Characteristics of metallic coated ultra-short semiconductor Fabry-Pérot lasers

Fabry-Pérot (F–P) lasers have attracted significant attention due to their extensive applications in optical communication and precision measurement fields. However, traditional F–P lasers are relatively large in size and face challenges in directly achieving single-mode lasing, which limits their applications. In this study, we employ a metallic coating layer to significantly enhance the light confinement of the F–P cavity, thereby substantially reducing the cavity length of the F–P laser. We have experimentally developed an F–P laser with a cavity length of approximately 6.8 μm, successfully achieving single-mode lasing at room temperature. The lasing mode exhibits an ultra-narrow linewidth of 0.06 nm and a relative high side-mode suppression ratio exceeding 30 dB, along with good linear polarization. Additionally, we propose a type of on-chip integrated laser based on metallic-coated F–P cavities, characterized by high coupling efficiency and large fabrication tolerances. Simulation results indicate that the coupling efficiency for double-ended and single-ended output waveguides reaches 79% and 55%, respectively. The metallic-coated ultra-short F–P lasers have great potential for applications in on-chip optical interconnects and photonic integrated chip systems.