A notch filter acoustically induced in a 1-cm-longchirped fiber Bragg grating is experimentally investigated.The notch reflectivity (−5.8 to −32 dB) and the bandwidth(2.2 to 1.3 nm) are tuned by an electrical signal. The reduction of the modulator size and the grating length, compared with previous works with acousto-optic modulation, points to more efficient acousto-optic devices in standard single-mode optical fibers.