Method for testing junction temperature of semiconductor laser
By measuring the characteristic peak wavelength of a semiconductor laser at different temperatures and establishing a linear relationship, the complexity and accuracy problems of junction temperature testing of semiconductor lasers in the prior art are solved, and simplified operation and high-precision junction temperature testing are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI XINWEI SEMICON CO LTD
- Filing Date
- 2026-03-27
- Publication Date
- 2026-06-09
AI Technical Summary
Existing methods for testing junction temperature of semiconductor lasers are costly, complex to operate, and have poor testing accuracy. In particular, software model simulation methods are computationally complex and have large errors, while narrow pulse current methods have low accuracy in different operating modes.
By obtaining the threshold current of a semiconductor laser at a preset temperature, and measuring the characteristic peak wavelength using DC current at multiple different temperatures, a linear relationship is established. Then, the junction temperature is determined based on the characteristic peak wavelength, simplifying the testing process and improving accuracy.
The process for testing the junction temperature of semiconductor lasers has been simplified. It is easy and practical to operate, and the test results are intuitive, accurate and highly repeatable, reducing the accuracy requirements of the equipment and the testing cost.
Smart Images
Figure CN122171167A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor technology, and in particular to a method for testing the junction temperature of a semiconductor laser. Background Technology
[0002] With the widespread application of semiconductor lasers in consumer electronics, communications, and automotive fields, the requirements for their performance and reliability are becoming increasingly stringent. To more accurately assess the reliability level of lasers, higher demands are placed on the accuracy and convenience of junction temperature testing for semiconductor lasers. Currently, the junction temperature of semiconductor lasers is mainly tested using software model simulation or the narrow-pulse current method. However, these methods have several drawbacks that affect the test results. For example, software model simulation is computationally complex, requires a high level of theoretical knowledge from personnel, and the simulation results are prone to significant errors due to small parameter deviations. Furthermore, it requires expensive specialized software. The narrow-pulse current method calculates the temperature by measuring the wavelength change caused by the junction temperature of the semiconductor laser. However, the operating mode of a semiconductor laser under narrow-pulse current differs from that under conventional DC conditions, and the control precision of narrow-pulse current is typically lower than that of DC current, making accurate calculation difficult. Therefore, current methods for testing the junction temperature of semiconductor lasers suffer from high costs, complex operations, and poor testing accuracy. Summary of the Invention
[0003] The purpose of this invention is to provide a method for testing the junction temperature of a semiconductor laser, so as to simplify the junction temperature testing of semiconductor lasers and improve the accuracy of the junction temperature testing of semiconductor lasers.
[0004] To achieve the above objectives, the present invention provides a method for testing the junction temperature of a semiconductor laser, comprising:
[0005] Provide semiconductor lasers;
[0006] Obtain the threshold current of the semiconductor laser at a preset temperature;
[0007] The first characteristic peak wavelength of the semiconductor laser is obtained under a first test current condition at multiple different first test temperatures, wherein the first test current is less than the threshold current.
[0008] Based on all the obtained first characteristic peak wavelengths, obtain a linear relationship between the first characteristic peak wavelength of the semiconductor laser under the first test current condition and the junction temperature.
[0009] Obtain the second characteristic peak wavelength of a semiconductor laser at a second test temperature under a second test current condition, wherein the second test current is greater than or equal to the threshold current.
[0010] Based on the linear relationship, the junction temperature corresponding to the second characteristic peak wavelength is determined to obtain the junction temperature of the active region of the semiconductor laser at the second test temperature under the second test current condition.
[0011] Optionally, in the junction temperature testing method for the semiconductor laser, both the first test current and the second test current are direct current.
[0012] Optionally, in the junction temperature test method for the semiconductor laser, before obtaining the threshold current of the semiconductor laser at a preset temperature, the method further includes: placing the semiconductor laser on the surface of a test fixture.
[0013] Optionally, in the junction temperature testing method for the semiconductor laser, the method for obtaining the threshold current of the semiconductor laser at a preset temperature includes:
[0014] The test fixture is set to the preset temperature, and the semiconductor laser is scanned under different scanning currents;
[0015] The output power of the semiconductor laser at different scanning currents is obtained, and the threshold current of the semiconductor laser is obtained based on the output power.
[0016] Optionally, in the junction temperature testing method for the semiconductor laser, the step size of the scanning current is 0.01mA-1mA.
[0017] Optionally, in the junction temperature testing method for the semiconductor laser, all different first test temperatures include sequentially increasing first sub-test temperatures up to the Nth sub-test temperature, where 5 ≤ N ≤ 10, and N is an integer.
[0018] Optionally, in the junction temperature testing method for the semiconductor laser, the second test temperature is greater than or equal to the first sub-test temperature and less than or equal to the Nth sub-test temperature.
[0019] Optionally, in the junction temperature test method for the semiconductor laser, the first test current is 5%-20% of the threshold current, and the second test current is 10 mA-100 mA.
[0020] Optionally, in the junction temperature test method for the semiconductor laser, the first characteristic peak wavelengths of the semiconductor laser at multiple different first test temperatures under the first test current condition are linearly fitted to obtain the linear relationship.
[0021] Optionally, in the junction temperature testing method for the semiconductor laser, the semiconductor laser includes a Fabry-Perot laser, a distributed feedback semiconductor laser, and a vertical-cavity surface-emitting semiconductor laser.
[0022] In the junction temperature testing method for semiconductor lasers provided by this invention, the threshold current of the semiconductor laser at a preset temperature is first obtained. Then, the first characteristic peak wavelengths corresponding to the semiconductor laser at multiple different first test temperatures under a first test current condition are obtained, wherein the first test current is less than the threshold current. Next, based on all the obtained first characteristic peak wavelengths, a linear relationship between the first characteristic peak wavelength of the semiconductor laser under the first test current condition and the junction temperature is obtained. Then, the second characteristic peak wavelength of the semiconductor laser at a second test temperature under a second test current condition is obtained, wherein the second test current is greater than or equal to the threshold current. Afterward, based on the linear relationship, the junction temperature corresponding to the second characteristic peak wavelength is determined to obtain the junction temperature of the active region of the semiconductor laser under the second test current condition and at a second test temperature environment. This simplifies the junction temperature testing process for semiconductor lasers, is simple and practical to operate, and provides intuitive, accurate, and highly repeatable test results, thereby improving testing accuracy. Attached Figure Description
[0023] Figure 1 This is a schematic flowchart of the junction temperature testing method for a semiconductor laser according to an embodiment of the present invention;
[0024] Figure 2 This is a schematic diagram of the threshold current scan curve of a semiconductor laser when the test fixture is at a preset temperature;
[0025] Figure 3 This is a schematic diagram illustrating the linear relationship between the characteristic peak wavelength of a semiconductor laser and its junction temperature. Detailed Implementation
[0026] The junction temperature testing method for semiconductor lasers proposed in this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise scales, used only to facilitate and clarify the illustration of the embodiments of this invention. Furthermore, the structures shown in the drawings are often part of the actual structure. In particular, different figures may emphasize different aspects and sometimes use different scales.
[0027] Figure 1 This is a schematic flowchart of a method for testing the junction temperature of a semiconductor laser according to an embodiment of the present invention. Figure 1 As shown, the junction temperature testing method for semiconductor lasers provided in this embodiment includes:
[0028] Step S1: Provide a semiconductor laser;
[0029] Step S2: Obtain the threshold current of the semiconductor laser at a preset temperature;
[0030] Step S3: Obtain the first characteristic peak wavelength of the semiconductor laser at multiple different first test temperatures under the first test current condition, wherein the first test current is less than the threshold current;
[0031] Step S4: Based on all the obtained first characteristic peak wavelengths, obtain the linear relationship between the first characteristic peak wavelength of the semiconductor laser and the junction temperature under the first test current condition;
[0032] Step S5: Obtain the second characteristic peak wavelength of the semiconductor laser at the second test temperature under the second test current condition, wherein the second test current is greater than or equal to the threshold current;
[0033] Step S6: Determine the junction temperature corresponding to the second characteristic peak wavelength according to the linear relationship, so as to obtain the junction temperature of the active region of the semiconductor laser under the second test current condition in the second test environment.
[0034] Figure 2 This is a schematic diagram of the threshold current scan curve of a semiconductor laser when the test fixture is at a preset temperature; Figure 3 This is a schematic diagram illustrating the linear relationship between the characteristic peak wavelength of a semiconductor laser and its junction temperature. The following section will refer to the appendix... Figure 2 and Figure 3 The junction temperature testing method for semiconductor lasers provided in this embodiment will be described in more detail.
[0035] In step S1, a semiconductor laser is provided. Specifically, the semiconductor laser includes a Fabry-Perot laser (FP), a distributed feedback semiconductor laser (DFB), and a vertical-cavity surface-emitting semiconductor laser (VCSEL).
[0036] Then, step S2 is performed to obtain the threshold current of the semiconductor laser at a preset temperature.
[0037] In this embodiment, before obtaining the threshold current of the semiconductor laser at a preset temperature, the method further includes: placing the semiconductor laser on the surface of a test fixture.
[0038] Specifically, the method for obtaining the threshold current of the semiconductor laser at a preset temperature includes:
[0039] First, the test fixture is set to the preset temperature to expose the semiconductor laser within this environment. The semiconductor laser is then scanned at different scanning currents to obtain the output power of the semiconductor laser at these different scanning currents. The preset temperature can be between 30°C and 50°C, for example, 40°C.
[0040] Then, the output power (i.e., the power of light emitted by the semiconductor laser) of the semiconductor laser at different scanning currents is obtained, and the threshold current of the laser is obtained based on the output power, thereby obtaining the critical current at which the semiconductor laser begins lasing. Specifically, after obtaining the output power of the semiconductor laser at different scanning currents, a curve relating the output power to the current can be formed, and the threshold current can be determined based on the inflection point of this curve (or the point of abrupt change in the output power).
[0041] like Figure 2 As shown, Figure 2 The horizontal axis represents the scanning current in mA, and the vertical axis represents the power in mW. The scanning current can be in increments of 0.01 mA to 1 mA. The scanning current can range from 0 mA to the safe operating current limit of the semiconductor laser, and the scanning current is a direct current.
[0042] Next, step S3 is executed to obtain the first characteristic peak wavelength of the semiconductor laser at multiple different first test temperatures under the first test current condition, wherein the first test current is less than the threshold current. The first characteristic peak wavelength of the semiconductor laser refers to the wavelength value with the highest intensity in the output spectrum of the semiconductor laser under the first test current condition at the first test temperature environment.
[0043] In this embodiment, the first test current is a direct current, and the first test current is 5%-20% of the threshold current, for example, 10% or 15%. In this way, the self-heating of the semiconductor laser under the first test current is reduced, thereby reducing the impact of the self-heating of the semiconductor laser, or even making it negligible, so that the junction temperature of the active region of the semiconductor laser is equal to the ambient temperature (i.e., the first test temperature), thereby improving the test accuracy.
[0044] Furthermore, compared to narrow pulse current, using DC current for the first test current can improve the testing accuracy of semiconductor lasers, which is beneficial for accurate calculations, while reducing the requirements for equipment accuracy, thereby effectively reducing testing costs.
[0045] In this embodiment, the first test temperature is the ambient temperature of the semiconductor laser, i.e., the first test temperature is the temperature of the test fixture. Specifically, all different first test temperatures include sequentially increasing first sub-test temperatures up to the Nth sub-test temperature, where N is an integer, and 5≤N≤10, preferably 6≤N≤9. This balances fitting accuracy and testing efficiency, avoiding the impact on testing efficiency due to a large number of test temperature points, and avoiding errors due to a small number of test temperature points, thereby avoiding affecting testing accuracy.
[0046] Furthermore, one of the sub-temperatures from the first sub-test temperature to the Nth sub-test temperature can be equal to the preset temperature.
[0047] For example, the first sub-test temperature can be 30℃~50℃.
[0048] For example, in the range from the first sub-test temperature to the Nth sub-test temperature, N=7, and the first sub-test temperature is 30℃, then the first sub-test temperature to the Nth sub-test temperature are 30℃, 40℃, 50℃, 60℃, 70℃, 80℃ and 90℃ respectively.
[0049] In this embodiment, a spectrometer can be used to obtain the first characteristic peak wavelength of the semiconductor laser at multiple different first test temperatures under the first test current condition. Specifically, firstly, the test fixture holding the semiconductor laser is sequentially set to multiple different first test temperatures, and the first test current output by the current source meter is applied to the semiconductor laser; then, the spectrometer is turned on to obtain the first characteristic peak wavelength of the emitted light from the semiconductor laser at multiple different first test temperatures.
[0050] Next, step S4 is executed to obtain a linear relationship between the first characteristic peak wavelength of the semiconductor laser and the junction temperature under the first test current condition, based on all the obtained first characteristic peak wavelengths.
[0051] Specifically, the first characteristic peak wavelengths of the semiconductor laser obtained under the first test current condition at multiple different first test temperatures are linearly fitted to obtain the linear relationship.
[0052] It should be noted that under the first test current condition, the junction temperature of the active region of the semiconductor laser can be approximately equal to the ambient temperature. Specifically, the junction temperature of a semiconductor laser is usually the sum of the ambient temperature and the temperature rise caused by the laser's own heat generation. Since the first test current is less than the threshold current, the heat generated by the semiconductor laser under the first test current condition is minimal, and the resulting temperature rise is negligible. Therefore, the junction temperature at this time can be directly regarded as equal to the ambient temperature, i.e., the first test temperature set by the test fixture.
[0053] like Figure 3 As shown, Figure 3 The horizontal axis represents temperature, specifically the junction temperature of the semiconductor laser, in °C, and the vertical axis represents wavelength in nm. For example, the linear relationship between the characteristic peak wavelength of a semiconductor laser and its junction temperature is: y = 0.0601x + 856.48, where y represents the characteristic peak wavelength and x represents the junction temperature of the semiconductor laser.
[0054] Next, step S5 is executed to obtain the second characteristic peak wavelength of the semiconductor laser at the second test temperature under the second test current condition.
[0055] In this embodiment, the second test current can be 10 mA-100 mA, such as 20 mA, 30 mA, 40 mA, 50 mA or 80 mA.
[0056] In this embodiment, the method for obtaining the second characteristic peak wavelength of a semiconductor laser at a second test temperature under a second test current condition includes: firstly, setting the test fixture on which the semiconductor laser is placed to the second test temperature. The second test temperature is greater than or equal to the first sub-test temperature and less than or equal to the Nth sub-test temperature.
[0057] In this embodiment, the second test temperature can be 70℃~90℃, for example 80℃.
[0058] Then, a second test current is applied to the semiconductor laser using a current source meter, and a spectrometer is used to obtain the second characteristic peak wavelength of the light emitted by the semiconductor laser.
[0059] In this embodiment, the second test current is a DC current, and the second test current is greater than or equal to the threshold current.
[0060] Next, step S6 is executed to determine the junction temperature corresponding to the second characteristic peak wavelength based on the linear relationship, so as to obtain the junction temperature of the active region of the semiconductor laser under the second test current condition and at the second test temperature. This simplifies the junction temperature testing process for semiconductor lasers, eliminating the need for complex theories and testing equipment. The operation is simple and practical, and the test results are intuitive, accurate, and highly repeatable, thereby improving test accuracy.
[0061] Specifically, the method for determining the junction temperature corresponding to the second characteristic peak wavelength according to the linear relationship includes: substituting the second characteristic peak wavelength into the linear relationship to obtain the junction temperature corresponding to the second characteristic peak wavelength, thereby obtaining the junction temperature of the active region of the semiconductor laser under the second test current condition and in the second test temperature environment.
[0062] In summary, the junction temperature testing method for semiconductor lasers provided in this invention first obtains the threshold current of the semiconductor laser at a preset temperature; then, it obtains the first characteristic peak wavelengths of the semiconductor laser at multiple different first test temperatures under a first test current condition, wherein the first test current is less than the threshold current; next, based on all the obtained first characteristic peak wavelengths, it obtains a linear relationship between the first characteristic peak wavelength of the semiconductor laser under the first test current condition and the junction temperature; then, it obtains the second characteristic peak wavelength of the semiconductor laser at a second test temperature under a second test current condition, wherein the second test current is greater than or equal to the threshold current; finally, based on the linear relationship, it determines the junction temperature corresponding to the second characteristic peak wavelength to obtain the junction temperature of the active region of the semiconductor laser at the second test temperature under the second test current condition. This simplifies the junction temperature testing process for semiconductor lasers, is simple and practical to operate, and provides intuitive, accurate, and highly repeatable test results, thereby improving testing accuracy.
[0063] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to mutually. In addition, different parts between embodiments can also be combined with each other, and this invention does not limit this.
[0064] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.
Claims
1. A method for testing the junction temperature of a semiconductor laser, characterized in that, include: Provide semiconductor lasers; Obtain the threshold current of the semiconductor laser at a preset temperature; The first characteristic peak wavelength of the semiconductor laser is obtained under a first test current condition at multiple different first test temperatures, wherein the first test current is less than the threshold current. Based on all the obtained first characteristic peak wavelengths, obtain a linear relationship between the first characteristic peak wavelength of the semiconductor laser under the first test current condition and the junction temperature. Obtain the second characteristic peak wavelength of a semiconductor laser at a second test temperature under a second test current condition, wherein the second test current is greater than or equal to the threshold current. Based on the linear relationship, the junction temperature corresponding to the second characteristic peak wavelength is determined to obtain the junction temperature of the active region of the semiconductor laser at the second test temperature under the second test current condition.
2. The junction temperature testing method for a semiconductor laser as described in claim 1, characterized in that, Both the first test current and the second test current are direct current.
3. The junction temperature testing method for a semiconductor laser as described in claim 1, characterized in that, Before obtaining the threshold current of the semiconductor laser at a preset temperature, the method further includes: placing the semiconductor laser on the surface of a test fixture.
4. The junction temperature testing method for a semiconductor laser as described in claim 3, characterized in that, A method for obtaining the threshold current of the semiconductor laser at a preset temperature includes: The test fixture is set to the preset temperature, and the semiconductor laser is scanned under different scanning currents; The output power of the semiconductor laser at different scanning currents is obtained, and the threshold current of the semiconductor laser is obtained based on the output power.
5. The junction temperature testing method for a semiconductor laser as described in claim 4, characterized in that, The scanning current increment is 0.01mA-1mA.
6. The method for testing the junction temperature of a semiconductor laser as described in claim 1, characterized in that, All different first test temperatures include sequentially increasing first sub-test temperatures up to the Nth sub-test temperature, where 5 ≤ N ≤ 10, and N is an integer.
7. The junction temperature testing method for a semiconductor laser as described in claim 6, characterized in that, The second test temperature is greater than or equal to the first sub-test temperature and less than or equal to the Nth sub-test temperature.
8. The method for testing the junction temperature of a semiconductor laser as described in claim 1, characterized in that, The first test current is 5%-20% of the threshold current, and the second test current is 10 mA-100 mA.
9. The method for testing the junction temperature of a semiconductor laser as described in claim 1, characterized in that, The obtained first characteristic peak wavelengths of the semiconductor laser at multiple different first test temperatures under the first test current condition are linearly fitted to obtain the linear relationship.
10. The method for testing the junction temperature of a semiconductor laser as described in any one of claims 1-9, characterized in that, The semiconductor lasers include Fabry-Perot lasers, distributed feedback semiconductor lasers, and vertical-cavity surface-emitting semiconductor lasers.