【摘要】：宇稱時(shí)間(parity-time；簡(jiǎn)稱PT)對(duì)稱波導(dǎo)是近年來發(fā)現(xiàn)的一種新型光學(xué)波導(dǎo)。由于該波導(dǎo)具有許多獨(dú)特的光學(xué)性質(zhì),因而在光子信息處理以及集成光學(xué)方面具有重要的潛在應(yīng)用價(jià)值。特別是隨著PT對(duì)稱在光學(xué)實(shí)驗(yàn)上的實(shí)現(xiàn),更加激發(fā)了人們對(duì)它的廣泛關(guān)注。PT對(duì)稱的概念最初來自量子力學(xué)。PT對(duì)稱要求薛定諤方程中勢(shì)能函數(shù)的實(shí)部是位置坐標(biāo)的偶函數(shù),而虛部是位置坐標(biāo)的奇函數(shù)。在光學(xué)中,PT對(duì)稱可通過波導(dǎo)的復(fù)折射率實(shí)現(xiàn)。它要求波導(dǎo)的折射率分布呈偶對(duì)稱,而增益/損耗分布呈奇對(duì)稱。本文主要基于光波在PT對(duì)稱波導(dǎo)中傳輸?shù)睦碚撃Ｐ?數(shù)值研究亮孤子和高斯光波在呈高斯分布的PT對(duì)稱克爾非線性平板波導(dǎo)中的傳輸和控制。具體內(nèi)容包括以下四個(gè)方面：(1)分別介紹空間光孤子的研究進(jìn)展,PT對(duì)稱的基本概念、發(fā)展現(xiàn)狀和應(yīng)用。(2)利用Maxwell方程組推導(dǎo)出空間光波在非線性介質(zhì)中傳輸?shù)囊话憷碚撃Ｐ?然后通過該理論模型推導(dǎo)出空間光波在PT對(duì)稱克爾非線性波導(dǎo)中的傳輸模型。(3)根據(jù)光波在PT對(duì)稱波導(dǎo)中的傳輸模型,數(shù)值地討論亮孤子在高斯型PT對(duì)稱波導(dǎo)中的傳輸和控制。研究結(jié)果發(fā)現(xiàn)：當(dāng)波導(dǎo)的折射率分布強(qiáng)度為正時(shí),PT對(duì)稱波導(dǎo)的中心折射率最大,即使沒有自聚焦克爾非線性效應(yīng),PT對(duì)稱波導(dǎo)也可以束縛光波,形成波浪形光束且長(zhǎng)距離傳輸。當(dāng)折射率分布強(qiáng)度為負(fù)時(shí),PT對(duì)稱波導(dǎo)中的中心折射率最小,亮孤子的傳輸方向發(fā)生偏移。而增益/損耗分布可控制光孤子的偏移方向。且當(dāng)折射率分布強(qiáng)度為負(fù)時(shí),可以很好地抑制相鄰亮孤子間的相互作用。(4)此外基于上述模型,通過數(shù)值模擬的方法進(jìn)一步討論基階、二階、三階高斯光波在高斯型PT對(duì)稱波導(dǎo)中的傳輸。研究結(jié)果表明：在PT對(duì)稱波導(dǎo)中,基階高斯光波傳輸隨著折射率分布強(qiáng)度的增加,傳輸越來越穩(wěn)定,而且光波在傳輸?shù)倪^程中,光束由波浪形逐漸轉(zhuǎn)變?yōu)橹本�形。二階高斯光波在PT對(duì)稱波導(dǎo)中形成了兩束波浪形的光波,兩束光波出現(xiàn)了能量的交替現(xiàn)象。三階高斯光波則需要足夠大的折射率分布強(qiáng)度,才能穩(wěn)定傳輸。
[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.
【學(xué)位授予單位】：太原理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TN252

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相關(guān)期刊論文 前2條

1 李春艷;黃長(zhǎng)明;董亮偉;;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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本文編號(hào)：2355455