本文選題：部分相干光　切入點(diǎn)：相位調(diào)制　出處：《西安電子科技大學(xué)》2014年碩士論文

【摘要】：相干光在傳輸過(guò)程中受大氣的影響退化為部分相干光;同時(shí)部分相干光的大氣傳輸特性可以有效抑制湍流帶來(lái)的光強(qiáng)閃爍、相位起伏等影響。近幾年激光雷達(dá)研究的熱點(diǎn)之一的新體制激光符合成像雷達(dá),正是要用具有部分相干光特性的激光作為發(fā)射光源。因此,研究部分相干光的產(chǎn)生方法是很必要的。采用激光照射到旋轉(zhuǎn)毛玻璃形成的動(dòng)態(tài)散斑作為部分相干光源是如今最常用的產(chǎn)生方法,可行性高且系統(tǒng)成本較低,但毛玻璃的存在會(huì)大大降低激光輸出功率;激光器諧振腔內(nèi)調(diào)制產(chǎn)生部分相干光的系統(tǒng)較為復(fù)雜,且成本相對(duì)較高;基于液晶空間光調(diào)制器的部分相干光方案也受限于輸出功率和調(diào)制速度等因素。因此開(kāi)展可產(chǎn)生高功率輸出、相干性可控和可快速預(yù)置光場(chǎng)的部分相干光的研究,具有重要的學(xué)術(shù)意義和應(yīng)用價(jià)值。本文基于陣列光束合成和部分相干光理論,從理論和實(shí)驗(yàn)的角度分別對(duì)光纖陣列產(chǎn)生部分相干光系統(tǒng)的方案進(jìn)行驗(yàn)證。首先介紹了光的相干性理論,然后分別闡述了光的時(shí)間相干性,空間相干性和部分相干性。介紹了一種典型部分相干光的數(shù)學(xué)模型,并從關(guān)聯(lián)性角度來(lái)描述其光場(chǎng)的相干性,簡(jiǎn)單描述了光場(chǎng)的高階相關(guān)理論,并通過(guò)光的強(qiáng)度關(guān)聯(lián)系數(shù)來(lái)為后續(xù)測(cè)試部分相干光相干長(zhǎng)度做出理論鋪墊�；诠馐铣衫碚�,研究了不同模型,不同間距,不同附加隨機(jī)相位抖動(dòng)方差下的光場(chǎng)強(qiáng)度分布的數(shù)值仿真,為后續(xù)實(shí)驗(yàn)系統(tǒng)改進(jìn)和實(shí)驗(yàn)測(cè)試提供理論依據(jù)。利用鈮酸鋰相位型調(diào)制器、平面波導(dǎo)(PLC)光纖分路器和光纖陣列基板(FA)設(shè)計(jì)和改進(jìn)了實(shí)驗(yàn)室搭建的部分相干光的方案。采用實(shí)驗(yàn)室開(kāi)發(fā)的基于FPGA的相位調(diào)制器驅(qū)動(dòng)電路可為相位調(diào)制器提供最高10MHz,±5V的模擬電壓輸出。利用光纖陣列部分相干光產(chǎn)生系統(tǒng)對(duì)部分相干合成后的光強(qiáng)分布與空間相干性進(jìn)行了實(shí)驗(yàn)測(cè)試,通過(guò)驅(qū)動(dòng)電路系統(tǒng)加載不同范圍均勻隨機(jī)電壓,可使強(qiáng)度關(guān)聯(lián)系數(shù)在1~1.48范圍內(nèi)可控。通過(guò)實(shí)驗(yàn)結(jié)果測(cè)試與理論仿真對(duì)比,驗(yàn)證了方案可行性。
[Abstract]:The atmospheric effect of coherent light is reduced to partially coherent light, and the atmospheric propagation characteristics of partially coherent light can effectively suppress the effects of turbulence, such as intensity scintillation and phase fluctuation.In recent years, one of the hotspots of lidar, laser coincidence imaging radar, is to use laser with partial coherent light as the emitting light source.Therefore, it is necessary to study the generation method of partially coherent light.The dynamic speckle produced by laser irradiation to the rotating glass is the most commonly used generation method nowadays, which has high feasibility and low system cost, but the laser output power will be greatly reduced by the existence of the ground glass.The system of laser resonator modulation to produce partially coherent light is complex and the cost is relatively high. The partially coherent light scheme based on liquid crystal spatial light modulator is also limited by the output power and modulation speed.Therefore, the research of partially coherent light which can produce high power output, coherence controllable and fast preset light field has important academic significance and application value.Based on the theory of array beam synthesis and partially coherent light, the scheme of optical fiber array generating partially coherent optical system is verified theoretically and experimentally in this paper.Firstly, the coherence theory of light is introduced, and then the temporal coherence, spatial coherence and partial coherence of light are described respectively.In this paper, a mathematical model of a typical partially coherent light is introduced, and the coherence of the light field is described from the angle of correlation, and the high order correlation theory of the light field is briefly described.The correlation coefficient of light intensity is used to lay a theoretical foundation for the subsequent measurement of coherent length of partially coherent light.Based on the theory of beam synthesis, the numerical simulation of intensity distribution of light field with different models, different spacing and different variance of additional random phase jitter is studied, which provides a theoretical basis for the improvement of the experimental system and the experimental test.Using lithium niobate phase modulator, planar waveguide PLC fiber splitter and fiber array substrate FAA), the scheme of partially coherent light in laboratory is designed and improved.The phase modulator drive circuit based on FPGA developed in laboratory can provide the analog voltage output of up to 10 MHz and 鹵5 V for the phase modulator.The optical intensity distribution and spatial coherence after partial coherent combination are experimentally tested using partially coherent optical fiber array optical generation system. The uniform random voltages with different ranges are loaded through the drive circuit system.The strength correlation coefficient can be controlled in the range of 1 ~ 1.48.The feasibility of the scheme is verified by comparing the experimental results with the theoretical simulation.
【學(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TN958.98

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相關(guān)期刊論文 前1條

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本文編號(hào)：1724388