Investigation of the dynamical behaviour of a high-power laser diode subject to stimulated Brillouin scattering optical feedback

In this work, we propose a new scheme of optical feedback using stimulated Brillouin scattering (SBS). A high-power laser diode emitting at 1450 nm stimulates Brillouin back-scattering in a 4km-long optical fibre and the back-scattered light is injected back into the laser diode for optical feedback. The experimental results with RF spectrum exhibit clearly the Brillouin frequency shift at 11.46 GHz. Although the frequency shift is very large, the laser diode subject to optical feedback using SBS shows abundant dynamics. RF spectrum maps are also established with respect to the laser drive current. The results are compared with the ones for conventional optical feedback and it is clearly shown that the dynamical behaviours for both the configurations are very different. The investigation with autocorrelation functions reveals that the time-delay signature vanishes completely using the SBS feedback scheme unlike the conventional feedback one.