Analysis of frequency chirping of semiconductor lasers in the presence of optical feedback

The frequency chirping of a single-mode semiconductor laser in the presence of optical feedback is studied by rate-equation analysis. The model includes the amplitude-phase-coupling and spectral-hole-burning effects. A simple analytical formula is obtained in the small-signal regime that shows that the amplitude-phase-coupling effect also enhances the chirp-reduction ratio and that the maximum reduction of frequency chirping can be achieved at the same time as maximum line narrowing in the in-phase condition.