Injection-locked semiconductor lasers with delayed optoelectronic feedback

Optical injection and optoelectronic feedback are efficient techniques to externally control the spectral characteristics of a semiconductor laser. This paper presents theoretical and experimental results about the effects of a delayed optoelectronic feedback loop on the stability of an optically injected diode laser. In particular, negative feedback configurations (out-of-phase carrier reinjection) are shown to widen the injection-locking domain of the laser and reduce its unstable region. On the contrary, in positive feedback configurations (in-phase carrier reinjection), the laser diode generates a modulation with tunable multigigahertz frequency.