本文關(guān)鍵詞：簡易帶隙型光子晶體光纖的傳感應(yīng)用研究　出處：《中國計量學(xué)院》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 簡易帶隙型光子晶體光纖 模式干涉 揮發(fā)性有機物 雙錐級聯(lián)

【摘要】：簡易帶隙型光子晶體光纖是一種新型光子晶體光纖,與普通的光子晶體光纖相比,它具有較高的占空比與更寬的通頻帶寬,此外,由于其特殊的結(jié)構(gòu)使得纖芯基模與包層模之間的耦合會被有效抑制。本論文研究了兩種基于此光纖的模式干涉結(jié)構(gòu),并利用其較大占空比的結(jié)構(gòu)特點進行揮發(fā)性有機物傳感檢測;同時為了實現(xiàn)基于簡易帶隙型光子晶體光纖錐形模式干涉結(jié)構(gòu),本文提出了一種基于CO2激光器的新型光纖拉錐技術(shù)。具體研究內(nèi)容如下:1、提出并實現(xiàn)了兩種基于簡易帶隙型光子晶體光纖的模式干涉結(jié)構(gòu),一種將其與單模光纖進行坍塌熔接,另一種則將揮發(fā)性有機物分子擴散進光纖空氣孔內(nèi);與前者相比,基于揮發(fā)性有機物分子擴散的模式干涉光傳輸損耗小,且無需繁雜的塌陷熔接步驟。此外,還利用有限元法建立簡易帶隙型光子晶體光纖的理論模型,對其在不同環(huán)境下的模場進行分析,所得的理論分析與實驗數(shù)據(jù)相符。2、提出并實現(xiàn)了一種基于簡易帶隙型光子晶體光纖內(nèi)瑞利散射原理進行揮發(fā)性有機物的傳感測量。將簡易帶隙型光子晶體光纖與單模光纖機械對準而不熔接,使得揮發(fā)性有機物分子經(jīng)擴散作用進入光纖空氣孔內(nèi),由于瑞利散射發(fā)生較大傳輸損耗,導(dǎo)致輸出光強降低。揮發(fā)性有機物濃度越高,進入空氣孔的揮發(fā)性有機物分子越多,由瑞利散射引起的傳輸損耗也越大。通過監(jiān)測輸出光的強度可實現(xiàn)對揮發(fā)性有機物濃度的傳感測量。經(jīng)實驗驗證,當簡易帶隙型光子晶體光纖長度為51 mm時,對乙醇的傳感測量靈敏度為0.22 d B/ppm。3、提出了一種基于CO2激光器的新型光纖拉錐系統(tǒng),并成功制作出基于單模光纖的雙錐級聯(lián)干涉儀,并進行相關(guān)物理量的傳感測量。經(jīng)實驗驗證,僅當兩個級聯(lián)錐區(qū)的直徑不同時干涉峰最明顯;當曲率變化為6.48-7.98 m-1時;其靈敏度可達到-25.946 nm/m-1;角度變化為0.02o-0.0375o時傳感器的靈敏度為601.8 nm/o;溫度變化為20-110℃對應(yīng)的靈敏度為0.09 nm/℃,折射率變化為1.3394-1.422對應(yīng)的靈敏度為36.3 nm/RIU。可見該干涉儀可對微小的彎曲、角度變化進行傳感測量,且不易受到外界環(huán)境、溫度的影響。進一步地,我們使用該系統(tǒng)制作出基于簡易帶隙型光子晶體光纖的雙錐級聯(lián)干涉儀,并對其傳感特性進行了初步研究。
[Abstract]:Simple bandgap photonic crystal fiber is a new type of photonic crystal fiber. Compared with ordinary photonic crystal fiber, it has higher duty cycle and wider bandwidth. Because of its special structure, the coupling between core mode and cladding mode can be effectively suppressed. In this paper, two kinds of mode interference structures based on this fiber are studied. The volatile organic compounds (VOCs) were detected by using the structure characteristics of large duty cycle. In order to realize the conical mode interference structure based on simple bandgap photonic crystal fiber, a new fiber tapered technique based on CO2 laser is proposed in this paper. The specific research contents are as follows: 1. Two kinds of mode interference structures based on simple bandgap photonic crystal fiber are proposed and realized, one is to collapse and weld it to a single mode fiber, the other is to diffuse volatile organic compounds into the air hole of the fiber. Compared with the former, the interference light transmission loss based on VOC molecular diffusion is less, and there is no complicated collapse fusion step. A simple theoretical model of bandgap photonic crystal fiber is established by finite element method, and the mode field in different environments is analyzed. The theoretical analysis is in agreement with the experimental data. 2. Based on the principle of Rayleigh scattering in a simple bandgap photonic crystal fiber, the sensing measurement of volatile organic compounds is proposed and realized. The simple bandgap photonic crystal fiber is mechanically aligned with the single-mode fiber without welding. Because of the large transmission loss of Rayleigh scattering, the output light intensity decreases, and the higher the concentration of volatile organic compounds, the higher the concentration of volatile organic compounds. The more VOC molecules enter the air pore, the greater the transport loss caused by Rayleigh scattering. The sensor measurement of VOC concentration can be realized by monitoring the intensity of output light. When the length of the simple bandgap photonic crystal fiber is 51 mm, the sensing sensitivity for ethanol is 0.22 dB / ppm.3. A new fiber taper pulling system based on CO2 laser is proposed, and the double cone cascade interferometer based on single mode fiber is successfully fabricated, and the sensing measurement of related physical quantities is carried out. Only when the diameter of the two cascaded cones is different, the interference peak is most obvious. When the curvature change is 6.48-7.98 m ~ (-1); Its sensitivity can reach -25.946 nm / m ~ (-1); The sensitivity of the sensor is 601.8 nm / o when the angle is 0.02o-0.0375o; The sensitivity corresponding to the temperature variation of 20-110 鈩，

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