Analysis And Optimization Of Thermal Characteristics And Thermal Stress Of Tunable Semiconductor Laser Package

Semiconductor lasers have a wide range of applications in industry,medicine,aerospace,radar,measurement and detection,etc.However,semiconductor lasers still have many problems and challenges.The electro-optical conversion efficiency of the semiconductor laser is about 70%,and a large amount of heat is generated during operation,which causes the temperature of the semiconductor laser chip to rise.The increase in the temperature of the semiconductor laser will cause its center wavelength to shift,broaden the spectrum width,decrease the output power and decrease the reliability and other problems.In addition,due to the mismatch of the thermal expansion coefficient of the laser chip,the solder,and the heat sink,there is a large thermal stress inside the semiconductor laser,which leads to a series of problems such as warping,cracking of the bonding layer,and fatigue fracture of the semiconductor laser chip.In order to improve the heat dissipation performance of the semiconductor laser,improve its thermal management,achieve high thermal stability of the semiconductor laser,and improve the reliability of the semiconductor laser.This paper studies the influence of different package structure,material types and other parameters on the heat dissipation performance of tunable semiconductor lasers,and systematically analyzes the thermal characteristics and thermal stress of tunable semiconductor lasers under different conditions.Reveal the internal relationship between different parameters and the thermal performance of tunable semiconductor lasers,determine the key parameters that affect the thermal performance of tunable semiconductor lasers,optimize the key parameters through orthogonal experiments,and achieve the optimization of heat dissipation and mechanical performance of tunable semiconductor lasers.The main research work and research results are as follows:(1)Based on the package structure of the tunable semiconductor laser,the package structure of the tunable semiconductor laser is simplified and a numerical simulation model is established;the temperature characteristics of the tunable semiconductor laser are summarized and analyzed.Based on the simulation model of tunable semiconductor laser,the influence of thermoelectric cooler(TEC),ambient temperature,heat generation power and other parameters on the thermal performance of tunable semiconductor laser.The study found that the TEC temperature control module can significantly reduce the junction temperature of the tunable semiconductor laser;and when the ambient temperature is between-5°C and +75°C,the tunable semiconductor laser can remain stable.In addition,the heat consumption of the tunable semiconductor laser has a great influence on temperature control.By reducing the heat consumption of the tunable semiconductor laser,the high stability of the performance of the tunable semiconductor laser can be realized.(2)Establish the residual thermal stress analysis model of the tunable semiconductor laser,and in-depth research and analysis of the residual thermal stress generation mechanism inside the semiconductor laser package structure.In order to optimize the heat dissipation path of the semiconductor laser,the application performance of nano-silver solder,“In”solder and Au Sn solder in the semiconductor laser are studied in this paper.The research results show that Au Sn solder has the largest thermal stress and warpage deformation,but it can achieve the integrity of the patch;nano-silver solder paste can achieve a lower semiconductor laser LD junction temperature,especially for higher power tunable semiconductor lasers;“In” solder can obtain lower thermal stress and warpage of the tunable semiconductor laser.In addition,nano-silver solder paste has great application potential in tunable semiconductor lasers,and the sintering process has a great influence on its performance.This article analyzes and studies the application performance of different nanosilver sintering processes in tunable semiconductor lasers.The research results show that different auxiliary pressures have a greater impact on the performance of nano-silver solder paste in tunable semiconductor lasers;When the auxiliary pressure is in the range of 1 to 40 MPa,the residual thermal stress of the tunable semiconductor laser first decreases and then increases.When the auxiliary pressure is 10 MPa,the maximum residual stress of the tunable semiconductor laser reaches the minimum value,and its minimum value is 14.60 MPa.In addition,as the auxiliary pressure increases,its warpage deformation also increases.(3)Based on the tunable semiconductor laser numerical simulation model,explore the relationship between different structures and solder selection and the thermal characteristics of the tunable semiconductor laser;The effects of three solder types,different solder thicknesses,and different heat sink sizes on the junction temperature of the tunable semiconductor laser LD(Laser Diode)are studied separately,and the key parameters are extracted and optimized to obtain the best tunable semiconductor laser structure design parameters.The research results show that the junction temperature of the tunable semiconductor laser LD packaged with nano silver solder paste is the lowest,which is 0.26?lower than the LD junction temperature of the Au Sn solder package.Especially for the slightly higher power semiconductor laser,the heat dissipation effect of the nano silver solder paste is more obvious;The thinner the solder thickness,the lower the junction temperature of the LD;The length of the heat sink has almost no effect on the junction temperature of the tunable semiconductor laser LD,and the width of the heat sink has the greatest effect.In this paper,the best tunable semiconductor laser structure parameters are obtained.Compared with the existing tunable semiconductor laser packaging structure,the junction temperature of the tunable semiconductor laser is reduced by 5.2%,and the specific temperature is 26.23?.Based on the optimal design of the tunable semiconductor laser packaging structure,high thermal stability during the operation of the tunable semiconductor laser can be achieved.