Applications of Nonlinear Optic Effects in New Specialty Fibers

Nonlinear Optic effects are in general higher order processes. This dictates relatively weak interaction coefficients, so that the optical field intensity must be greater in order to observe effects. Optical fiber in particular being amorphous hence centro-symmetric, precludes second order effects, so the ones of interest for this study are already third order X3. Fiber possesses, however, some unique properties which greatly enhance the interaction efficiency, and enable practical applications. The small area confinement typically less than 50 sq um over very long interaction lengths permits up to three orders of magnitude increase in efficiency over a free space focus. Brillouin scatter is examined even though it is not noticeable with normal sources, because key new applications require ultra narrow line widths, which are shown to bring the threshold to a disturbingly low value of only several mw. Stimulated Raman effects are examined because of their great versatility in frequency shifting for various practical applications. Fiber amplification is shown to enable fiber lasers with very promising properties extremely short pulses at very low pump powers, fully integrated with only passive components. Interesting follow-on work is indicated in each of these areas.