Dual-Mode Microcavity Semiconductor Lasers

Dual-mode microcavity semiconductor lasers are investigated for potential applications in photonic microwave and optical frequency comb (OFC) generation. By regulating whispering-gallery modes (WGMs) in square microcavities, dual-mode lasing is achieved with frequency intervals ranging from tens to hundreds of gigahertz. In the square microcavities, the fundamental and first-order transverse WGMs have spatially separated field distributions, which allow stable dual-transverse-mode lasing with mode intervals inversely proportional to the cavity areas. Dual-transverse-mode square microcavity lasers are experimentally demonstrated with frequency intervals ranging from similar to 35 to similar to 150 GHz. Photonic microwaves and OFCs are successfully generated based on the dual-mode square microcavity lasers. To enhance the transverse-mode intervals, circular-side square microcavity lasers with a square hole in the center are proposed and demonstrated, and dual-transverse-mode lasing with a frequency interval up to similar to 0.56 THz is obtained. Furthermore, a square-fabry-Perot coupled-cavity microlaser is demonstrated to increase the output power and introduce an additional degree for manipulating the lasing modes. Dual-mode lasing is realized with a frequency interval of similar to 0.5 THz, a single mode optical fiber coupled power of similar to 3 mW, and a wavelength tuning range of similar to 10 nm.