ACOUSTOOPTICAL TUNABLE FILTER Russian patent published in 2002 - IPC

FIELD: integrated and fiber optics. SUBSTANCE: given acoustooptical tunable filter can be employed for frequency channeling of signals in fiber-optical communication systems and as small-sized tunable optical spectrometer. Acoustooptical tunable filter is planar optical waveguide with acoustooptical cell in which or close to which elements forming and/or selecting optical beams in the form of two strip optical waveguides and set of elementary reflectors overlapping apertures of proper strip optical waveguides through which incident and output beams correspondingly pass are produced. Angle of inclination of elementary reflectors of forming element is chosen on condition that specular beams are directed at Bragg angle for incident wave. Angle of inclination of elementary reflectors of selecting element is chosen on condition that specular light beams going out of strip waveguide are directed at Bragg angle for diffracted light wave of acoustooptical cell. To secure passage of deviated diffracted beam alone through output strip waveguide relative angle of inclination of specular beams of forming and selecting elements is chosen greater than angle of diffraction divergence of light beams reflected from elementary reflectors. Positions of elementary reflectors are chosen such that directions of propagation of one of order of interference from various elementary reflectors correspondingly match directions specified by specular beams passing from strip optical waveguides to planar optical waveguide on central length of wave of optical radiation of tunable filter. For better suppression of spurious signals outside bandwidth of filter elementary reflectors are chosen with variable reflection factors and elementary reflectors of forming and/or selecting elements are displaced relative to periodic positions in order to expand band of delay of signals outside bandwidth of filter. EFFECT: development of acoustooptical tunable filter with minimal dimensions, narrow line of bandwidth in tuning band and high efficiency of suppression of spurious signals outside bandwidth of filter. 2 cl, 9 dwg