Kazimir Y. Kolossovski

Optimization of refractive index sampling for multichannel fiber Bragg gratings

A comprehensive analysis of multichannel grating optimization strategies is presented. The central idea is in dephasing of partial gratings with respect to each other. This dephasing allows the utilization of ultraviolet-induced refractive index changes with maximum efficiency. The dependence of group delay ripple on optimization strategy, number of channels, and other grating characteristics is also briefly discussed. Finally, we discuss further generalization of the dephasing approach to the case of multichannel gratings with nonidentical spectral characteristics.

Three-step design optimization for multi-channel fibre Bragg gratings.

Methods to produce optimal designs for multi-channel fiber Bragg gratings (FBGs) with identical or close to identical channel-to-channel spectral characteristics are discussed. The proposed approach consists of three distinct steps. The first two steps (preliminary semi-analytic minimization and subsequent fine-tuning) do not depend on the grating design details, but on the number of channels only and can be readily applied to similar problems in other fields, e.g., in radio-physics and coding theory. The third step (spectral characteristic quality improvement) is FBG field specific. A comparison with other known optimization methods shows that the proposed approach yields generally superior results for small to moderate number of channels (N < 60).

Stability of higher-order nonlinear modes due to degenerate four-wave mixing

Abstract We present the results of linear stability analysis for families of localized stationary solutions due to degenerate four-wave mixing and report the first example of a stable higher-order soliton family due to degenerate parametric process. We also show a rich variety of possible instability development scenarios for higher-order parametric solitons.

Higherorder solitons: nonlinear dynamics near the oscillatory instability threshold

Nonlinear model describing the dynamics of higher-order solitons near the stability threshold is presented. All major predictions of our theory are in good agreement with the results of direct numerical modeling.