抄録
Generating mechanism of the optical feedback noise in semiconductor lasers and whose suppressing manner by utilizing the self-pulsation laser or the high frequency superposition method are theoretically reviewed. Those mechanisms are characterized in terms of the mode competition phenomena among the internal cavity modes of the solitary laser and the external cavity modes which are built up by the optical feedback. Suppression of the feedback noise is understood as an effect to shift the operating point to more stable state by help of the modulated photons and electron densities in the laser.
