Comment on “Andronov bifurcation and excitability in semiconductor lasers with optical feedback”

Abstract
In a recent paper [M. Giudici et al., Phys. Rev. E 55, 6141 (1997)] a new explanation is proposed for the so-called low-frequency fluctuation phenomenon occurring in the emission of semiconductor lasers in an external cavity. We argue that the experimental results of the commented paper do not conflict with existing theory, which has been thoroughly tested with experiments, and that the claims made are rather speculative.