Huang Wei-Hao, Shan Chi-Yao, Chi Kai-Lun, Xu Yi-Jun, Lu Tien-Chang
Department of Photonics, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan.
Department of Opto-Electronic Development Center, WIN Semiconductor Corporation, Taoyuan, Taiwan.
Sci Rep. 2025 Sep 1;15(1):32037. doi: 10.1038/s41598-025-17744-1.
This paper characterizes the performance of 940 nm single-junction (1 J) and triple-junction (3 J) vertical-cavity surface-emitting laser (VCSEL) arrays, tested at room temperature under 1.8 ns pulsed current injection. By suppressing thermal effects, the slope efficiency (SE) of the 1 J VCSEL array reaches 1.05 W/A, while the 3 J VCSEL array achieves 3.2 W/A, with a peak output power exceeding 120 W, demonstrating a significant performance enhancement. Furthermore, we observe that in the 3 J VCSEL array, the far-field (FF) divergence angle gradually decreases with increasing injection current, reducing from approximately 17° to about 5°. The far-field beam profile exhibits a Gaussian distribution, and spectral measurements indicate that the fundamental mode is dominant. We further analyze the characteristics of the VCSEL through both simulations and measurements. Current path analysis reveals that in the 3 J structure, the presence of a highly doped tunnel junction (TJ) and multiple oxide layers alleviates current crowding compared to the 1 J structure, resulting in a different gain distribution. Calculations show that the overlap between the gain region and the fundamental mode is greater than that of higher-order modes, which may explain the dominance of the fundamental mode. The results from single-device testing align with the observations in the VCSEL array, consistently demonstrating fundamental mode dominance. This phenomenon contributes to a reduced divergence angle, presenting a significant advantage for future optoelectronic applications.
本文描述了940纳米单结（1J）和三结（3J）垂直腔面发射激光器（VCSEL）阵列的性能，这些阵列在室温下通过1.8纳秒脉冲电流注入进行测试。通过抑制热效应，1J VCSEL阵列的斜率效率（SE）达到1.05瓦/安，而3J VCSEL阵列达到3.2瓦/安，峰值输出功率超过120瓦，显示出显著的性能提升。此外，我们观察到在3J VCSEL阵列中，远场（FF）发散角随着注入电流的增加而逐渐减小，从大约17°减小到约5°。远场光束轮廓呈现高斯分布，光谱测量表明基模占主导。我们通过模拟和测量进一步分析了VCSEL的特性。电流路径分析表明，在3J结构中，与1J结构相比，高掺杂隧道结（TJ）和多个氧化层的存在减轻了电流拥挤，导致增益分布不同。计算表明，增益区域与基模之间的重叠大于高阶模，这可能解释了基模的主导地位。单器件测试结果与VCSEL阵列中的观察结果一致，始终表明基模占主导。这种现象有助于减小发散角，为未来的光电子应用带来显著优势。
