Abstract

The low facet reflectivity makes a diode laser very sensitive to external influences such as, e.g. weak feedback from a distant mirror. This sensitivity can succesfully be used in stabilization and line-narrowing schemes based on delayed external optical feedback (see refs. 1–8 in [1]). Recently, succesful frequency control of an AlGaAs diode laser using resonant phase- conjugate reflection was reported by Cyr et al.[2]. This experiment shows the possibility of locking the laser frequency through external optical feedback by the phase-conjugate reflection. A theory of phase-conjugate feedback in a semiconductor laser has been given by Agrawal and Klaus [1], but they formulated the problem for the case of a self-pumped mirror only. Therefore, in their theory the externally reflected signal does not provide a reference frequency to which the laser can lock.

© 1992 Optical Society of America