Device for increasing the spectral bandwidth of optical pulses as well as an arrangement and a method for reducing the duration of optical pulses with the use of such a device

A method for reducing the duration of optical pulses comprising the steps of:

• coupling light pulses by means of focusing optics into a hollow fiber waveguide that has an input end and an output end, and is contained in an air-tight chamber filled with a gas,
• setting the length of the hollow fiber waveguide such that, for a given input pulse energy and gas pressure, the energy contained in a fundamental propagation mode, LP01, that has minimum propagation losses exhibits substantially periodic oscillations over the full length of the hollow fiber waveguide and reaches a local maximum at the output end of the hollow fiber waveguide;
• enlarging the bandwidth of the said optical pulses by means of nonlinear propagation in the gas-filled hollow fiber waveguide;
• spatially re-collimating the optical pulses by optical means after exiting at the output end of the hollow fiber waveguide and the air-tight chamber;
• and
• propagating the spectrally broadened optical pulses through a group delay dispersion compensation device where their duration is reduced.