Heat Dissipation Characteristics Of A Coaxial Packaged LD With A Built-in TEC Temperature Control Function

Semiconductor laser diode (LD), as a new light source and with advantages of small size, light weight, high photoelectric conversion efficiency, direct modulation and low cost, is widely used in areas of laser printing, precision measurement, automatic control, optical communication, medical equipment, military etc. However, LD is a temperature-sensitive component. Chip heat density is dramatically increased with highly integrated electronic components, and thus the heat problem has become one of the key issues affecting the stability and service life of LD. Therefore, the analysis of heat dissipation characteristics of LD and its temperature control has gradually become significant.Coaxial packaged LD is a core device in optical communication network whose temperature stability directly affects the speed and bandwidth of the network. With the development of thermoelectric cooling technology, miniature thermoelectric coolers (TEC) were able to be packaged into the interior of LD, thereby becoming the best choice for temperature control. In this thesis, we analyzed and simulated the heat dissipation characteristics of coaxial packaged LD with built-in TEC temperature control function.The 3D model realistically reflecting the thermal characteristics of a coaxial packaged LD was established by using SolidWorks. Then we carried out thermal simulation analysis of the actual model of above-mentioned LD through FloEFD software, and presented a simplified equivalent model of LD in order to improve simulation speed.The steady-state and transient thermal analysis of coaxial packaged LD models were analyzed in this thesis. In steady-state thermal analysis, temperature distribution of coaxial packaged LD was simulated while the TEC does not work in the state; Meanwhile, the temperature variations of LD and thermistor were calculated at different initial temperatures; The working state of the TEC was explained by the working principle of TEC. In the transient thermal analysis, the changes of temperature characteristics over time was simulated when the TEC was in inoperative state, and the comparison of simulation results with results in steady-state was also carried out. When TEC was under normal operating condition, the temperature distribution of coaxial packaged LD model with actual working condition was analyzed by adding an external heat sink. Meanwhile, the cooling capacity and the scope of optimal operating current of TEC were all studied in this work.The paper conducted the grid optimization for the coaxial packaged LD model based on FloEFD, therefore speeding up the simulation efficiency. In the meantime, the size and structure were also optimized in internal components. Finally, a TEC temperature control system was built through STM32 and temperature controlling characteristics of the TEC was experimentally tested.