Arbitrary phase modulation for optical spectral control and suppression of stimulated Brillouin scattering

Abstract

We investigate the use of external phase modulation to broaden the linewidth of a laser source. We use nonlinear optimization to find phase modulations that create nearly tophat-shaped discrete spectra and thus the highest total power within a limited linewidth and a limited peak spectral power density. Such phase modulations and spectra can be realized with an arbitrary waveform generator (AWG) and are attractive for suppressing stimulated Brillouin scattering in optical fiber. Compared to alternative modulation approaches, the AWG benefits from a large number of degrees of freedom and well-controlled spectral phase in the AWG output.