Synthesis of picosecond pulses by spectral compression and shaping of femtosecond pulses in engineered quadratic nonlinear media.

Narrow-bandwidth picosecond pulses of predetermined spectral and temporal shapes are generated with high efficiency by frequency conversion of femtosecond pulses in lithium tantalate crystals with engineered quasi-phase-matching structures. We give examples of the synthesis of Gaussian and super-Gaussian picosecond pulses and also of a pair of synchronized phase-coherent picosecond pulses with a predetermined carrier-frequency difference.

Narrow-bandwidth picosecond pulses by spectral compression of femtosecond pulses in second-order nonlinear crystals.

We introduce a simple approach for the efficient generation of tunable narrow-bandwidth picosecond pulses synchronized to broadband femtosecond ones. Second harmonic generation in the presence of large group velocity mismatch between the interacting pulses transfers a large fraction of the energy of a broadband fundamental frequency pulse into a narrowband second harmonic one. Using a periodically poled stoichiometric lithium tantalate crystal coupled to an infrared optical parametric amplifier, we generated 200-nJ pulses with spectral width lower than 8.5 cm(-1) and tunability from 720 to 890 nm. Energy scaling and extension of the tuning range are straightforward.

Stability and optimization of dispersion-managed soliton control.

Dispersion-managed solitons with in-line all-optical regeneration are shown to be subject to amplitude and timing-jitter instabilities. We identify and discuss the different natures of these instabilities by means of a linear stability analysis, which is in good agreement with the full numerical solutions of the governing equations. Stable pulse propagation can be achieved through appropriate choices of dispersion map and pulse energy.