BEAM FANNING AND DOUBLE-PHASE CONJUGATION IN A FIBER-LIKE PHOTOREFRACTIVE SAMPLE

Unexpectedly fast response (35 ms) of beam fanning has been measured i n a fiberlike photorefractive sample of Bi12TiO20 (BTO) crystal. Nonli near interaction between different directions of fanned beams is respo nsible for unusual angular distribution of the fanning emerged from th e fiber that can be used for double phase-conjugate mirror (DPCM) reco rding with higher efficiency in a wider range of the pump's incidence than in a bulk sample, The DPCM with conversion efficiency up to 8% ha s been recorded in the BTO fiber at lambda = 632.8 mn for a 2 x 3 mW i nput light power, Practically, it means that no adjustment is needed t o achieve an effective interaction of mutually incoherent beams, excep t introducing the pump beam into the fiber.