Picosecond laser-spectroscopy measurement of hydroxyl fluorescence lifetime in flames.

Data are reported for the first known application of picosecond laser spectroscopy to the measurement of collisional quenching rates by time-resolved laser-induced fluorescence in flames. Collisional quenching rates are important for the determination of species concentrations by laser-induced fluorescence. The collisional quenching lifetime following excitation of the R(2)(4) A(2)Sigma(+) (nu' = 0) ? X(2)II (nu'' = 0) transition was measured to be 1.8 nsec in the burned-gas region of an atmospheric-pressure, premixed methane-air flame.

Long-period fiber-grating-based gain equalizers.

Long-period fiber gratings are used to f latten the gain spectrum of erbium-doped fiber amplifiers. A broadband amplifier with <0.2-dB gain variation over 30 nm is presented. We also show that a chain of amplifiers can be equalized, leading to a bandwidth enhancement by a factor of 3.