表面液晶-垂直腔面发射激光器阵列的热特性

液晶与垂直腔面发射半导体激光器(VCSELs)阵列结合可实现波长可调谐、偏振精确控制等,同时液晶的引入也会改变垂直腔面发射半导体激光器阵列的热特性,本文设计了表面液晶-垂直腔面发射激光器阵列结构,并开展了阵列的热特性实验研究.对比分析了向列相液晶层对VCSEL阵列热特性的影响,实验结果表明,1×1,2×2,3×3三种表面液晶-VCSEL阵列的阈值电流温度变化率最高可降低23.6%,热阻降低26.75%;同时,激光器阵列各发光单元之间的温度均匀性显著提高,出光孔与周围温差小于0.5℃.综上所述,VCSEL阵列中液晶层的引入不仅大大加速激光器阵列单元热量扩散,而且降低了有源区结温,提高了VCSELs激光器阵列热特性,为实现高光束质量的单偏振波长可控VCSEL激光器阵列打下了良好的理论和实验基础.

Thermal characteristics of surface liquid crystal vertical cavity surface emitting laser arrays

In recent years,with the increase of information processing capacity of optical networks and the continuous improvement of high-density optical communication technology,the requirements for the performance of light sources are also increased.High-quality VCSEL with beam polarization stability control plays an increasingly important role in the above fields.The combination of liquid crystal and vertical cavity surface emitting laser(VCSEL)array can realize wavelength tunability and precise polarization control.At the same time,the introduction of liquid crystal will also change the thermal characteristics of VCSEL array.In this paper,the structure of VCSEL array is designed and the experimental research on the thermal characteristics of VCSEL array is carried out.The effects of nematic liquid crystal layer on the thermal characteristics of VCSEL array are compared and analyzed.The experimental results show that the threshold current temperature change rate of 1×1,2×2 and 3×3 surface liquid crystal VCSEL array can be reduced by 23.6%and the thermal resistance can be reduced by 26.75%.Moreover,the saturated optical power of VCSEL array can be improved to a different degree.Meanwhile,the liquid crystal layer can effectively increase the heat transverse conduction and reduce the optical hole.The temperature difference between the light outlet and the table makes the heat conduction time very short at a small distance between the light outlet and the table,which is more conducive to the uniform temperature distribution of the laser array.The experimental results show that the temperature difference between the light outlet and the surrounding is less than 0.5℃.To sum up,the introduction of liquid crystal layer into VCSEL array not only greatly accelerates the thermal diffusion of laser array unit,but also reduces the junction temperature of active region,improves the thermal characteristics of VCSELs laser array,and lays a good theoretical and experimental foundation for realizing the high beam quality single polarization wavelength controllable VCSEL laser array.