Spectral Bragg filter with a synthesized transfer function

We suggest the technique of phase-shift keying to synthesize the spectral transfer functions of an optical filter. The phase-shift keying consists in the formation of a reflection grating with several grating cells of equivalent period and amplitude, but different phases. Using a dynamic holographic grating as a filter, we demonstrate a broad set of transfer functions: formation of a controllable local minimum within a central pass band, reconfiguration of a transfer function with a single maximum into a transfer function with 2,3,5,6, and 7 maxima. Furthermore possible applications are discussed.