Test method for evaluating service life of pump laser for hundred-milliwatt-level submarine optical communication

Abstract

The invention relates to a test method for evaluating the service life of a pump laser for hundred milliwatt-level submarine optical communication, and belongs to the technical field of pump lasers for optical communication. The overall thought of the invention is as follows: as the chip is a weak link restricting the service life of the pump laser, the activation energy and the current acceleration factor in a chip service life model are approximately equal to the activation energy and the current acceleration factor in a service life model of a module; therefore, multiple groups of accelerated aging life tests of the chip under different conditions are utilized to replace accelerated aging tests of multiple groups of modules, activation energy and current acceleration factors in the life model are obtained, and the test difficulty and cost are greatly reduced. Besides, a method of simultaneous acceleration under various conditions is adopted in the life model, for example, temperature acceleration and current acceleration are carried out at the same time, the number of samples is increased, and the test time can be reduced from 8000-5000h to 4000-2000h. The test method can greatly save cost and time, and provides a thought for evaluating the service life of the product more conveniently and quickly in the stages of product pre-research, prototype sample and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of pump lasers for optical communication, and in particular relates to a test method for evaluating the life of a pump laser for submarine optical communication at the hundred-milliwatt level. Background Art

[0002] Submarine optical communication has replaced submarine electrical communication in large quantities with its advantages of large capacity, low loss, no electromagnetic interference, safety and reliability, and has become an important means of contemporary international communication. It is also of great significance to the development of national defense security and military defense. Underwater optical repeaters are the most important equipment in the relay submarine cable system, which are laid on the seabed with a depth of several hundred meters or up to eight thousand meters. Under such conditions, once maintenance is required, the cost is extremely high, so high requirements are placed on the reliability of the equipment. The service life of the submarine optical repeater should not be less than 25 years (T / GDACERCU 0002-2019 Technical Requirements for Submarine Optical Repeaters). As a key optical device in the repeater equipment, the life requirement of the 100-milliwatt pump laser should also be no less than 25 years. In the past, products that could meet this technical indicator were mainly imported, and the main suppliers were Lumentum and II-VI in the United States. With the rapid development of my country's semiconductor pump laser research and development projects and application markets, the technology of pump lasers for optical communications in the hundreds of milliwatts has become increasingly mature. According to research, many domestic units have initially developed the ability to meet the requirements of high power and high reliability (Literature: Liu Jun, Li Bozhong, Chen Fang, et al. 400mW 980nm pump laser design [J]. Optical Communication Research, 2023(2): 63-68). However, there is currently no unified and standard life test method in China. In referring to similar life assessment methods, it is found that the assessment method is complex and time-consuming, which is not conducive to rapid assessment of product life in the research stage.

[0003] The standards that imported products are based on (Telcordia GR-468-CORE Generic reliability assurance requirements for optoelectronics devices used in telecommunication equipment and MIL-STD-883E Department of defense test method standard microcircuits) directly subject the laser module to an accelerated life aging test. This test requires a large number of test chambers that can meet specific packaging dimensions and power-on requirements, which is inconvenient to operate. This test requires a large number of products to be tested, which is time-consuming and costly.

[0004] A patent for "Lifetime assessment method and assessment system for high-power semiconductor laser beam combining module" (application number 202211680976.9, application publication date 2023.05.26) was issued in China. The acceleration factor is only temperature acceleration, the acceleration coefficient is relatively small, and the required test time is long.

[0005] Therefore, it is necessary to propose a test method that can more effectively and conveniently evaluate the life of pump lasers for submarine optical communications at the hundred-milliwatt level. Summary of the invention

[0006] 1. Technical issues to be resolved

[0007] The technical problem to be solved by the present invention is: how to propose a test method that can more effectively and conveniently evaluate the life of a pump laser for submarine optical communications at the hundred-milliwatt level.

[0008] (II) Technical solution

[0009] In order to solve the above technical problems, the present invention provides a test method for evaluating the life of a pump laser for submarine optical communication at the 100-milliwatt level. In this method, a plurality of groups of accelerated aging tests under different conditions are performed on the chip of the pump laser module to obtain the failure mechanism-related activation energy and current acceleration coefficient for estimating the chip life; wherein, the accelerated aging test is performed under acceleration conditions of a plurality of different currents and different temperatures; the failure of the pump laser is a temperature-dependent failure, and the failure rate is calculated using the Arrhenius relationship:

[0010]

[0011] Among them, λ0 is the failure rate under rated conditions, E a is the activation energy of the temperature accelerated failure mechanism, K B is the Boltzmann constant; T is the junction temperature of the chip, I is the current, and the subscripts ag and op represent the accelerated aging life test level and the rated operating level respectively;

[0012] In the accelerated life model, λ0, E a , m is a parameter, I op , K B , T op is a fixed constant, I ag 、T ag is the independent variable, λ is the dependent variable; five groups of independent variables I are obtained by using multiple groups of accelerated aging tests under different conditions. ag 、T ag and the dependent variable λ, and substitute them into equation (1) to obtain the system of equations. Through maximum likelihood estimation, we can obtain λ0 and E under a certain confidence level. a , m (confidence is usually ≥ 60%); activation energy E in the lifetime model of the pump laser modulea and m is approximately the activation energy E in the chip life model a and m, that is, the lifetime model of the pump laser module is:

[0013]

[0014] While conducting the multi-condition accelerated aging test on the chip, a group of accelerated aging life tests on the pump laser modules are also conducted simultaneously. In formula (3), λ is the failure rate under the accelerated life condition, χ is the confidence level, N is the total number of devices, and t i is the accelerated life test duration of the ith device; the current and temperature set in the accelerated aging life test of the pump laser module, as well as the failure rate obtained under the accelerated aging test conditions are substituted into formula (2) to obtain the failure rate of the pump laser module. Based on the failure rate of the pump laser module, it is determined whether the life of the pump laser module meets the index.

[0015] Preferably, if the failure rate is within 100 FIT, it is considered that the life of the pump laser module meets the 25-year indicator; if the failure rate is greater than 100 FIT, it is considered that the life of the pump laser module is less than the 25-year indicator.

[0016] Preferably, the chips are chips from different wafers.

[0017] Preferably, when setting different temperatures and currents to carry out accelerated aging tests on multiple groups of chips, when the current is 1.5A±0.05A, the temperatures are set to 95℃±5℃, 80℃±5℃, and 65℃±5℃, respectively; when the temperature is 80℃, the currents are set to 1.7A±0.05A, 1.5A±0.05A, and 1.3A±0.05A, respectively, for a total of 5 groups of tests.

[0018] Preferably, when carrying out the accelerated aging life test of a group of modules simultaneously, a group of packaged pump laser modules are selected and placed in an accelerated aging test box, the current is set to 1.5A±0.05A and the temperature is set to 95°C±5°C, and the failure of each module during the aging process is monitored.

[0019] The present invention also provides a system for implementing the method.

[0020] The invention also provides a method for using the system.

[0021] (III) Beneficial effects

[0022] The overall idea of ​​the present invention is that, because the chip is the weak link that restricts the life of the pump laser, the activation energy and current acceleration factor in the chip life model are approximately equal to the activation energy and current acceleration factor in the module life model, so that the accelerated aging life test of multiple groups of chips under different conditions is used to replace the accelerated aging test of multiple groups of modules, and the activation energy and current acceleration factor in the life model are obtained, which greatly reduces the difficulty and cost of the test. In addition, a method of simultaneously accelerating multiple conditions is adopted in the life model, such as temperature acceleration and current acceleration, and the number of samples is increased, and the test time can be reduced from 8000h to 5000h to 4000h to 2000h.

[0023] This test method can greatly save cost and time, and provide a way to more conveniently and quickly evaluate the life of products in the product pre-research and prototype stages. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The figure is a flow chart of a method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples.

[0026] The pump laser is mainly composed of a chip, a heat sink, a shell, a metal pin, an output pigtail, etc., among which the chip is the most important core component and is also the key to restricting the life of the pump laser. The present invention provides a test method for evaluating the life of a pump laser for submarine optical communication, which is to obtain a life model through a chip-level accelerated aging test. Compared with obtaining a life model through a module-level accelerated aging test, this method greatly reduces the difficulty in operation, does not require a large number of packaged modules, and greatly reduces the test cost; on the other hand, multiple accelerations are selected in the acceleration model to be performed simultaneously: temperature acceleration, current acceleration, etc. Compared with a single acceleration model of only temperature acceleration or current acceleration, the acceleration factor increases exponentially, greatly reducing the test time.

[0027] The present invention uses the chip to conduct multiple groups of accelerated aging tests under different conditions (high temperature, high current, etc.) to obtain the activation energy and current acceleration coefficient of the failure mechanism for estimating the chip life. The accelerated aging test should select multiple acceleration conditions of different currents and temperatures.

[0028] The failure of the pump laser is a temperature-dependent failure. The failure rate is calculated using the Arrhenius relationship:

[0029]

[0030] Among them, λ0 is the failure rate under rated conditions, E a is the activation energy of the temperature accelerated failure mechanism, KB is the Boltzmann constant (8.618*10-5eV / K); T is the junction temperature of the chip (unit: K), I is the current, P is the power, and the subscripts ag and op represent the accelerated aging life test level and the rated working level respectively.

[0031] In the accelerated life model, λ0, E a , m is a parameter, I op , K B , T op is a fixed constant, I ag , T ag The accelerated aging under different conditions can obtain 5 sets of independent variables (Iag, Tag) and dependent variables (λ), which are substituted into equation (1) to obtain the equation system. The maximum likelihood estimation fitting is used to obtain λ0 and E under a certain confidence level. a , m (confidence is usually taken as ≥60%). The chip is the weak link that restricts the life of the pump laser. The activation energy E in the module life model a and m is approximately the activation energy E in the chip life model a and m.

[0032] That is, the life model of the module is:

[0033]

[0034] While conducting the multi-condition accelerated aging test on the chip, a group of modules are also tested for accelerated aging life. In formula (3), λ is the failure rate under the accelerated life condition, χ is the confidence level (obtained from the table), N is the total number of devices, and t i is the accelerated life test duration of the ith device (in hours). Substituting the current and temperature set in the accelerated aging life test of the module and the failure rate obtained under the accelerated aging test conditions into formula (2), the failure rate of the module can be obtained.

[0035] According to actual needs, if the failure rate is within 100FIT, the module life is considered to meet 25 years. If the failure rate is greater than 100FIT, the module life is considered to be less than 25 years.

[0036] Please see attached Figure 1 The embodiment of the present invention provides a test method for evaluating the life of a pump laser for submarine optical communication at the 100-milliwatt level, which specifically includes the following steps:

[0037] Step 1: Provide the chips to be tested. If conditions permit, try to randomly select chips from different wafers to avoid test errors caused by clustering;

[0038] Step 2:

[0039] Step 2-1: Set different temperature, current and other conditions to carry out accelerated aging tests on multiple groups of chips. For example, when the current is 1.5A±0.05A, the temperature is set to 95℃±5℃, 80℃±5℃, and 65℃±5℃ respectively; when the temperature is 80℃, the current is set to 1.7A±0.05A, 1.5A±0.05A, and 1.3A±0.05A respectively, for a total of 5 groups of tests;

[0040] Step 2-2: Simultaneously conduct an accelerated aging life test on a group of modules. For example, select a group of packaged pump laser modules, place them in an accelerated aging test chamber, set the current to 1.5A±0.05A, and the temperature to 95℃±5℃, and monitor the failure of each module during the aging process;

[0041] Step 3: Obtain the activation energy and acceleration factor of the chip based on the accelerated aging test data of the chip. Accelerated aging under multiple conditions can obtain multiple sets of independent variables (Iag, Tag) and dependent variables (λ), which are substituted into equation (1) to obtain the equation system. Through maximum likelihood estimation fitting, λ0 and E under a certain confidence level are obtained. a , m (confidence level is usually ≥ 60%);

[0042] Step 4: Obtain the activation energy, acceleration factor, etc. of the chip according to the accelerated aging experiment data of the chip, that is, obtain the activation energy, acceleration factor, etc. of the module;

[0043] Step 5: Obtain the life model of the module;

[0044] Step 6: Substitute the accelerated aging life test conditions and test results of the module into the module life model, i.e., formulas (2) and (3), to obtain the failure rate of the module;

[0045] Step 7: Determine whether the failure rate of the module is within 100FIT. If the failure rate of the module is within 100FIT, execute step 8; if the failure rate of the module is not within 100FIT, execute step 9;

[0046] Step 8: Determine whether the module's service life meets the 25-year indicator;

[0047] Step 9: Determine that the module life does not meet the 25-year indicator.

[0048] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A test method for evaluating the life of a pump laser for submarine optical communication at the 100-milliwatt level, characterized in that: In this method, the chip of the pump laser module is used to conduct multiple groups of accelerated aging tests under different conditions to obtain the failure mechanism-related activation energy and current acceleration coefficient for estimating the chip life; wherein, the accelerated aging test is carried out under multiple acceleration conditions of different currents and different temperatures; the failure of the pump laser is a temperature-dependent failure, and the Arrhenius relationship is used to calculate the failure rate: Among them, λ0 is the failure rate under rated conditions, E a is the activation energy of the temperature accelerated failure mechanism, K B is the Boltzmann constant, m is the acceleration factor; T is the junction temperature of the chip, I is the current, and the subscripts ag and op represent the accelerated aging life test level and the rated working level respectively; In the accelerated life model, λ0, E a , m is a parameter, I op , K B , T op is a fixed constant, I ag , T ag is the independent variable, λ is the dependent variable; five groups of independent variables I are obtained by using multiple groups of accelerated aging tests under different conditions. ag , T ag and the dependent variable λ, and substitute them into equation (1) to obtain the system of equations. Through maximum likelihood estimation, we can obtain λ0 and E under a certain confidence level. a , m (confidence is usually taken as ≥ 60%); activation energy E in the lifetime model of the pump laser module a and m is approximately the activation energy E in the chip life model a and m, that is, the lifetime model of the pump laser module is: While conducting the multi-condition accelerated aging test on the chip, a group of accelerated aging life tests on the pump laser modules are also conducted simultaneously. In formula (3), λ is the failure rate under the accelerated life condition, χ is the confidence level, N is the total number of devices, and t i is the accelerated life test duration of the ith device; the current and temperature set in the accelerated aging life test of the pump laser module, as well as the failure rate obtained under the accelerated aging test conditions are substituted into formula (2) to obtain the failure rate of the pump laser module. Based on the failure rate of the pump laser module, it is determined whether the life of the pump laser module meets the index.

2. The method according to claim 1, characterized in that If the failure rate is within 100 FIT, it is considered that the life of the pump laser module meets the 25-year indicator; if the failure rate is greater than 100 FIT, it is considered that the life of the pump laser module is less than the 25-year indicator.

3. The method according to claim 1, characterized in that The chips are from different wafers.

4. The method according to claim 1, characterized in that When setting different temperatures and currents to carry out accelerated aging tests on multiple groups of chips, when the current was 1.5A±0.05A, the temperatures were set to 95℃±5℃, 80℃±5℃, and 65℃±5℃ respectively; when the temperature was 80℃, the currents were set to 1.7A±0.05A, 1.5A±0.05A, and 1.3A±0.05A respectively, for a total of 5 groups of tests.

5. The method according to claim 4, characterized in that When conducting accelerated aging life tests on a group of modules simultaneously, a group of packaged pump laser modules are selected and placed in an accelerated aging test chamber. The current is set to 1.5A±0.05A and the temperature is set to 95℃±5℃ to monitor the failure of each module during the aging process.

6. The method according to claim 1, characterized in that The pump laser includes a chip, a heat sink, a shell, a metal pin, and an output pigtail.

7. The method according to claim 1, characterized in that This method is applied in submarine optical communications.

8. A system for implementing the method as described in any one of strong claims 1 to 6.

9. The system according to claim 8, characterized in that The system is used in submarine optical communications.

10. A method of using the system according to claim 8.

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