Frequency-selective filtering and analysis of radio-over-fiber using stimulated Brillouin scattering

A method for tunable microwave-photonic and optical filtering of broadband waveforms is proposed and demonstrated. The principle relies on stimulated Brillouin scattering in standard, birefringent optical fibers, and the associated effect of polarization pulling. The method is employed in the implementation of tunable microwave-photonic band-pass filters with 45 dB selectivity, and in optical spectral analysis of sub-carrier-multiplexed data transmission with tones separation of only 10 MHz.