發(fā)布時(shí)間：2017-12-28 09:13

  本文關(guān)鍵詞：新型少模光纖波導(dǎo)特性分析及其器件的研制　出處：《北京交通大學(xué)》2016年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 少模光纖 光纖器件 大模場(chǎng)面積 單偏振 光纖激光器

【摘要】：新型大模場(chǎng)面積少模光纖(few-mode fiber, FMF)對(duì)下一代高速大容量無阻塞光通信系統(tǒng)、光纖傳感技術(shù)與光纖激光器的研究具有十分重要的價(jià)值。模分復(fù)用系統(tǒng)充分利用FMF中多個(gè)正交模式作為獨(dú)立信道和大模場(chǎng)面積等優(yōu)勢(shì),大大提升光纖通信系統(tǒng)的通信容量,有效地解決光纖非線性效應(yīng)引起的通信容量瓶頸問題,為下一代光纖通信系統(tǒng)提供重要保障。本論文主要針對(duì)多芯層少模光纖(multilayer-core FMF, MC-FMF)開展理論與實(shí)驗(yàn)研究工作。重點(diǎn)研究MC-FMF的結(jié)構(gòu)設(shè)計(jì)與制作,并將MC-FMF應(yīng)用于新型光纖器件的實(shí)現(xiàn)。在理論分析與應(yīng)用研究過程中,深入認(rèn)識(shí)了光纖結(jié)構(gòu)參數(shù)與其特性之間的本質(zhì)關(guān)系。大部分工作均處于該領(lǐng)域研究的前沿。本文主要取得的創(chuàng)新研究成果如下：1.提出并設(shè)計(jì)制作了一種新型MC-FMF,指出了光纖結(jié)構(gòu)參數(shù)對(duì)波導(dǎo)特性影響的規(guī)律。通過光纖結(jié)構(gòu)參數(shù)的優(yōu)化調(diào)整,實(shí)現(xiàn)了波導(dǎo)中模式數(shù)量的控制,以及大模場(chǎng)面積與低彎曲損耗等良好性能的集成。建立了四芯層結(jié)構(gòu)FMF的數(shù)學(xué)模型,采用數(shù)值方法計(jì)算了光纖特征參數(shù)。采用MCVD工藝實(shí)驗(yàn)制作了大模場(chǎng)面積低彎曲損耗的雙模光纖(dual-mode fiber, DMF)樣本。該DMF的基模模場(chǎng)面積可達(dá)280μm2,是普通單模光纖的四倍；在4.5cm彎曲半徑條件下,光纖損耗可低至0.42dB/turn。建立了光纖準(zhǔn)直器幾何冗余度同尾纖模場(chǎng)面積之間關(guān)系的數(shù)學(xué)模型。利用多芯層結(jié)構(gòu)光纖(multilayer-core fiber, MCF)的大模場(chǎng)面積特性,首次制作了基于MCF的光纖準(zhǔn)直器。與普通單模光纖準(zhǔn)直器相比其偏角冗余值提升了20%,降低了準(zhǔn)直器用于空間光耦合的難度。2.提出并設(shè)計(jì)制作了一種嚴(yán)格雙模的多橢圓芯層光纖(elliptical multilayer-core fiber, EMCF),指出了EMCF結(jié)構(gòu)參數(shù)對(duì)雙折射、非線性等特征參量影響的規(guī)律,發(fā)現(xiàn)了EMCF具有明顯的偏振保持特性。針對(duì)彎曲狀態(tài)下的非圓對(duì)稱結(jié)構(gòu)光纖,建立了EMCF折射率分布與傳輸損耗的計(jì)算模型。模型充分考慮了光纖結(jié)構(gòu)對(duì)折射率分布的影響以及與光纖彎曲損耗相關(guān)的因素,從本質(zhì)上揭示了EMCF在彎曲方向上產(chǎn)生彎曲損耗差異性的原因,表明該光纖具有各向異性的彎曲特性。實(shí)際制作出嚴(yán)格雙模的EMCF樣本,在適當(dāng)彎曲半徑與方向下,EMCF的基模中兩偏振分量的彎曲損耗曲線發(fā)生走離,實(shí)現(xiàn)了單一偏振的低損耗傳輸。3.提出并研制了一種基于FMF的模式干涉器件。基于模式耦合理論,揭示了該光纖器件中的模式耦合過程。提出了兩段非圓對(duì)稱結(jié)構(gòu)EMCF的熔接方案,使用EMCF實(shí)際制作了全光纖的馬赫增德爾干涉儀(Mach-Zehnder interferometer, MZI)與邁克爾遜干涉儀(Michelson interferometer, MI)。在對(duì)基于FMF干涉器件傳感原理的充分認(rèn)識(shí)和理解的基礎(chǔ)上,提出了應(yīng)力與液位兩參量傳感的仿真方法。實(shí)際搭建了基于FMF的溫度、應(yīng)力、折射率、液位等物理量的傳感系統(tǒng),實(shí)現(xiàn)了其傳感功能。提出并搭建了基于FMF的激光傳感系統(tǒng),顯著提升了傳感系統(tǒng)的分辨率。制作了一種以FMF-MI為濾波器的環(huán)型腔激光器,并用FMF-MI作為傳感頭實(shí)現(xiàn)了液位傳感測(cè)量。液位的變化可調(diào)諧激光器輸出波長(zhǎng)。激光傳感系統(tǒng)的輸出激光消光比達(dá)到了43dB,遠(yuǎn)大于FMF-MI濾波器輸出光譜的消光比：3dB帶寬約為0.05nm,遠(yuǎn)小于濾波器輸出光譜的3dB帶寬,顯著提升了液位傳感的分辨率；實(shí)驗(yàn)測(cè)得該傳感系統(tǒng)的液位傳感靈敏度約為50.6pm/mm。4.提出并制作了一種少模布拉格光纖光柵(few-mode fiber Bragg grating, FM-FBG)。該FM-FBG的光纖載體僅支持LPo0與LP11兩個(gè)模式場(chǎng)的傳輸,因此其反射和透射光譜中同時(shí)存在模式自耦合峰和模式場(chǎng)間互耦合峰。利用耦合模方程建立了該光柵的解析模型,揭示了FM-FBG的模式耦合過程,為進(jìn)一步研究與求解FM-FBG特征參量提供了理論基礎(chǔ)。通過仿真計(jì)算,找出了FMF中模式能量比、模式折射率差與耦合系數(shù)等參數(shù)分別對(duì)FM-FBG中諧振點(diǎn)強(qiáng)度、帶寬、波長(zhǎng)間隔等特性影響的規(guī)律。實(shí)際制作了基于FM-FBG的雙波長(zhǎng)可調(diào)諧激光器,利用EDF的光譜燒孔(SHB)效應(yīng),方便地實(shí)現(xiàn)了激光器單波長(zhǎng)與雙波長(zhǎng)狀態(tài)的轉(zhuǎn)換。利用FM-FBG中LP01自耦合透射峰和LP01與LPn互耦合透射峰的濾波特性,在線型腔結(jié)構(gòu)中實(shí)現(xiàn)了穩(wěn)定的單橫模輸出(基模LP01)和LP01與LP11混合的多橫模激光輸出。
[Abstract]:The new large mode area few-mode fiber (FMF) is of great value for the next generation of high-speed and high-capacity non blocking optical communication system, optical fiber sensing technology and fiber laser. Make full use of multiple orthogonal FMF model as an independent channel and large mode area advantages in mode division multiplexing system, greatly enhance the communication capacity of optical communication system, effectively solve the bottleneck problem of communication capacity caused by the nonlinear effect of optical fiber, provide an important guarantee for the next generation of optical fiber communication system. This thesis focuses on the theoretical and Experimental Research on multilayer-core FMF (MC-FMF) with multi core layer. The structure design and production of MC-FMF are emphatically studied, and MC-FMF is applied to the realization of the new optical fiber device. In the process of theoretical analysis and application, the essential relationship between the parameters of optical fiber structure and its characteristics is deeply understood. Most of the work is at the forefront of the research in this field. The main achievements of this paper are as follows: 1. a new MC-FMF is proposed and designed, and the influence of fiber structure parameters on waveguide characteristics is pointed out. Through the optimization and adjustment of the optical fiber structure parameters, the control of the mode number in the waveguide and the integration of the good performance of the large mode field area and low bending loss are realized. The mathematical model of the four core layer structure FMF is set up, and the characteristic parameters of the fiber are calculated by numerical method. A double mode fiber (dual-mode fiber, DMF) sample of large mode field area with low bending loss was made by MCVD process. The base mode field area of the DMF can reach 280 mu m2, which is four times of the ordinary single mode fiber, and the fiber loss can be as low as 0.42dB/turn under the 4.5cm bending radius. The establishment of mathematical model of the relationship between fiber collimator geometric redundancy with the fiber mode field area. The optical fiber collimator based on MCF is made for the first time using the large mode field area characteristics of multilayer-core fiber (MCF). Compared with the ordinary single mode fiber collimator, the redundancy of the deflection angle of the collimator is increased by 20%, which reduces the difficulty of the collimator for the spatial light coupling. 2., we propose and design a strict double mode elliptical multilayer-core fiber (EMCF). We point out the influence of EMCF's structural parameters on birefringence and nonlinearity. We find that EMCF has obvious polarization maintaining property. The calculation model of the refractive index distribution and transmission loss of EMCF is established for the non circular symmetric structural fiber under the condition of bending. Considering the influence of fiber structure on the refractive index distribution and the factors related to the bending loss of optical fibers, the model reveals the reason of the difference in bending loss of EMCF in bending direction, which indicates that the fiber has anisotropic bending properties. Actually, a strict dual-mode EMCF sample is made, and the bending loss curve of the two polarization component is removed in the basic mode of EMCF under the proper bending radius and direction, and a single polarization low loss transmission is realized. 3. a model interferometer based on FMF is proposed and developed. Based on the mode coupling theory, the mode coupling process in the optical fiber device is revealed. A scheme of EMCF fusion is presented for two non-circular symmetric structures. The EMCF Mach-Zehnder interferometer (Mach-Zehnder interferometer MZI) and Michelson interferometer (Michelson interferometer MI) are fabricated by EMCF. On the basis of full understanding and understanding of the sensing principle based on FMF interferometer, a simulation method of stress and liquid level two parameter sensing is proposed. The sensing system based on the physical quantity of temperature, stress, refractive index, liquid level and so on, which is based on FMF, has been built, and its sensing function is realized. A laser sensing system based on FMF has been proposed and built, which greatly improves the resolution of the sensing system. A ring cavity laser with FMF-MI as the filter is made, and the liquid level sensing measurement is realized by using FMF-MI as the sensor head. The change of the liquid level can be tuned to the output wavelength of the laser. The laser sensor system output laser extinction ratio reached 43dB, far greater than FMF-MI the output spectrum of the filter extinction ratio: 3dB bandwidth is about 0.05nm, far less than the output spectrum of the filter bandwidth of 3dB, significantly enhance the resolution of liquid level sensing; measured the sensing system experimental position sensing sensitivity is about 50.6pm/mm. 4. a small mode Prague fiber Bragg grating (few-mode fiber Bragg grating, FM-FBG) is proposed and produced. The fiber carrier of FM-FBG only supports the transmission of two mode fields of LPo0 and LP11. Therefore, there is a pattern of self coupling peak and mode field mutual coupling peak in reflection and transmission spectra. The coupled mode equation is used to establish the analytical model of the grating and reveal the mode coupling process of FM-FBG, which provides a theoretical basis for further research and solving FM-FBG characteristic parameters. The influence of mode energy ratio, mode refractive index difference and coupling coefficient on the characteristics of resonant point intensity, bandwidth and wavelength interval in FM-FBG is found by simulation calculation in FMF. A dual wavelength tunable laser based on FM-FBG has been fabricated, and the spectral and hole burning (SHB) effect of EDF has been applied to realize the conversion of single wavelength to double wavelength. By using the filtering characteristic of LP01 self coupling transmission peak and the mutual transmission peak of LP01 and LPn in FM-FBG, the stable multitransverse mode output of single transverse mode output (base mode LP01) and LP01 and LP11 mixed mode are achieved in the online cavity structure.
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：TN253
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本文編號(hào)：1345433