OPTICAL FREQUENCY SHIFTER TECHNIQUE BASED ON STIMULATED BRILLOUIN-SCATTERING IN BIREFRINGENT OPTICAL-FIBER

An optical technique for producing a heterodyne carrier frequency suitable for electronic signal-processing schemes in sensing applications is described. The technique exploits stimulated Brillouin scattering (SBS) generated in birefringent optical fiber. Systems based on single-fiber and dual-fiber topologies are reported that yield 10.6 +/- 8.0- and 665 +/- 10.0-MHz carrier frequencies, respectively. Frequency instabilities arose from nonlinear dynamical effects inherent to the SBS process. The implications of the results for future signal-processing and sensing schemes based on SBS are then discussed.