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光波在高斯型宇称时间对称波导中的传输和控制

发布时间:2018-11-25 08:31
【摘要】:宇称时间(parity-time;简称PT)对称波导是近年来发现的一种新型光学波导。由于该波导具有许多独特的光学性质,因而在光子信息处理以及集成光学方面具有重要的潜在应用价值。特别是随着PT对称在光学实验上的实现,更加激发了人们对它的广泛关注。PT对称的概念最初来自量子力学。PT对称要求薛定谔方程中势能函数的实部是位置坐标的偶函数,而虚部是位置坐标的奇函数。在光学中,PT对称可通过波导的复折射率实现。它要求波导的折射率分布呈偶对称,而增益/损耗分布呈奇对称。本文主要基于光波在PT对称波导中传输的理论模型,数值研究亮孤子和高斯光波在呈高斯分布的PT对称克尔非线性平板波导中的传输和控制。具体内容包括以下四个方面:(1)分别介绍空间光孤子的研究进展,PT对称的基本概念、发展现状和应用。(2)利用Maxwell方程组推导出空间光波在非线性介质中传输的一般理论模型,然后通过该理论模型推导出空间光波在PT对称克尔非线性波导中的传输模型。(3)根据光波在PT对称波导中的传输模型,数值地讨论亮孤子在高斯型PT对称波导中的传输和控制。研究结果发现:当波导的折射率分布强度为正时,PT对称波导的中心折射率最大,即使没有自聚焦克尔非线性效应,PT对称波导也可以束缚光波,形成波浪形光束且长距离传输。当折射率分布强度为负时,PT对称波导中的中心折射率最小,亮孤子的传输方向发生偏移。而增益/损耗分布可控制光孤子的偏移方向。且当折射率分布强度为负时,可以很好地抑制相邻亮孤子间的相互作用。(4)此外基于上述模型,通过数值模拟的方法进一步讨论基阶、二阶、三阶高斯光波在高斯型PT对称波导中的传输。研究结果表明:在PT对称波导中,基阶高斯光波传输随着折射率分布强度的增加,传输越来越稳定,而且光波在传输的过程中,光束由波浪形逐渐转变为直线形。二阶高斯光波在PT对称波导中形成了两束波浪形的光波,两束光波出现了能量的交替现象。三阶高斯光波则需要足够大的折射率分布强度,才能稳定传输。
[Abstract]:Parity time (parity-time;) symmetric waveguide (PT) is a new optical waveguide discovered in recent years. Because the waveguide has many unique optical properties, it has important potential applications in photonic information processing and integrated optics. Especially, with the realization of PT symmetry in optical experiment, people pay more attention to it. The concept of PT symmetry comes from quantum mechanics. PT symmetry requires that the real part of potential energy function in Schrodinger equation is even function of position coordinate. The imaginary part is an odd function of the position coordinates. In optics, PT symmetry can be achieved by the complex refractive index of the waveguide. It requires that the refractive index distribution of the waveguide is even-symmetric, while the gain / loss distribution is odd-symmetric. Based on the theoretical model of optical wave propagation in PT symmetric waveguide, the transmission and control of bright solitons and Gao Si optical waves in a PT symmetric Kerr nonlinear plate waveguide are numerically studied in this paper. The main contents are as follows: (1) the research progress of spatial soliton and the basic concept of PT symmetry are introduced respectively. (2) the general theoretical model of spatial light wave propagation in nonlinear media is derived by using Maxwell equations. Then the propagation model of spatial light waves in PT symmetric Kerr nonlinear waveguides is derived from the theoretical model. (3) according to the propagation model of light waves in PT symmetric waveguides, The propagation and control of bright solitons in Gao Si type PT symmetric waveguide are discussed numerically. The results show that when the intensity of refractive index distribution of the waveguide is positive, the central refractive index of the PT symmetric waveguide is the largest. Even without the self-focusing Kerr nonlinear effect, the PT symmetric waveguide can bind the light wave. A wave beam is formed and propagates over a long distance. When the intensity of refractive index distribution is negative, the central refractive index in PT symmetric waveguide is the smallest and the propagation direction of bright soliton is offset. The gain / loss distribution can control the shift direction of the soliton. When the intensity of refractive index distribution is negative, the interaction between adjacent bright solitons can be suppressed very well. (4) based on the above model, the fundamental order and the second order are further discussed by numerical simulation. The propagation of third order Gao Si light wave in Gao Si type PT symmetrical waveguide. The results show that with the increase of refractive index distribution intensity, the propagation of fundamental order Gao Si light wave in PT symmetrical waveguide becomes more and more stable, and in the process of optical wave propagation, the beam gradually changes from wave shape to straight shape. The second order Gao Si light wave forms two waves in the PT symmetrical waveguide, and the two light waves appear the energy alternant phenomenon. The third order Gao Si light wave needs high enough intensity of refractive index distribution in order to transmit stably.
【学位授予单位】:太原理工大学
【学位级别】:硕士
【学位授予年份】:2015
【分类号】:TN252

【参考文献】

相关期刊论文 前2条

1 李春艳;黄长明;董亮伟;;Stabilization of optical solitons in chirped PT-symmetric lattices[J];Chinese Physics B;2013年07期

2 胡素梅;胡巍;;Defect solitons supported by parity-time symmetric defects in superlattices[J];Chinese Physics B;2013年07期



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