Ultrafast GaN/AlN modulator based on quantum dot for terabit all-optical communication

An ultrafast all-optical modulator based on spherical quantum dot using electromagnetically induced transparency (EIT) technique in GaN/AlN structure, associated with inter-sublevel transitions, is proposed and analyzed. The aim of this paper is to modify and enhance the main parameters of an all-optical modulator such as, power consumption, modulation depth, maximum bit-rate and band-width. To realize these points, we have proposed a suitable quantum dot structure based on EIT in a strained GaN/AlN, with an internal barrier. Simulations show this barrier enhances the dot optical properties, such as dipole matrix element, linear susceptibility, and hence absorption coefficient, reducing the power consumption and increasing the modulation depth. Furthermore, using control signal in EIT process, carriers are driven from an upper state to a lower state from where they rapidly decay to the ground state increasing the modulation bit-rate and band-width.