氧化孔形状对光子晶体垂直腔面发射激光器模式的影响

Study on influence of oxide aperture shape on modal characteristics of VCSELs

用时域有限差分方法对氧化孔限制型外腔式光子晶体垂直腔面发射激光器(VCSEL)在小氧化孔下氧化孔形状对激光器模式特性的影响进行了模拟计算.建立了三维光子晶体面发射激光器光场计算模型,分析了氧化孔形状变化对器件远场特性与频率特性的影响.研究发现,氧化孔形状可影响光子晶体VCSEL的模式特性,尤其是频谱特性.从模场分布的角度可解释为菱形氧化孔的对称性与高阶模的不一致.但随着光子晶体刻蚀深度的增加和氧化孔的增大,这种影响逐渐减小,分析解释了其原因.研究结果为提高光子晶体面发射激光器的性能提供了参考.

The effects of oxide aperture shape whose size is small, on the mode characteristics of external cavity oxide-confined photonic crystal vertical cavity surface emitting laser （VCSEL） is studied extensively based on the finite-difference time-domain algorithm. A new three-dimensional model of optical field in photonic crystal VCSEL is built and the influence of the variation in aperture shape on the characteristics of far-field and spectrum is pointed out. It is found that the modal characteristics of PhC-VCSEL are influenced by the shape of oxide aperture, the influence on spectrum feature is more apparent. It can be explained from the distribution of modal field by the fact that the symmetrical characteristic of prismatic oxide aperture is not identical to that of high-order mode. But the influence is less apparent while the depth of photonic crystal hole is deeper. The reason for this matter is illustrated. The results can be used to guide the fabrication of external cavity oxide-confined photonic crystal VCSELs.