Analysis Of Thermal Characteristics Of Semiconductor Lasers

Semiconductor laser is an important device in optical communication system,its performance affects the transmission speed and distance of optical communication network.However,due to the temperature sensitivity of semiconductor materials,the performance and application of semiconductor lasers during operation will be affected by the internal thermal effect of devices.In this thesis,on the basis of thermal effect theory,a theoretical model of thermal effect of semiconductor lasers is established by using the finite element method(FEM).According to the thermal model,the temperature distribution of different structures of lasers is calculated and simulated.In this way,the heat dissipation structure of a new type of distributed feedback(DFB)lasers is optimized.At the same time,the structure of the arm phase region of the narrow linewidth thermally tuned multi-channel interference(MCI)lasers is designed and its linewidth will be measured.The main research contents of this thesis are:(1)The thermal characteristics of semiconductor lasers are studied in depth,the influence of temperature on the performance parameters of semiconductor lasers is analyzed,and the basic principle of heat transfer is introduced.Meanwhile,the finite element method and COMSOL software are briefly introduced.(2)Based on the COMSOL finite element analysis software,the theoretical thermal model of a new two-section DFB laser is established.The influence of several different heat dissipation structures on the temperature distribution is analyzed by using two-dimensional and three-dimensional models.The contents include: the influence of different top gold thickness on the heat dissipation efficiency of the laser;the influence of different substrate thickness on the temperature distribution of the core layer of the laser;the influence of different quantum well structures on the heat dissipation efficiency of the device;and the influence of different top thick gold structures on the heat transfer of the core layer.The heat dissipation scheme of the laser is optimized,and the progress of experiment is promoted.(3)The theoretical model of the narrow linewidth thermally tuned MCI laser is established by using the finite element method.The influence of the air insulation layer structure,the distance between the waveguides,the etching depth of the waveguides and the length of the microheater on the temperature distribution in the arm phase region are analyzed through the heat transfer module.The waveguide structures in the tunable region of the laser are determined according to the simulation results.Compared with the experimental results,the accuracy of the simulation results is verified.Finally,the structure of segmental support is designed to improve the stability of the suspended waveguide.(4)This thesis presents a linewidth measurement scheme for the narrow linewidth thermally tuned MCI lasers,the setup and related principles of the measurement system is introduced,and the accuracy of the system is verified.The linewidth of the thermally tuned MCI laser is measured by the measurement system,and compared with that of the electrically tuned MCI laser.