Impact of SiO₂ Current Blocking Layer on Optical Characteristics of GaN‐Based Microdisk Laser Diodes

The current blocking layer (CBL) technology plays a crucial role in the electrical injected GaN‐based microdisk laser diodes (LDs) because it effectively reduces the threshold current and mitigates self‐heating effect. Herein, the impact of SiO 2 CBL on the optical performance of blue microdisk LDs by finite‐difference time‐domain (FDTD) simulation method is researched on. Simulation results demonstrate that the optical power of microdisk LDs initially increases and then decreases with an increase of CBL size, due to alterations in the lateral and longitudinal optical filed distribution caused by changes in CBL size. However, the CBL with too large size also increases the diffraction loss. Therefore, the proposed design strategy of the CBL for microdisk LDs is that the dimensions shall be tuned to ensure perfect alignment between wave‐guided mode field distribution and the gain active region, while minimizing the radius of SiO 2 CBL.