Synchronization of bandwidth-enhanced chaos in semiconductor lasers with optical feedback and injection

We experimentally investigate the generation and synchronization of bandwidth-enhanced chaos in a semiconductor laser (drive laser) that is subject to optical injection from another chaotic semiconductor laser (injection laser) with optical feedback. Effective bandwidth enhancement is achieved over 12 GHz, under the condition in which the optical wavelength of the drive laser is positively detuned with respect to that of the injection laser, outside the injection locking range. The bandwidth-enhanced chaotic signal of the drive laser is injected into a third semiconductor laser (response laser) for synchronization. Synchronization of chaos with a bandwidth greater than 12 GHz is observed between the drive and response lasers, under the condition in which the optical wavelength of the response laser is negatively detuned with respect to that of the drive laser, satisfying the injection locking condition. High-quality chaos synchronization is observed within the injection locking range between the drive and response lasers and under the condition of a low relaxation oscillation frequency of the response laser.