A method for stimulated Brillouin scattering suppression in an optical transmission system, the method comprising: receiving a radio frequency, RF, information-carrying signal; applying one or more dithering signals to a first frequency signal having a first frequency that is at least twice the highest frequency of the radio frequency, RF, information-carrying signal, to generate a dithered high frequency signal having a frequency higher than that of the RF information-carrying signal; splitting the dithered high frequency signal, such that a first portion of the dithered high frequency signal is for directly modulating a light source and a second portion of the dithered high frequency signal is for adjustment by an amplitude and phase adjustment circuit; emitting a light beam from the light source while directly modulating said light source with the first portion of the dithered high frequency signal; externally intensity modulating the light beam emitted from the light source with a phase-adjusted second portion of the dithered high frequency signal in a manner that minimizes the intensity modulation caused by modulation with the first portion of the dithered high frequency signal so as to recover a symmetry of an optical spectrum of the modulated light beam, wherein the frequency of the adjusted second portion of the dithered high frequency signal is at least twice the frequency of the RF information-carrying signal; wherein the RF information-carrying signal and the phase-adjusted second portion of the dithered high frequency signal are pre-distorted by a signal calculated to reduce beat products of the dither tone with higher-order distortions of the RF-information-carrying signal; and coupling into the optical fiber the light beam modulated with the RF information-carrying signal. receiving a radio frequency, RF, information-carrying signal; applying one or more dithering signals to a first frequency signal having a first frequency that is at least twice the highest frequency of the radio frequency, RF, information-carrying signal, to generate a dithered high frequency signal having a frequency higher than that of the RF information-carrying signal; splitting the dithered high frequency signal, such that a first portion of the dithered high frequency signal is for directly modulating a light source and a second portion of the dithered high frequency signal is for adjustment by an amplitude and phase adjustment circuit; emitting a light beam from the light source while directly modulating said light source with the first portion of the dithered high frequency signal; externally intensity modulating the light beam emitted from the light source with a phase-adjusted second portion of the dithered high frequency signal in a manner that minimizes the intensity modulation caused by modulation with the first portion of the dithered high frequency signal so as to recover a symmetry of an optical spectrum of the modulated light beam, wherein the frequency of the adjusted second portion of the dithered high frequency signal is at least twice the frequency of the RF information-carrying signal; wherein the RF information-carrying signal and the phase-adjusted second portion of the dithered high frequency signal are pre-distorted by a signal calculated to reduce beat products of the dither tone with higher-order distortions of the RF-information-carrying signal; and coupling into the optical fiber the light beam modulated with the RF information-carrying signal.