Ultra-broadband optical parametric amplification based on pre-chirp controlling

For optical parametric amplification with broadband pump coming from the second harmonic of an amplified Ti: sapphire laser syetem, a novel ultra-broad bandwidth phase-matching approach is investigated. The results show that an approximately 400 nm phase-matching bandwidth can be obtained by using a 10 nm pump bandwidth. Moreover, the phase-matching bandwidth can reach 600 nm when the pump bandwidth attains 20nm. In order to obtain temporal overlap of phase-matched spectral components, a linear chirp in the pump requires a quadratic chirp in signal. The photonic crystal fiber with a zero-dispersion wavelength of 800 nm generates a supercontinuum with a quadratic chirp. The broadband pump pulse is stretched to a linear chirped pulse by a prism pairs. Calculations concerning the appropriate length of fiber and prism sequence to be inserted in optical path for the pre-chirp controlling were performed, the results of which provide a theoretical basis for implementing the ultra-broadband optical parametric amplification.