In this article, we report the demonstration of directly modulated grating-assisted microcylinder surface-emitting lasers (GAMSELs) with low threshold. Two second-order gratings are added onto the side and top of the microcylinder cavity to select a single mode with a radially polarized emission pattern and efficiently emit the mode vertically, respectively. Laser with cavity radius of 6.05 μm is demonstrated with continuous-wave lasing ranging from 1 °C to 50 °C. This radius is approaching the theoretically smallest radius for the microcylinder laser to work at O band. A low threshold of 3.6 mA at 15 °C is obtained for the GAMSEL laser. Single-mode lasing with side-mode suppression-ratio (SMSR) larger than 40 dB is also shown here. GAMSELs with different cavity radii are demonstrated as laser arrays. 3 dB direct modulation bandwidth of 12 and 14 GHz of GAMSELs with radius of about 8 and 10 μm are obtained, respectively. Besides, effects of the duty cycle of the top and side gratings, scattering losses of the cavity, gain peak of the epitaxial wafer and ion implantation are experimentally investigated.

中文翻译：

---

低阈值和直接调制光栅辅助微柱面发射激光器的演示

在本文中，我们报告了低阈值直接调制光栅辅助微柱面发射激光器 (GAMSEL) 的演示。两个二阶光栅被添加到微柱腔的侧面和顶部，以选择具有径向偏振发射模式的单模，并分别有效地垂直发射模式。腔半径为 6.05 μm 的激光器通过 1°C 至 50°C 的连续波激光进行演示。这个半径接近于微柱面激光器在 O 波段工作的理论上的最小半径。GAMSEL 激光器在 15°C 下获得了 3.6 mA 的低阈值。此处还显示了边模抑制比 (SMSR) 大于 40 dB 的单模激光。具有不同腔半径的 GAMSEL 被证明为激光阵列。分别获得了半径约为 8 和 10 微米的 GAMSEL 的 12 GHz 和 14 GHz 的 3 dB 直接调制带宽。此外，实验研究了顶部和侧面光栅的占空比、腔的散射损耗、外延片的增益峰值和离子注入的影响。