Romstad, Francis Pascal4; Borri, Paola2; Langbein, Wolfgang Werner2; Mørk, Jesper1; Hvam, Jørn Märcher1
1 Department of Photonics Engineering, Technical University of Denmark2 Department of Micro- and Nanotechnology, Technical University of Denmark3 Nanophotonics Theory and Signal Processing, Department of Photonics Engineering, Technical University of Denmark4 IT Service, Administration, Technical University of Denmark
We have performed extensive measurements of the propagation of ultrashort pulses in a semiconductor bulk amplifier using an ultrasensitive cross frequency-resolved optical gating technique. Pulses of 175-fs duration with energies from below 1 fJ to above 100 pJ are measured both in amplitude and phase after propagation through the device. While only moderate reshaping effects occur at pulse energies of below 1 pJ, strong amplitude distortion together with nonlinear chirp is found for input energies of 5-100 pJ. This leads to a pulse narrowing by more than a factor of two when the amplifier is biased for material transparency or absorption and to a pronounced pulse breakup in the gain regime.
I E E E Photonics Technology Letters, 2000, Vol 12, Issue 12, p. 1674-1676