Dynamical Characteristics of a Dual-Beam Optically Injected Semiconductor Laser

Dual-beam optically injected semiconductor lasers have been utilized in the field of microwave photonics for generations of microwave signals. To better understand the nonlinear behavior of a dual-beam optically injected semiconductor laser, we experimentally investigate the dynamics scenarios and their transition routes. By injecting a slave laser with beams from two master lasers, mappings of the dynamics scenarios including PP, PS, SP, SS, S´ S´, S´ L, LS´, and LL are plotted under different injection strengths and detuning frequencies. These scenarios are defined and differentiated by whether the dynamics and the characteristic frequencies originated from the single-beam injection scheme are being preserved (P), shifted (S), or suppressed (S^´) after both beams are simultaneously injected. The letter L is used if the slave laser is already injection-locked by one of the beams under the single-beam injection condition. The transition routes among these dynamics scenarios are shown to be clearly traceable by tracking and comparing the oscillation frequencies of the slave laser under the dual-beam and single-beam injections. Moreover, frequency-locking states are observed experimentally the first time in a dual-beam optically injected semiconductor laser, which occur when the frequency pushing effects from the two injected beams with opposite detunings balance each other off.