Precise Optical Frequency Shifting Using Stimulated Brillouin Scattering in Optical Fibers

We propose a precise method for optical frequency shifting with high signal-to-noise ratio based on stimulated Brillouin scattering (SBS). The lower sideband of the intensity modulated signal is amplified by the SBS. Also, polarization properties of the SBS are used to further suppress the other sideband and carrier. In addition, the pump wave is locked to the sideband by using software, or lock-in control method. The optical signal can be shifted by 16 GHz with a switching speed of 7 GHz/s. The frequency shifts obtained using our method are very precise because of the high quality radio frequency generator used for the intensity-modulation. Dependent on the type, these RFGs can be adjusted in the milli-Hertz range.