双有源区结构4.7μm中波红外量子级联激光器

4.7μm mid-wave infrared quantum cascade laser with double active region structure

本文报道了一种基于双有源区的4.7μm中波红外量子级联激光器,脊宽为9.5μm,可实现室温连续基横模工作。通过在单有源区中心插入0.8μm InP间隔层,将原有的单有源区转变成双有源区结构,可显著降低器件有源区的峰值温度,同时抑制高阶横模的产生。在288 K温度下,腔长为5 mm的双有源区器件的阈值电流密度为1.14 kA/cm2,连续输出功率为0.71 W,快轴发散角为27.3°,慢轴发散角为18.1°。同采用常规单有源区结构器件相比,采用双有源区结构的器件,其最大光输出功率未出现退化,同时器件慢轴方向由多模变化为基横模,光束质量得到了显著改善。本工作为改善高功率中波量子级联激光器的慢轴光束质量提供了一种解决思路。

This paper reports a 4.7-μm mid-wave infrared quantum cascade laser based on double active region structure with a ridge width of 9.5μm,which can achieve continuous single transverse mode operation at room temperature.By inserting 0.8-μm InP,the original single active region is transformed into a double active region structure,which can significantly reduce the peak temperature of the device's active region and suppress the generation of higher-order transverse modes.At a temperature of 288 K,the device with a double active region structure with a cavity length of 5 mm has a threshold current density of 1.14 kA/cm^(2),a continuous output power of 0.706 W,a fast axis divergence angle of 27.3°,and a slow axis divergence angle of 18.1°.Compared with conventional devices with a single active region structure,the devices with a double active region structure have no degradation in their maximum optical output power and show a significant improvement in the beam quality in the slow axis direction of the device.These results provide a solution to the problem of the slow axis beam quality of high-power mid-wave quantum cascade lasers.