大功率半导体激光器阵列热串扰行为

Thermal crosstalk of high-power diode laser array

以硬焊料传导制冷,30%填充因子半导体激光器阵列为例,建立了三维有限元模型,对阵列内部各发光单元之间的热串扰行为进行了分析研究。结果表明,当其连续波工作时间大于1.2 ms后,阵列内发光单元之间出现热串扰现象;当次热沉由CuW合金改为铜金刚石复合材料时,阵列内发光单元自热阻和相邻发光单元的串扰热阻降低,有效地降低了各发光单元之间的热串扰行为。保持阵列宽度、发光单元数目及发光单元周期不变,发现随阵列填充因子的增加,器件热阻以指数衰减趋势逐渐降低,而发光单元间的热串扰特性对此变化并不敏感;保持阵列单个发光单元输出功率,发光单元尺寸及阵列宽度不变,增加发光单元个数后,阵列内各发光单元之间热串扰加剧,填充因子越高阵列升温速率越快;但在最初约70μs内,包含不同数目发光单元的阵列最高温度差异仅约0.5℃,有利于多发光单元高填充因子器件高功率输出。

A three-dimensional thermal model is established for a hard solder packaged, conduction-cooled diode laser array, which contains 19 emitters, its fill factor is 30%, and the width of emitting area is 150 tam. The thermal crosstalk among emit ters in the diode laser array has been studied systematically. It is found that there is an obvious thermal crosstalk among the emit ters in the diode laser array after the device is operated for more than 1.2 ms in continuous wave mode. While the sub-mount ma terial changes from copper-tungsten alloy to copper-diamond composites, the thermal resistance of each emitter and the interactive thermal resistance among adjacent emitters in the diode laser array decrease obviously. It is shown that this package structure de sign can reduce the thermal crosstalk behavior of the emitters effectively. The effect of the emitter size and pitch on the thermal characteristics of device is analyzed while the output power of the device, the number of the emitters, the cycle of the emitters and the width of the diode laser array are kept constant. The results show that both the thermal resistance of device and the thermal resistance of each emitter decrease exponentially with the increasing of the fill factor of the diode laser array, but the thermal crosstalk characteristics among emitters are not sensitive to the emitter size and pitch. On the other hand, keeping the output power of each single emitter, the emitter size and pitch, and the width of diode laser array constant, the thermal crosstalk behav- ior of the emitters is heavily influenced by the number of the emitters in diode laser array. Specifically, the higher the fill factor is, the more quickly the temperature of diode laser array rises. But during the first 70 tas, the highest temperature difference a mong these devices containing different number of emitters is about 0.5 ℃ ,it is benefited to the high-power output of device hav ing high fill factor in this period. This research is significant to the design of the structure of diode laser array, especially to the optimization of the fill factor, the emitter size and pitch of diode laser arrays. More importantly, it also presents necessary refer ences for the package structure design of diode laser array.