传导冷却半导体激光阵列温度均匀化研究

Study on temperature uniformity of conduction cooled semiconductor laser array

高功率半导体激光器阵列已经广泛应用于许多领域。Smile效应是由高功率半导体激光器阵列(巴条)本身在封装过程中与热沉之间热膨胀系数(CTE)失配导致的热应力造成的。各个发光点在横向上不在一条直线上,从而导致半导体激光阵列整体发光弯曲。较大的Smile值可以引起光束质量降低、造成光束耦合和光束整形困难。为了降低热串扰实现巴条温度均匀化,我们在传统CS热沉的基础上,引入高热导率铜基石墨烯(GCF)与孔状结构,对CS被动式制冷半导体巴条热应力分布不均导致的Smile效应进行了数值模拟与仿真分析。在热功率为60 W的条件下,一方面,当仅有GCF材料,并且其长度为8 mm时,温差从最初的7.94℃降低到3.65℃;另一方面,在合理的温升范围内,当GCF的长度为8 mm时,结合增加热沉热阻的孔状结构时,温差进一步降低到3.18℃。

High power semiconductor laser arrays （bars） have been widely used in many fields. Thermal stress induced by mismatch of thermal expansion coefficients between the bar and heat sink leads to smile effect. Larger smile can induce a lower beam quality which causes difficulty in collimation of laser beam. Thermal uniformity of the bar can be achieved by reducing temperature of the intermediate light emitting unit caused hy thermal crosstalk. This paper presents the optimization of heat sink structure for temperature uniformity of the bar. Graphene on copper foil （GCF） with high thermal conductivity and two symmetrical holes （each beside an end of the foil） are adopted to optimize the traditional conduction cooled semiconductor （CS） heat sink. Numerical simulations on the thermal behavior of the CS-packaged bar show that, when the GCF foil is 8 mm long, the temperature difference is reduced from 7.94 ℃ to 3.65 ℃ ; the through holes cause temperature rise of emitters on both sides of the bar, and the temperature difference is further reduced to 3.18 ℃.