Non-sinusoidal phase modulations for improved performance of high power lasers

Spectral broadening is required on high power lasers to avoid Stimulated Brillouin Scattering in the laser chains and to smooth the focal spot. Up to now, spectral broadening has been obtained by sinusoidal phase modulations. However, it leads to non-homogeneous spectra, which is not optimal. In this paper we show that, thanks to non-sinusoidal phase modulations, performance of high power lasers may be enhanced. Furthermore, we demonstrate theoretically and experimentally that adjusting non-sinusoidal phase modulations may be almost as simple as adjusting sinusoidal ones.