Light-induced erasure of self-organized chi((2)) gratings in optical fibers

Self-organized chi((2)) gratings in optical fiber, prepared by irradiating the fiber with 1.06-microm light from a Q-switched mode-locked Nd:YAG laser simultaneously with its second harmonic, can be erased optically. This is accomplished by irradiating the prepared fiber with the 532-nm mode-locked Q-switched light alone, without the 1.06-microm light, or with intense green or blue light from an argon laser. The erasure is reversible, and the fiber can be reprepared as before for second-harmonic conversion. The nonexponential time dependence of the erasure process can be explained by a model involving charge separation during seeding and recombination during erasure.