本文選題：回音壁模式　切入點(diǎn)：光學(xué)諧振腔　出處：《中國(guó)科學(xué)技術(shù)大學(xué)》2016年博士論文　論文類型：學(xué)位論文

【摘要】：近年來(lái),回音壁模式(Whispering Gallery Mode, WGM)光學(xué)微腔因其極高的品質(zhì)因子(Quality factor,Q值)和極小的模式體積(V)得到了很大的關(guān)注,它們?cè)谥T多領(lǐng)域比如基礎(chǔ)物理理論研究以及實(shí)用化光電子器件(光開(kāi)關(guān)、光調(diào)制器、極窄線寬濾波器和高靈敏度傳感器等)領(lǐng)域都具有非常大的應(yīng)用潛力。盡管如此,目前它們基本還僅限于實(shí)驗(yàn)室研究,并沒(méi)有走向?qū)嵱没蛏唐坊：苤匾脑蚴荳GM的諧振特性受外界環(huán)境的影響非常大。首先,吸附到微腔表面的水汽或者微小灰塵顆粒會(huì)嚴(yán)重降低系統(tǒng)的Q值；其次,WGM的諧振波長(zhǎng)易受外界溫度變化的影響而產(chǎn)生偏移。這些都會(huì)導(dǎo)致基于微腔的傳感器的性能下降,并阻礙微腔的實(shí)用化。另外,為了獲得較高的耦合效率,通常使用錐形光纖來(lái)激發(fā)微腔中的諧振模式,這會(huì)導(dǎo)致整個(gè)耦合系統(tǒng)非常脆弱且缺乏健壯性,外部極小的振動(dòng)甚至微弱空氣流動(dòng)都可能引起WGM耦合狀態(tài)的顯著變化。以往的研究中,人們?cè)诜忾]的環(huán)境中進(jìn)行實(shí)驗(yàn),以保證微腔周邊干凈的環(huán)境以及穩(wěn)定的氣流。這種方式雖然可以極大限度的排除污染物的干擾以及溫度噪聲的影響,但巨大的密閉容器以及分立的耦合結(jié)構(gòu)使得整個(gè)系統(tǒng)非常笨重、復(fù)雜,不便于應(yīng)用在實(shí)際環(huán)境中。為了促進(jìn)微腔耦合系統(tǒng)的實(shí)用化,需要設(shè)計(jì)一種合適的封裝結(jié)構(gòu)。針對(duì)以上問(wèn)題,本論文提出了一些解決方案,論文內(nèi)容大體上可以分為兩大部分：理論仿真和實(shí)驗(yàn)。首先,利用FDTD方法以及COMSOL軟件的PDE求解器,研究了具有內(nèi)參考功能的三層結(jié)構(gòu)微球腔的耦合特性和傳感性能,仿真結(jié)果說(shuō)明我們提出的這種新型結(jié)構(gòu)的傳感器不僅能夠降低折射率傳感中的熱噪聲影響,還能同時(shí)探測(cè)溫度的變化。然后,我們實(shí)驗(yàn)研究了微球腔、柱形腔和瓶口腔的耦合特性,將它們封裝成為了一體化的器件,并進(jìn)行了溫度傳感實(shí)驗(yàn)以及抗振動(dòng)性能的測(cè)試。詳細(xì)的研究?jī)?nèi)容如下：(1)基于FDTD方法,實(shí)現(xiàn)了三層結(jié)構(gòu)微球腔與光波導(dǎo)耦合的仿真,三層膜的折射率從內(nèi)到外依次為高、低、高。研究了膜層厚度對(duì)諧振特性的影響,發(fā)現(xiàn)只要三個(gè)膜層所選擇的折射率以及厚度合適,內(nèi)外兩個(gè)高折射率膜層能夠束縛光波并支持它們各自的WGM。另外,我們還研究了微腔外的環(huán)境折射率變化對(duì)內(nèi)外層WGM諧振特性的影響,仿真結(jié)果說(shuō)明：環(huán)境折射率變化時(shí),外層模式的諧振波長(zhǎng)會(huì)顯著改變,但內(nèi)層模式的諧振波長(zhǎng)變化非常小,這個(gè)性質(zhì)使得三層結(jié)構(gòu)微腔在高精度折射率和溫度傳感領(lǐng)域有重要的應(yīng)用價(jià)值。(2)利用COMSOL軟件的弱解型偏微分方程模塊實(shí)現(xiàn)了微腔中諧振模式的穩(wěn)態(tài)仿真計(jì)算,并利用微擾理論,推導(dǎo)出了三層微腔的內(nèi)外層諧振模式用于溫度和折射率傳感的靈敏度表達(dá)式。我們發(fā)現(xiàn),內(nèi)外層兩模式的溫度響應(yīng)特性非常接近,但它們對(duì)外界折射率變化的響應(yīng)差異巨大。詳細(xì)研究了膜層厚度對(duì)內(nèi)外層模式的影響,通過(guò)優(yōu)化最外層的厚度,理論上實(shí)現(xiàn)了溫度噪聲的完美去除。(3)使用一種全新的封裝方案加工出了微腔與錐形光纖耦合系統(tǒng)的一體化器件,借助一個(gè)石英玻璃管、兩片石英玻璃以及紫外光固膠,在不改變己經(jīng)調(diào)諧好的耦合狀態(tài)的前提下完成了器件的封裝。實(shí)驗(yàn)中,讓微球腔與錐形光纖保持接觸,以提高耦合系統(tǒng)的穩(wěn)定性,這種情況下依然獲得了高達(dá)1.08x108的Q值。我們研究了微球腔取向和位置對(duì)諧振譜的影響,發(fā)現(xiàn)通過(guò)調(diào)整微球腔的位置以及取向可以獲得不同的諧振譜。將封裝器件密封在一個(gè)干凈的有機(jī)玻璃制作的盒子中,獲得了Q值的長(zhǎng)時(shí)間保持。另外,我們還制作了雙光纖耦合微球腔的封裝器件,可以應(yīng)用于Add-Drop濾波器,制作出的器件參數(shù)為：Q值達(dá)到2.7×10。,FSR約為0.016nm,最大Drop口輸出為42%。(4)通過(guò)光纖熔接機(jī)的電弧放電,我們制作出了高質(zhì)量的柱形腔和瓶口腔,在不同的耦合點(diǎn)實(shí)現(xiàn)了腔內(nèi)諧振模式的選擇性激發(fā)。在數(shù)值仿真以及理論計(jì)算的幫助下,獲得了諧振模式的空間場(chǎng)分布,實(shí)現(xiàn)了諧振模式的定位識(shí)別,與實(shí)驗(yàn)結(jié)果非常吻合。另外,通過(guò)軸向移動(dòng)微腔,實(shí)現(xiàn)了諧振模式的可控、穩(wěn)定的耦合。最后,我們采用與微球腔同樣的封裝方法,對(duì)柱形腔以及瓶口腔進(jìn)行了一體化封裝。由于柱形腔直徑的均勻性,模式場(chǎng)的分布在軸向上被顯著拉長(zhǎng),因此柱形腔封裝器件的抗振動(dòng)性能遠(yuǎn)遠(yuǎn)優(yōu)于微球腔器件。我們相信這種便攜的、具有良好健壯性的微腔器件將來(lái)會(huì)得到廣泛的應(yīng)用,尤其在振動(dòng)環(huán)境場(chǎng)合。
[Abstract]:In recent years, the echo wall mode (Whispering Gallery Mode, WGM) optical micro cavity because of its high quality factor (Quality, factor, Q) and the minimal volume model (V) has received much attention in many fields, such as the physical basis of their theoretical research and practical optoelectronic devices (optical switch, optical modulator. Narrow linewidth filter and high sensitivity sensor) field has great potential. However, they are only limited to present basic laboratory research, and there is no practical or commercial. An important reason is that the resonant characteristics of WGM influenced by the external environment is very large. First of all, the water vapor adsorption to micro cavity the surface or tiny dust particles would seriously reduce the Q value of the system; secondly, influence the resonant wavelength of WGM are vulnerable to external temperature changes and shifts. These will lead to the performance of sensor based on micro cavity Fall, and hinder the practicality of the micro cavity. In addition, in order to obtain high coupling efficiency, usually using tapered fiber to excite the resonant microcavity, which will lead to the whole coupling system is very weak and lack of robustness, minimal external vibration even weak air flow may cause significant changes in the WGM coupling state. In the past in the study, people were in a closed environment, in order to ensure the air cavity surrounding the environment clean and stable. Although this method can eliminate the maximum effect of pollutants and noise interference temperature, but the huge airtight container and a coupling structure of separation of the whole system is very cumbersome, complex, not easy to use in the actual environment. In order to promote the microcavity coupling system is practical, need to design a suitable package structure. To solve the above problems, this paper puts forward some solutions The content of the scheme, can be divided into two parts: theoretical simulation and experimental results. First, using the FDTD method and the PDE solver of COMSOL software, the coupling characteristics and sensing properties of the three layer structure of microsphere cavity with internal reference function, the simulation results show that the new sensor structure we propose not only to reduce the the refractive index of thermal noise in the sensor, but also detect the change of temperature. Then, we study the microsphere cavity, coupling characteristics of the cylindrical cavity and a bottle mouth, encapsulating them into an integrated device and a temperature sensing experiment and test of anti vibration performance. The detailed contents are as follows: (1) based on the FDTD method, the simulation of the three layer structure of microsphere cavity and waveguide coupling, three film refraction rate from the inside to the outside are high, low and high. On the film thickness on the resonant characteristic The influence of three, found that as long as the choice of film refractive index and thickness of the right, and two high refractive index film capable of binding light and support their WGM. in addition, we also study the micro cavity environment refraction rate changes influence on the resonant characteristics of inner and outer layer of WGM, the simulation results showed that the change of ambient refractive index when the resonant wavelength of outer model will change significantly, but the change of inner mode resonant wavelength is very small, this property makes the three layer structure of micro cavity has important application value in the high precision of refractive index and temperature sensing. (2) the use of COMSOL software for weak solutions of partial differential equations to achieve steady-state simulation of micro module the cavity resonance mode is calculated, and by using the perturbation theory, deduces the inner and outer layer of resonant modes for the sensitivity expression of refractive index and temperature sensing micro cavity three. We found that the inner and outer layer two mode temperature The degree of response is very close, but the difference of their response to external refractive index change is huge. The effects of thickness of inner layer pattern research in detail, through the optimization of the thickness of the outer layer, the theory to achieve the perfect temperature noise removal. (3) using a new package processing integration device of micro cavity with the tapered fiber coupling system, by means of a quartz glass tube, two pieces of quartz glass and UV curable adhesive, without changing the premise has been tuned coupling state under well finished package. In the experiment, let the microsphere cavity and the cone shaped fiber contact, in order to improve the stability of the coupling system, this kind of situation still get up to 1.08x108 Q. We study the orientation and position of microsphere cavity resonance spectrum, found by adjusting the position and orientation of the microsphere cavity can obtain different resonance spectrum. The package The sealing device in a clean organic glass box, the long time the Q value maintained. In addition, we also made the package double optical fiber coupling cavity, can be applied to the Add-Drop filter device parameters produced: Q value reached 2.7 * 10., FSR is about 0.016nm, the largest Drop output is 42%. (4) arc discharge by optical fiber fusion splicer, we produce high quality cylindrical cavity and a bottle mouth, at different coupling point to achieve the selective cavity resonance mode excitation. In the calculation of numerical simulation and theory under the help of the resonant mode field distribution is obtained to achieve recognition of resonant modes, in good agreement with the experimental results. In addition, the axial movement of micro cavity, the controllable resonant mode, stable coupling. Finally, we use the same and microsphere encapsulation method, the cylindrical cavity and mouth Cavity of a integrated package. Because the cylindrical cavity diameter uniformity, mode field distribution is significantly elongated in the axial direction, so the vibration resistance of cylindrical cavity package is far better than that of microsphere cavity devices. We believe that this kind of portable, microcavity device has good robustness will get extensive application. Especially in the environment of vibration occasions.

【學(xué)位授予單位】：中國(guó)科學(xué)技術(shù)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)：1564761