在二极管激光阵列(DLA)光栅-外腔谱合成系统中, 由于DLA存在子单元光束发散角、 “smile”效应的位置偏差及指向性偏差等因素的综合作用, 将导致合成光束的光束质量降低。 综合考虑DLA子单元光束发散角、 “smile”效应等因素对谱合成系统中光束传输特性的影响, 建立了DLA光栅-外腔谱合成系统的光传输模型, 进而对谱合成系统中DLA子单元光束发散角、 “smile”效应的位置偏差及指向性偏差等因素对合成光束的光束质量影响进行了定量分析。 结果表明, DLA光源质量会明显影响合成光束的光束质量: DLA子单元光束发散角和“smile”效应引入的指向性偏差越大, 合成光束的光束质量就越差; “smile”效应引入的位置偏差在合束方向上对合成光束的光束质量没有影响, 而在非合束方向上引入的位置偏差将会明显降低合成光束的光束质量。 在实际工作应用中, 需要采取措施提高DLA光源质量, 以减小对合成光束的光束质量影响。

In Diode Laser Array (DLA) spectral beam combining (SBC) systems with grating-external cavity, the beam quality of the combined beam tends to degrade due to comprehensive function of factors involving divergence angle of light, positional deviation and direction angle deviation caused by “smile” effect of emitters, etc.. Based on the consideration of the effects of the divergence angle and “smile” effect of DLA emitters on the beam propagation characteristics, the light propagation model of DLA SBC systems with grating-external cavity has been built up, and the effects of divergence angle and the positional deviation and direction angle deviation caused by “smile” effect of DLA emitters on the beam quality of the combined beam in SBC systems have been analyzed quantitatively. The results indicate that, the beam quality of the combined beam would be significantly affected by the DLA light source quality, i.e., the bigger the divergence angle and the direction angle deviation caused by “smile” effect are, the worse the beam quality of the combined beam is. The positional deviation of emitters in beam-combination direction caused by “smile” effect has little impact on the beam quality of the combined beam, whereas the positional deviation in non beam-combination direction would significantly degrade the beam quality of the combined beam. In practical applications, measures should be taken to improve the DLA light source quality in order to eliminate the effect on the beam quality of the combined beam.