Adiabatic compression of quadratic temporal solitons in aperiodic quasi-phase-matching gratings

Abstract

We numerically show that it is possible to achieve adiabatic compression of femtosecond quadratic solitons in aperiodically poled lithium niobate device. Two-colored solitons of the fundamental wavelength of 1560 nm can be adiabatically shaped by using group-velocity matching schemes available in quasi-phase-matching (QPM) devices. We investigate the performance of the adiabatic compression based on two different group-velocity matching schemes: type-I (e: o + o) collinear QPM geometry and type-0 (e: e + e) non-collinear QPM geometry. Two-colored temporal solitons with pulse duration of 35 fs are generated without visible pedestals from 100-fs fundamental pulse. We also show that walking solitons with shorter pulse durations are adiabatically excited under small group-velocity mismatch condition. The walking solitons experience deceleration or acceleration during compression, depending on the sign of the groupvelocity- mismatch. The demonstrated adiabatic pulse shaping is useful for generation of shorter pulses with clean temporal profiles, efficient femtosecond second harmonic generation and group-velocity control.

Wavelength-tunable slow light of fs laser pulse by quadratic nonlinear cascading process

“…In addition, the energy of the signal increased because of the supplement from the pump. The compression of the pulse width is similar as the soliton compression mentioned by Zeng et al [9].…”

Spectral shaping of femtosecond pulses in aperiodic quasi-phase-matched gratings

“…Transverse quasi-phase-matched gratings have been made both for shaping of second harmonic beams [9] and to extend the spectral coverage of optical parametric oscillators [10]. Pulse compression, gain conversion [11,12] and spectral shift [13] enhancement in frequency-conversion schemes in longitudinally chirped quasi-phase-matched gratings have been demonstrated. More recently the issue of arbitrary second-harmonic pulse shaping in aperiodically poled crystals was solved by means of both optimal control and simulated annealing techniques [14][15][16].…”

Soliton compression to few-cycle pulses with a high quality factor by engineering cascaded quadratic nonlinearities

“…Quasi-phase-matching (QPM) technique offer additional degrees of freedom controlling cascaded nonlinearities, depending on the effective phase mismatch. Through engineering the QPM structure, adiabatic and high-quality pulse formation of quadratic soliton was presented [10,11].…”