On the theory of the modulation instability in optical fiber amplifiers.

The modulation instability (MI) in optical fiber amplifiers and lasers with anomalous dispersion leads to cw radiation breakup. This can be both a detrimental effect limiting the performance of amplifiers and an underlying physical mechanism in the operation of MI-based devices. Here we revisit the analytical theory of MI in fiber optical amplifiers.

Modulation instability in high power laser amplifiers.

The modulation instability (MI) is one of the main factors responsible for the degradation of beam quality in high-power laser systems. The so-called B-integral restriction is commonly used as the criteria for MI control in passive optics devices. For amplifiers the adiabatic model, assuming locally the Bespalov-Talanov expression for MI growth, is commonly used to estimate the destructive impact of the instability.

Sub-critical regime of femtosecond inscription.

We apply well known nonlinear diffraction theory governing focusing of a powerful light beam of arbitrary shape in medium with Kerr nonlinearity to the analysis of femtosecond (fs) laser processing of dielectric in sub-critical (input power less than the critical power of self-focusing) regime. Simple analytical expressions are derived for the input beam power and spatial focusing parameter (numerical aperture) that are required for achieving an inscription threshold. Application of non-Gaussian laser beams for better controlled fs inscription at higher powers is also discussed.

Autosolitons in dispersion-managed systems with in-line saturable absorbers.

We study the formation of stable solitonlike pulses in dispersion-managed fiber transmission systems using an in-line fast saturable absorber. Operational regimes suitable for 40-Gbit/s channel rate transmission are demonstrated.

Path-averaged optical soliton in double-periodic dispersion-managed systems.

A path-averaged Gabitov-Turitsyn model governing optical signal propagation down the dispersion-managed (DM) transmission line is studied numerically. A different numerical algorithm to find a soliton solution for an arbitrary periodic DM system is proposed. Applying developed technique we analyze soliton solutions for few important practical systems.