Bright Soliton-Like Pulses in Self-Defocusing Material

Abstract

Temporal bright solitons are well known and still studied because they provide a great potential in long distance lightwave systems. Bright temporal solitons have been observed [1] in silica fiber in which the Kerr nonlinearity (n2) is positive and the dispersion anomalous (β2<0). Since bright solitons exist as long as n2 and β2 are of opposite sign, another regime is possible and was observed recently [2] near the band gap in AlGaAs waveguide having a self-defocusing nonlinearity and normal dispersion. In this case, the solitonic feature can be deduced from a temporal narrowing of the pulse with increasing input pulse peak power. For pulses of increasing peak power, the self-phase modulation better compensates the dispersion. Nevertheless it still not possible to conclude in a solitonic phenomenon in a strict way since no information was obtain about the spectrum. If an important spectral broadening with increasing pulse peak power occurs, it would clearly deny the soliton hypothesis. In this presentation we propose to introduce spectral measurements and to qualify the pulse behavior.