All-optical noninvasive control of unstable steady states in a
semiconductor laser ¨ ¨
All-optical noninvasive control of a multi-section semiconductor laser by means of time-delayed feedback from an external Fabry-Perot cavity is realized experimentally. A theoretical analysis, both in a generic model as well as a device-speciﬁc simulation, points out the role of the optical phase. Using phase-dependent feedback we demonstrate stabilization of the continuous-wave laser output and noninvasive suppression of intensity pulsations.