Nonlinear spectral blueshift in semiconductor optical amplifiers.

We demonstrate that spectral peak power of negatively chirped optical pulses can acquire a blueshift after amplification by a semiconductor optical amplifier. The central wavelength of a transform limited optical pulse translates over 20 nm towards a shorter wavelength after propagation in a single-mode fiber and semiconductor optical amplifier. A chirped Gaussian pulse with full width at half maximum 1 ps and dimensionless chirp parameter =-20 can be blueshifted by 5 THz.