### Abstract

Language | English |
---|---|

Pages | 812-820 |

Number of pages | 9 |

Journal | Journal of the Optical Society of America B-Optical Physics |

Volume | 30 |

Issue number | 4 |

Early online date | 6 Mar 2013 |

DOIs | |

Status | Published - 2013 |

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**Dispersion of nonlinearity in subwavelength waveguides: derivation of pulse propagation equation and frequency conversion effects.** / Zhao, Xuesong; Gorbach, Andriy V; Skryabin, Dmitry V.

Research output: Contribution to journal › Article

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TY - JOUR

T1 - Dispersion of nonlinearity in subwavelength waveguides: derivation of pulse propagation equation and frequency conversion effects

AU - Zhao,Xuesong

AU - Gorbach,Andriy V

AU - Skryabin,Dmitry V

PY - 2013

Y1 - 2013

N2 - Description of pulse propagation in waveguides with subwavelength features and high refractive index contrasts requires an accurate account of the dispersion of nonlinearity due to the considerable mode profile variation with the wavelength. The corresponding model derived from asymptotic expansion of Maxwell equations contains a complicated network of interactions between different harmonics of the pulse, and therefore is not convenient for analysis. We demonstrate that this model can be reduced to the generalized nonlinear Schrödinger-type pulse propagation equation under the assumption of factorization of the four-frequency dependence of nonlinear coefficients. We analyze two different semiconductor waveguide geometries and find that the factorization works reasonably well within large wavelength windows. This allows us to utilize the pulse propagation equation for the description of a broadband signal evolution. We study the mechanism of modulational instability induced by the dispersion of nonlinearity and find that the power threshold predicted by the simple model with three interacting harmonics is effectively removed when using pulses, while the efficiency of this process grows for shorter pulse durations. Also, we identify the effects of geometrical and material dispersion of nonlinearity on spectral broadening of short pulses in semiconductor waveguides.

AB - Description of pulse propagation in waveguides with subwavelength features and high refractive index contrasts requires an accurate account of the dispersion of nonlinearity due to the considerable mode profile variation with the wavelength. The corresponding model derived from asymptotic expansion of Maxwell equations contains a complicated network of interactions between different harmonics of the pulse, and therefore is not convenient for analysis. We demonstrate that this model can be reduced to the generalized nonlinear Schrödinger-type pulse propagation equation under the assumption of factorization of the four-frequency dependence of nonlinear coefficients. We analyze two different semiconductor waveguide geometries and find that the factorization works reasonably well within large wavelength windows. This allows us to utilize the pulse propagation equation for the description of a broadband signal evolution. We study the mechanism of modulational instability induced by the dispersion of nonlinearity and find that the power threshold predicted by the simple model with three interacting harmonics is effectively removed when using pulses, while the efficiency of this process grows for shorter pulse durations. Also, we identify the effects of geometrical and material dispersion of nonlinearity on spectral broadening of short pulses in semiconductor waveguides.

UR - http://www.scopus.com/inward/record.url?scp=84877630859&partnerID=8YFLogxK

UR - http://dx.doi.org/10.1364/JOSAB.30.000812

U2 - 10.1364/JOSAB.30.000812

DO - 10.1364/JOSAB.30.000812

M3 - Article

VL - 30

SP - 812

EP - 820

JO - Journal of the Optical Society of America B-Optical Physics

T2 - Journal of the Optical Society of America B-Optical Physics

JF - Journal of the Optical Society of America B-Optical Physics

SN - 0740-3224

IS - 4

ER -