Abstract

We present experiments on short pulse spectral compression in the system combining a dispersive delay line and a singlemode fiber at the pico-, subpico-, and 10-femtosecond time scale. This process is the temporal analog of the diffracted beam collimation in a lens. During the dispersive delay, the pulses are stretched and phase modulated (frequency chirped), in analogy to beam diffraction. The further compensation of the accumulated dispersion phase-shift by means of self- or cross-phase modulation (SPM / XPM) in a nonlinear fiber, leads to spectral narrowing¹: the temporal phase-shift induced by Kerr effect in the fiber, like a temporal lens, “collimates” the radiation in time, and “focuses” the spectrum. An application of temporal Kerr-lens for the material characterization problem is the D-scan technique² – a temporal analog of Z-scan method for the measurements of the third order nonlinearity.

© 2000 IEEE