Acousto-optic modulators with a broadened frequency band for fiber-optic lines

The modulator/frequency shifter with single-mode fiber-optic waveguides for a radiation wavelength of 1064 nm has been designed and fabricated. A light beam was focused in the acoustic column center. The switching time of the modulator is $\simeq$ 18 ns. The operation mode is pulse and continuous. The total optical losses at the central frequency are -3.2 dB. The expression for the receiving frequency band of the modulator has been obtained. The estimates of $\simeq$ 40 MHz are in good agreement with the experimental data. We have shown that the use of the focused-beam scheme makes it possible to realize a modulator with a minimum switching time of $\simeq$ 2 – 3 ns and the receiving frequency band of $\simeq$ 200 – 300 MHz.