900nm三叠层隧道级联激光器的结构优化研究

采用金属有机化合物气相淀积方法生长了900nm的三叠层隧道级联激光器。针对隧道级联激光器存在工作电压高、材料各层的光场耦合等问题,分别采用δ掺杂、扩展波导等技术对激光器结构进行了优化,并通过模拟计算对隧道结耗尽区宽度进行了优化。通过优化隧道结δ掺杂的生长条件,得到n+GaAs的掺杂浓度大于1×1019/cm3,使工作电压下降1V;通过采用扩展波导,使垂直发散角由常规结构的35°减小到20°。将900nm的三叠层隧道级联激光器制作成条宽300μm、腔长800μm的条形激光器,采用同轴封装形式,在20A的脉冲工作电流下,输出功率达到55W,斜率效率达到2.9W/A,以上指标是普通激光器的3倍。

Study on Structural Optimization of 900 nm Triple Stacks Tunnel Cascade Lasers

The 900 nm triple stacks tunnel cascade laser was grown by metal organic chemical vapor deposition(MOCVD).Based on the problems of high operating voltage and optical field coupling of each layer for tunnel cascade lasers,the laser structure was optimized by the δ-doping technique and expanding waveguide,and the tunnel junction depletion region width was also optimized by analog computation.The doping concentration of n+GaAs was more than 1×1019/cm3 by the optimal δ-doping growth condition of the tunnel junction,through which the operating voltage was reduced 1 V.The vertical far-field width at half-maximum was reduced from 35°to 20°by using the expanding waveguide.The strip laser with 300 μm strip width and 800 μm cavity length in coaxial encapsulation form was fabricated with the 900 nm triple stacks tunnel cascade laser.The output power and slope efficiency reach 55 W and 2.9 W/A at 20 A pulse current,respectively,which are three times that of conventional lasers.