在波导长度上存在缓慢变化的可饱和非线性、色散和pt对称外部电位时的调制不稳定性

IF 2.9 4区物理与天体物理 Q2 OPTICS

Journal of Nonlinear Optical Physics & Materials Pub Date : 2021-11-05 DOI:10.1142/s0218863521500090

V. Sharma

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引用次数: 0

摘要

本文研究了在渐变折射率波导长度上存在缓慢变化的可饱和非线性、群速度色散和pt对称外电位时光波传播的调制不稳定性。我们首先研究了具有空间相关色散和饱和非线性的MI，然后研究了具有恒定色散和饱和非线性的MI。我们解析地计算了增长率，并分析了在群速度色散项和饱和非线性的不同选择下，聚焦非线性和散聚焦非线性存在MI的可能性。我们观察到MI与PT对称势项无关，通常取决于群速度色散项、非线性、饱和非线性和波幅的选择。在聚焦和散焦非线性中，MI增益随连续波幅值的增大而减小，但随饱和非线性的增大而增大。

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Modulation instability in the presence of slowly varying saturable nonlinearity, dispersion and a PT-symmetric external potential over the length of waveguide

We study the modulation instability (MI) for optical wave propagation in the presence of slowly varying saturable nonlinearity, group velocity dispersion and a PT-symmetric external potential over the length of tapered graded-index waveguide. First we study the MI with space-dependent dispersion and saturated nonlinearity and then with constant dispersion and saturated nonlinearity. We analytically compute the growth rate and analyze the possibility of existence of MI for focussing and defocussing nonlinearities for different choices of group velocity dispersion terms and saturated nonlinearities. We observe that MI is independent of PT symmetric potential term and typically depends upon the choice of group velocity dispersion term, nonlinearity, saturated nonlinearity and wave amplitude. MI gain decreases with increase in cw amplitude however it increases with increase in saturated nonlinearity both for focussing and defocussing nonlinearities.

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来源期刊

Journal of Nonlinear Optical Physics & Materials 物理-光学

CiteScore

3.00

自引率

48.10%

发文量

审稿时长

3 months

期刊介绍： This journal is devoted to the rapidly advancing research and development in the field of nonlinear interactions of light with matter. Topics of interest include, but are not limited to, nonlinear optical materials, metamaterials and plasmonics, nano-photonic structures, stimulated scatterings, harmonic generations, wave mixing, real time holography, guided waves and solitons, bistabilities, instabilities and nonlinear dynamics, and their applications in laser and coherent lightwave amplification, guiding, switching, modulation, communication and information processing. Original papers, comprehensive reviews and rapid communications reporting original theories and observations are sought for in these and related areas. This journal will also publish proceedings of important international meetings and workshops. It is intended for graduate students, scientists and researchers in academic, industrial and government research institutions.