Revisiting optical phase conjugation by difference-frequency generation

Revisiting the pioneering work of Avizonis et al. [Appl. Phys. Lett. 31, 435 (1977)], we experimentally demonstrate that wave-front reversal of picosecond optical signals carl be efficiently achieved with low-gain parametric amplification. The use of a KTP crystal permits forward phase conjugation of radiation with high divergence (40 mrad) and a broad spectrum (20 nm). The potential application of this this technique to compensate ibr the group-velocity dispersion of standard optical fibers in the 1.55-mu m window is discussed. (C) 1996 Optical Society of America