Photonic-Molecule Single-Mode Laser

We report in this letter the fabrication of edge-alignment-coupled whispering gallery mode photonic-molecule microdisk by femtosecond laser direct writing of dye-doped resins, which results in single-mode lasing output. Under picosecond laser pumping, the excited energy is distributed at the disk periphery and the coupling happens at the overlapping edge of two disks. As a result of mode coupling through Vernier effect, single-mode lasing is achieved in two-microdisk and three-microdisk coupled lasers of various sizes. The effect in the coupled system is confirmed by numerical simulation. This letter may open up a new avenue to the 3-D integrated optoelectronics.