Fiber based all-optical infinite impulse response filter tuned via stimulated Brillouin scattering

In this paper, we present a novel configuration for an all-fiber tunable infinite impulse response optical filter using stimulated Brillouin scattering. By applying the Brillouin acoustic waves within the coupling area of an optical coupler, we can control its transmissivity and so to affect the spectral response of the IIR optical filter. In this paper, we explain the principle of operation of the proposed device and experimentally demonstrate the ability to control the spectral response of an optical filter based on fiber ring resonator configuration.