Photonic molecule laser composed of GaInAsP microdisks

Abstract
We fabricated a photonic molecule consisting of GaInAsP microdisks, and obtained the lasing operation by photopumping. We also observed mode splits arising from the optical coupling, which was confirmed by an anticrossing characteristic against the disk diameter detuning and a miniband being dependent on the number of disks, their arrangement and coupling strength. The coupling characteristics were explained by considering bonding and antibonding states of modes, and by finite-difference time-domain calculation. Such a laser is expected to be some functional devices, and the concept of the photonic molecule will be helpful for the understanding of complex coupled modes.