Asymmetrical response of semiconductor lasers in optical systems

The symmetry of the optical outputs of a semiconductor laser diode having the front and rear facets with equal reflectivity is destroyed by the injection of a reflected signal, even of weak intensity, from one side: this asymmetry must be taken into account when designing laser packages and integrated circuits. A systematic experimental investigation is presented. Moreover the behaviour of the system, i. e. the appearance of certain asymmetrical features together with the survival of the symmetry of other features, can be accounted for on the basis of a microscopic model, providing a link between the optical outputs from the two facets.