基于载流子注入产热机制的半导体激光器热模型分析

为解决常用经验计算公式参数复杂、产热项考虑不足等问题,采用优化的激光器热模型分析了激光器连续工作时有源区温度的变化并进行了实验验证。通过分析有源区注入载流子产热机制,建立了替代传统的热源计算公式的经验计算公式,考虑了载流子通过激光器内部渐变异质结时的势垒电阻以提高焦耳热计算精度。制作了电极尺寸为10μm、台面尺寸为20μm的半导体激光器件并对器件热特性进行了模拟。由于未考虑热载流子注入效应,利用传统经验公式得出的有源区热功率密度比提出的优化模型偏低,因而理论模拟的器件内部温升也偏低。对激光器出光特性进行测试,推导出不同注入电流下激光器内部有源区的温升。测量与理论分析对比表明,采用经验公式得出的结果比实际测试结果偏低,而优化的热模型解决了该问题,利用该方法得出的有源区温升与测试结果最大偏差仅为0.2K,且温升随注入电流的变化趋势一致。

Analysis of the Thermal Model Based on the Carrier Injection Mechanisms within the Semiconductor Laser

In order to solve the problems existed in the calculation of self heating in the active layer of semiconductor lasers, a new model for simulating the self-heating is introduced. The heat source induced by the carrier injection is analyzed. And the method for calculating the conductance of hetero-junction is also investigated to improve the precision of calculated joule heat. Edge emitting laser is fabricated, and the width of P-contact and stripe of fabricated laser are 10 μm and 20 μm, respectively. From the simulation result, the heat source density deduced from the traditional experience model is much lower than that from the optimized thermal model suggested. Thus a lower temperature rising is proposed in the experience model. By testing the shift of the lasing characteristics at different injected currents, the temperature of active layer is gained. Finally, the change of temperature with injected current obtained from simulation and testing is compared. The temperature rising gained from the experience model is lower than that of the experimental one. However, the new optimized model solves this problem. As a result of the optimized model, the maximum deviation between simulated temperature rising and tested one is about 0.2 K when the injected current is above the threshold current.