deviation index; This is the optimal deviation index.

[0100] As can be seen from the above formula, The larger the value, the greater the deviation between the oxide aperture diameter of the current actual vertical-cavity surface-emitting laser and the optimal oxide aperture diameter size; at the same time, if... The larger the value, the greater the heat accumulation effect caused by the deviation of the oxide pores, and therefore the greater the degree of heat accumulation in the pore size.

[0101] In an alternative implementation, the difference between the first deviation index and the optimal deviation index can also be used to determine the degree of heat accumulation in the aperture.

[0102] In this embodiment, since the difference between the actual operating data of the vertical cavity surface-emitting laser and the vertical cavity surface-emitting laser of the optimal size lies in the oxide aperture size and operating data, the difference between the operating data of the vertical cavity surface-emitting laser and the operating data of the laser with the best heat dissipation performance can be obtained more accurately based on the difference between the size difference and the deviation index.

[0103] In one implementation of this application, while an inappropriate oxide aperture size is a significant, but not the only, reason for poor heat dissipation performance of a vertical-cavity surface-emitting laser (VCSEL), it is necessary to reduce the confidence level of the evaluation results based on the aperture heat accumulation degree, i.e., the oxide aperture confidence level. This oxide aperture confidence level characterizes the degree of influence of the oxide aperture size on heat dissipation performance.

[0104] It should be understood that when the main cause is not the oxide hole diameter, the change in the degree of heat accumulation center of the sensor caused by the non-oxide hole diameter problem will be small when the oxide hole diameter is adjusted during the simulation. In this case, it is necessary to determine the confidence level of the oxide hole.

[0105] Optionally, the confidence level of the oxide pore can be determined based on the ratio between the highest temperature difference at each location and the maximum value of the highest temperature differences at the multiple locations.

[0106] Optionally, the confidence level of the oxide pores satisfies the following formula: in, Confidence level for oxide pores; The number of target locations for a vertical-cavity surface-emitting laser; For the first vertical cavity surface-emitting laser The difference between the highest and lowest temperatures at each target location during the entire oxide hole size adjustment process; This represents the maximum value of the difference between the highest and lowest temperatures at all target locations throughout the entire oxide pore size adjustment process.

[0107] It should be understood that if the pore size of the oxide pores is the dominant factor, the temperature at the target location will change significantly during pore size adjustment; however, if the pore size is not the dominant factor, there will be no significant change. Furthermore, if it is not the dominant factor, adjusting the pore size will generate actual heat accumulation due to pore size issues. Therefore, the following approach is adopted... right Normalization is performed to determine the confidence level of oxide pore dominance.

[0108] After obtaining the confidence level of the oxide pores, the heat dissipation performance problem caused by the oxide pore diameter problem can be evaluated based on the confidence level of the oxide pores.

[0109] In one alternative implementation, the heat dissipation score of the vertical cavity surface-emitting laser can be determined based on the confidence level of the oxide aperture and the degree of heat accumulation in the aperture.

[0110] Alternatively, the product of the oxide hole confidence level and the degree of heat accumulation in the hole diameter can be used to determine the heat dissipation score of the vertical cavity surface-emitting laser.

[0111] Understandably, when the heat dissipation score is greater than the heat dissipation score threshold, it indicates that the aperture heat accumulation of the vertical-cavity surface-emitting laser (VCSEL) is high, and the heat dissipation performance of the VCSEL is poor. When the heat dissipation score is less than or equal to the heat dissipation score threshold, it indicates that the aperture heat accumulation of the VCSEL is low. If the heat accumulation center degree is also low at all locations, it indicates that the heat dissipation performance of the VCSEL is good. If there are locations with high heat accumulation center degree, it indicates that other factors are causing the poor heat dissipation performance of the VCSEL.

[0112] For example, the heat dissipation score threshold can be 0.3.

[0113] In an alternative implementation, the difference between 1 and the product of the oxide aperture dominance confidence level and the aperture heat accumulation degree can be determined as the heat dissipation score of the vertical-cavity surface-emitting laser (VCSEL). A new heat dissipation score threshold is then set. In this case, if the heat dissipation score is less than the threshold, it indicates that the aperture heat accumulation degree of the VCSEL is high, and the heat dissipation performance of the VCSEL is poor. If the heat dissipation score is greater than or equal to the threshold, it indicates that the aperture heat accumulation degree of the VCSEL is low. If the heat accumulation center degree is also low at all locations, it indicates that the heat dissipation performance of the VCSEL is good. If there are locations with high heat accumulation center degrees, it indicates that other factors are causing the poor heat dissipation performance of the VCSEL.

[0114] For example, the heat dissipation score threshold can be 0.7 in this case.

[0115] The following example illustrates a method for evaluating the heat dissipation performance of a VCSEL laser provided in this application.

[0116] For example, such as Figure 3 As shown, the method for evaluating the heat dissipation performance of a VCSEL laser includes S301-S309.

[0117] S301. Obtain the local heat accumulation sensor and the degree of its heat accumulation center.

[0118] It should be understood that the location of the local heat accumulation sensor is the target location, and the degree of heat accumulation at the center of the local heat accumulation sensor is the degree of heat accumulation at the target location.

[0119] S302. The degree of heat accumulation effect is obtained based on the light output power and redshift.

[0120] Specifically, the degree of heat accumulation effect is determined based on the output power and wavelength in the output data.

[0121] S303. Based on the coordination relationship between the degree of heat accumulation center and the degree of heat accumulation influence, the degree of light output influence is obtained.

[0122] S304. Adjust the simulation model according to the degree of influence of light output and perform simulation.

[0123] Specifically, steady-state simulations were performed on multiple oxide pore diameters to obtain operational data for each oxide pore diameter.

[0124] S305. Based on the degree of influence of light output and the degree of heat accumulation center in the simulation, the first deviation index is obtained.

[0125] Specifically, the aperture size of the oxide hole in the actual vertical cavity surface-emitting laser was also simulated, and the first deviation index was obtained based on the simulation data.

[0126] S306. Obtain the optimal oxide pore size in the simulation.

[0127] That is, the pore size of the oxide pore corresponding to the smallest deviation index.

[0128] S307, Obtain the degree of heat accumulation at the aperture.

[0129] Specifically, the degree of heat accumulation at this aperture is obtained based on the first deviation index and the minimum deviation index.

[0130] S308. Determine the confidence level of the oxide pores.

[0131] S309. Obtain the heat dissipation score of the vertical cavity surface-emitting laser.

[0132] Specifically, the heat dissipation score of the vertical cavity surface-emitting laser is obtained based on the confidence level of the oxide hole and the degree of heat accumulation of the hole.

[0133] The descriptions in S301-S309 above, by obtaining operational data from the actual process to calculate the degree of heat accumulation center, and then correcting the simulation model, improve the accuracy of the degree of heat accumulation center in the simulation model. Regarding the determination of the change in the degree of heat accumulation caused by the aperture, the embodiments of this application use multiple aperture schemes to determine the optimal aperture, and obtain the degree of aperture heat accumulation based on the difference between the current aperture and the optimal aperture and the difference in effect. Based on the temperature change of the sensor, the credibility of the heat accumulation caused by the oxide aperture is obtained. Thus, the heat dissipation performance of the oxide aperture of the vertical cavity surface-emitting laser can be comprehensively judged, improving the accuracy and comprehensiveness of the heat dissipation performance evaluation of the vertical cavity surface-emitting laser.

[0134] This application also proposes a heat dissipation performance evaluation system for a VCSEL laser, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of any one of the heat dissipation performance evaluation methods for a VCSEL laser.

[0135] It should be noted that the heat dissipation performance evaluation system for a VCSEL laser provided in this application embodiment and the heat dissipation performance evaluation method for a VCSEL laser provided in the above embodiment belong to the same concept, and will not be repeated here.

[0136] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0137] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A method for evaluating the heat dissipation performance of a VCSEL laser, characterized in that, The method includes: Obtain the operating data and optimal operating data of the vertical cavity surface-emitting laser. The optimal operating data is the operating data of the laser with the best heat dissipation performance. The operating data includes the temperature at multiple locations during the operating period and the output data during the operating period. The output data includes the output power and wavelength. Based on the operating data of the vertical cavity surface-emitting laser and the optimal operating data, the aperture heat accumulation degree is determined, which is used to characterize the difference between the operating data of the vertical cavity surface-emitting laser and the optimal operating data; The heat dissipation performance of the vertical cavity surface-emitting laser is evaluated based on the degree of heat accumulation at the aperture.

2. The method for evaluating the heat dissipation performance of a VCSEL laser according to claim 1, characterized in that, The determination of aperture heat accumulation based on the operating data of the vertical-cavity surface-emitting laser and the optimal operating data includes: A first deviation index is determined based on the operating data of the vertical cavity surface-emitting laser, and an optimal deviation index is determined based on the optimal operating data. The first deviation index is the deviation index of the vertical cavity surface-emitting laser. A deviation index is used to characterize the degree of temperature increase and the degree of weakening of the output data at the multiple locations during the operating period. The degree of heat accumulation in the aperture is determined based on the first deviation index and the optimal deviation index.

3. The method for evaluating the heat dissipation performance of a VCSEL laser according to claim 2, characterized in that, The determination of the first deviation index based on the operating data of the vertical-cavity surface-emitting laser includes: Based on the temperature at multiple locations within the runtime segment, the heat accumulation center degree of multiple target locations within the runtime segment is determined. The heat accumulation center degree of a target location is used to characterize the temperature level within a target area. A target area includes a target location and its adjacent locations. The temperature of the target location is greater than the temperature of its adjacent locations. Based on the degree of heat accumulation center at multiple target locations within the runtime period and the output data within the runtime period, the degree of light output influence at each target location is determined, wherein the degree of light output influence at the target location is used to characterize the impact of temperature changes at the target location on the output data; The first deviation index is determined based on the degree of light output influence at each target location and the degree of heat accumulation center at each target location.

4. The method for evaluating the heat dissipation performance of a VCSEL laser according to claim 3, characterized in that, Based on the degree of heat accumulation center at the first target location during the runtime period and the output data during the runtime period, the degree of influence of light output at the first target location is determined, including: Based on the degree of power reduction and the degree of wavelength redshift at each moment, the degree of heat accumulation effect at each moment is determined. The power reduction value at each moment is the power difference between each moment and the previous moment. The wavelength redshift value at each moment is the ratio of the wavelength at each moment to the reference wavelength. The degree of heat accumulation effect at each moment is positively correlated with both the degree of power reduction and the degree of wavelength redshift at each moment. The degree of heat accumulation change at the first target location is determined based on the degree of heat accumulation center at the first target location during the runtime period. The degree of heat accumulation change is the difference between the degree of heat accumulation center at each time and the degree of heat accumulation center at the previous time. The first target location is one of the multiple target locations. The degree of influence of heat accumulation at each moment and the degree of change of heat accumulation at multiple moments are used to determine the degree of influence of light output at the first target location.

5. The method for evaluating the heat dissipation performance of a VCSEL laser according to claim 4, characterized in that, Determining the degree of influence of heat accumulation on the light output at the first target location based on the degree of heat accumulation influence at each time moment and the degree of heat accumulation change at multiple times includes: Determine the first mutation moment, which is the moment when the degree of heat accumulation change at the first target location is the greatest; The difference between the degree of heat accumulation effect at the first abrupt change and the degree of heat accumulation effect at the previous time is used to determine the heat accumulation effect growth index at the first abrupt change. The heat accumulation effect growth index is used to characterize the degree of influence of the temperature change at the abrupt change on the output data. The degree of influence of heat accumulation on the first target location is determined based on the growth index of heat accumulation at the first abrupt change and the degree of heat accumulation change at the first abrupt change.

6. The method for evaluating the heat dissipation performance of a VCSEL laser according to claim 2, characterized in that, The determination of the pore size heat accumulation degree based on the first deviation index and the optimal deviation index includes: Obtain the oxide aperture size of the vertical cavity surface-emitting laser and the oxide aperture size corresponding to the optimal operating data; The degree of heat accumulation in the aperture is determined based on the difference between the aperture size of the oxide aperture of the vertical cavity surface emitter laser and the aperture size of the oxide aperture corresponding to the optimal operating data, and the difference between the first deviation index and the optimal deviation index.

7. The method for evaluating the heat dissipation performance of a VCSEL laser according to claim 1, characterized in that, To obtain optimal operating data, including: A simulation model is constructed based on the degree of influence of the light output at each position of the vertical cavity surface-emitting laser. Based on the simulation model, operational data corresponding to the pore size of multiple oxide pores were obtained; Determine the deviation index of the operating data corresponding to each oxide pore size; The running data with the smallest deviation from the exponent is determined as the optimal running data.

8. The method for evaluating the heat dissipation performance of a VCSEL laser according to claim 1, characterized in that, The evaluation of the heat dissipation performance of the vertical-cavity surface-emitting laser based on the degree of heat accumulation at the aperture includes: The heat dissipation score of the vertical cavity surface-emitting laser is determined based on the confidence level of the oxide hole and the degree of heat accumulation of the hole diameter. The confidence level of the oxide hole is used to characterize the degree of influence of the size of the oxide hole diameter on the heat dissipation performance. When the heat dissipation score is greater than the heat dissipation score threshold, the heat dissipation performance of the vertical cavity surface-emitting laser is determined to be poor.

9. The method for evaluating the heat dissipation performance of a VCSEL laser according to claim 8, characterized in that, The determination of the confidence level of the oxide pore includes: The confidence level of the oxide pore is determined based on the ratio between the highest temperature difference at each location and the maximum value of the highest temperature differences at the plurality of locations.

10. A system for evaluating the heat dissipation performance of a VCSEL laser, characterized in that, The device includes a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor executes the computer program to implement the steps of the method for evaluating the heat dissipation performance of a VCSEL laser as described in any one of claims 1-9.

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