Spectral pulse transformations and phase transitions in quadratic nonlinear waveguide arrays

Abstract

We study experimentally and numerically the dynamics of a recently found topological phase transition for discrete quadratic solitons with linearly coupled SH waves. We find that, although no stationary states are excited in the experimental situation, the generic feature of the phase transition of the SH is preserved. By utilizing simulations of the coupled mode equations we identify the complex processes leading to the phase transition involving spatial focusing and the generation of new frequency components. These distinct signatures of the dynamic phase transition are also demonstrated experimentally.

Temporal dynamics of spatially localized waves in quadratic nonlinear waveguide arrays

“…This is achieved through the so-called cascading nonlinearity [16], where the generation of a second harmonic (SH) field and its back conversion to the fundamental wave (FW) of twice the SH wavelength result in an overall nonlinear phase shift similar to the one generated by a cubic nonlinearity. Recently, the measurement of pulse spectra in quadratic nonlinear WGAs has led to theoretical predictions of unusual temporal pulse dynamics [17], which are awaiting experimental verification. While temporal reshaping of pulsed all-optical switching was already characterized in two coupled * f.setzpfandt@uni-jena.de waveguides [18], the characterization of the full spatiotemporal dynamics of optical signals in quadratic WGAs has not yet been reported.…”

Focus issue introduction: nonlinear optics

“…Eilenberger et al [17] describes light bullet propagation and decay in such arrays, and Setzpfandt et al [18] analyzes dynamics of solitons in second-order arrayed media. Both papers provide comprehensive introductions describing significant recent progress achieved in this active area.…”

Focus issue introduction: nonlinear optics

“…There are two papers in the Waveguide Arrays category. Eilenberger et al [17] describes light bullet propagation and decay in such arrays, and Setzpfandt et al [18] analyzes dynamics of solitons in second-order arrayed media. Both papers provide comprehensive introductions describing significant recent progress achieved in this active area.…”