Mode synchronization in a laser with coupled disk cavities

Lasers operating on whispering gallery modes (WGMs) and emitting in the mid-IR wavelength range (2.2–2.4 $\mu$m) have been created on the basis of coupled semiconductor disk cavities with half-ring contacts. It is established that a separate connection of half-ring contacts of the WGM laser corresponds to a multimode character of radiation, while the connection of all (four) contacts leads to lasing in a single-mode regime. Possible mechanisms of mode synchronization in the proposed WGM lasers are discussed.