Abstract

Optical fiber pulse compression¹ using an external grating pair has been shown to be a practical technique to generate ultrashort optical pulses. Here we report pulse compression in the near-infrared region using a cw mode-locked Nd:YAG laser operating at 1.319 μm, which gives 125-ps FWHM pulses with the peak power of a few tens of watts coupled into the fiber. The difficulty due to the low power and long duration in the starting pulse can be overcome by the low loss in the fiber at the operating wavelength. We used a few kilometers long dispersion-shifted fiber to achieve enough self-phase modulation and dispersion. Pulses with twice initial width and few nanometers frequency chirping are typically seen at the output end of the fiber. Using a grating pair separated by 7 m in a double-pass configuration, 30× compression, i.e., 4 ps in final pulse, has been obtained. Numerical simulations using a fast-Fourier-transform technique are also performed. The results are in good agreement with the experimental observations.

© 1985 Optical Society of America