Study of Acousto-Optical Filter Characteristics in Frequency Modulation Mode

The bench is designed and assembled for studying acousto-optical tunable filters (AOTF) operating in frequency modulation mode ∆f(t). Specialized software for a formation of frequency-modulated signals of various type and for spectral data detection and processing was developed. For a class of power functions ∆f ∼ t
ⁿ
there were investigated AOTF spectral characteristics depending on power index n. It was revealed bandpass widening and asymmetric deformations of the transmission function shape. Another class of studied non-linear modulation functions dependencies is root-law dependency ∆f ∼ t
^1/n
. It was demonstrated that the transmission function transformations with n rising are quite similar. It also shown that high orders of index n provide transmission function window looking like a narrow bandpass on top of wide-band pedestal.