OPS-VECSEL芯片的生长与光谱研究

Growth and Spectral Analysis of OPS-VECSEL Chip

光泵浦半导体垂直外腔面发射激光器(OPS-VECSEL)是一种新型激光器,在很多领域都具有广阔的应用前景。采用MOCVD生长了工作波长为980nm的VECSEL芯片,测量了芯片X射线衍射(XRD)图谱,光致发光(PL)谱和反射谱,结果表明,芯片生长的准确性较高。同时采用物理光学的理论结合实际模型,运用矩阵分析方法计算了VECSEL的反射谱,计算结果与实验结果吻合良好。最后,通过对不同窗口层厚度的纵向增强因子的计算和分析得到了共振结构具有高的峰值增强,反共振结构具有大的增益带宽。在理论上提出,对于该OPS-VECSEL结构,采用共振和反共振结构之间的窗口厚度可以使其稳定工作在特定波长而又不严格限制增益带宽。

Optically pumped semiconductor vertical-external-cavity surface-emitting-laser （ OPS- VECSEL） is a novel semiconductor laser and can be applied in many fields potentially. A VECSEL chip with wavelength of 980 nm was grown by MOCVD. Results of XRD, photolumineseence （PL） and reflectivity of the chip show the accuracy of growth. Combining physical optics theory and the actual model, a matrix formulation method was used for numerical evaluation of VECSEL chip reflectivity. Theoretical analysis shows a good agreement with the experimental result. The longitudinal enhancement factor of VECSEL chips with different thickness of window layer was calculated. Calculation shows that the resonant structure has larger peak gain and the anti-resonant structure has wider gain bandwidth. It is proposed to choose an appropriate thickness of window layer to keep the laser operating stably at the designed wavelength, without unduly restricting the gain bandwidth.