The Thermal Characteristics Of Semiconductor Lasers And Packaging Technology

Study on the thermal characteristics and packaging technology of semiconductor lasers has been presented in this dissertation. The heat elimination of semiconductor lasers with different type of structures and materials have been researched theoretically and experimentally in detail, the works have been focused on 1.3 μ m ridge waveguide InAsP/InGaAsP MQW lasers as well as 8 μ m InAlAs/InGaAs/InP mid-infrared quantum cascade lasers. Main works are summarized as following:1. A simulation method, which is based on commercially available finite-element analysis software, has been developed for the thermal analysis of semiconductor lasers. By using this method, the temperature distribution as well as thermal resistances of the 1. 3μ,m ridge waveguide InAsP/InGaAsP MQW lasers and the 8μm InAlAs/InGaAs/InP mid-infrared quantum cascade lasers with substrate-side or epilayer-side mounting forms have been obtained. Results show that the epilayer-side mounting form can reduce the heat accumulation in the lasers more effectively.The transient thermal characteristics of the lasers operated in pulse driving conditions are simulated for the first time; results show that at pulse driving condition, the apparent thermal resistance of the device is pulse parameter dependent, especially at lower duty cycle. The thermal analysis of ridge waveguide InAsP/InGaAsP MQW lasers with different cavity length, ridge width, solder thickness and solder thermal conductivity also have been simulated and the results are discussed.2. A laser chip package technique including solder coating and chip mounting processes has been developed based on our laboratory facilities,for this purpose a mounting bench have been designed and fabricated. By using this mounting bench in conjunction with optimized process, the laser chips have been mounted on Au coated Cu heat sinks effectively for further thermal analysis.3. The ridge waveguide InAsP/InGaAsP MQW lasers have been characterized by using pulse I-P and I-V methods. The I-P measurements show that, laser chips mounted on heat sink assuredly give out more light power than un-mounted chips, from the I-V measurements, the thermal resistances of the laser chips also have been deduced, which all confirmed the validity of our mounting process. The results have been discussed.