Achieving high-efficiency second harmonic generation in a sequence of laser pulses with random peak intensity. Part II. Suppression of intensity fluctuations in a quadratic-nonlinearity medium

The study examines suppression of peak intensity fluctuations in a sequence of fixed-energy femtosecond pulses by so-called cascade second harmonic generation (SHG). In Part II we analyze the propagation of a sequence of subpulses in an optical fiber without self-interaction characterized by cubic nonlinearity and large wavenumber detuning between the principal mode and the second harmonic. The propagation regimes discovered for a sequence of femtosecond pulses ensure suppression of peak intensity fluctuations. The mean peak intensity can be simultaneously increased by chirping the pulses in a particular section and also by adjusting the wavenumber detuning and increasing the quadratic nonlinearity while at the same time reducing to zero the phase of the distribution when the pulses pass to a new part of the nonlinear system. For Part I, See Prikladnaya Matematika i Informatika, No. 27, pp. 5–24, 2007; English Translation: Computational Mathematics and Modeling, Vol. 19, No. 4, pp. 333–342, 2008. Translated from Prikladnaya Matematika i Informatika, No. 28, pp. 5–36, 2008.