自適應非保偏—保偏光纖激光轉換技術研究
發(fā)布時間：2018-07-18 21:31
【摘要】：高功率、高亮度的線偏光纖激光在非線性頻率變換、引力波探測、激光通信、長距離傳感、光束合成等領域有著廣泛的應用。目前,獲得高功率高亮度的線偏激光主要采用基于保偏光纖以及偏振相關器件的保偏光纖激光器。在保偏光纖激光器中,受激布里淵散射、受激拉曼散射等非線性效應和模式不穩(wěn)定閾值要比同等條件下非保偏光纖激光器閾值低,保偏器件工藝復雜,價格昂貴,保偏光纖的切割、熔接等工藝難度較大。因此,一般而言,保偏光纖激光器輸出功率比非保偏光纖激光器的輸出功率低。為了獲得更高功率的線偏振光纖激光,本文提出了自適應非保偏—保偏激光轉換的技術方案,將非線偏振激光直接轉為高消光比的線偏振激光。論文對基于偏振控制器和鎖相控制原理的非保偏—保偏激光轉換的技術展開了詳細的理論和實驗研究,主要內(nèi)容包括:首先,介紹了保偏光纖激光器的發(fā)展現(xiàn)狀和功率限制因素,指出了自適應偏振轉換技術實現(xiàn)高功率保偏激光的可行性;回顧了國內(nèi)外研究人員在偏振控制領域的研究成果,總結了偏振控制技術在傳感、通信、光束合成等領域的發(fā)展現(xiàn)狀。其次,提出并設計了基于偏振控制器的自適應非保偏—保偏激光轉換控制系統(tǒng),開展了詳細的理論和實驗研究。理論上給出控制系統(tǒng)的基本結構和工作原理,建立了基于偏振控制器的偏振轉換系統(tǒng)的理論模型�；陔S機并行梯度下降算法,數(shù)值模擬了算法的增益系數(shù)和擾動精度、偏振控制器的控制精度和步進增益以及激光器穩(wěn)定性等因素對偏振轉換效果的影響。結果表明,通過優(yōu)化隨機并行梯度下降算法的參數(shù)以及偏振控制器的參數(shù)可以獲得高消光比的線偏振光。在理論研究的基礎上,搭建了基于偏振控制器的自適應轉換系統(tǒng)。根據(jù)系統(tǒng)的響應特性,改進了控制程序,分別進行了低功率種子光條件下和高功率放大器條件下的自適應偏振轉換。實驗結果表明:無論是非保偏的種子源還是高功率放大后的非保偏激光均可以利用偏振轉換技術實現(xiàn)高消光比的偏振轉換,此外,利用此結構可以對輸出光束進行任意角度的轉換輸出。然后,提出并研究了基于偏振鎖相的自適應轉換控制系統(tǒng)。理論上,給出了控制系統(tǒng)的基本結構和工作原理,建立了基于偏振鎖相的偏振轉換系統(tǒng)的理論模型,分析了系統(tǒng)的重疊誤差、傾斜誤差,閉環(huán)時的鎖相殘差以及合成光束的光強不同等因素對偏振轉換效果的影響。結果表明,系統(tǒng)重疊誤差與傾斜誤差通過在合成處的不重合與光能泄漏影響系統(tǒng)的轉換效率,重疊誤差會影響輸出的偏振度,但傾斜誤差并不影響輸出的偏振度。在鎖相殘差較小的情況下可忽略兩路光強不同對偏振度與轉換效率造成的影響,因此,鎖相殘差是影響系統(tǒng)合成效率與偏振度的關鍵因素。實驗上,分別搭建了全光纖結構與空間結構的基于鎖相控制的實驗平臺。在全光纖偏振轉換系統(tǒng)中,將非保偏的激光的消光比從5dB提高到了17.2dB。在空間結構系統(tǒng)中,最終獲得了偏振度為93.5%的高消光比激光。最后,提出了直接將高功率寬譜非保偏激光器輸出激光轉換為線偏振激光的方案。分析了方案的可行性,研究了在寬譜光源的條件下利用基于偏振鎖相的自適應轉換系統(tǒng)進行偏振轉換的可行性,并設計了初步的系統(tǒng)結構。本文通過理論和實驗研究提出了基于偏振控制和偏振鎖相非保偏—保偏光轉換技術方案的可行性,為實現(xiàn)高功率線偏振激光提供了一定的參考。
[Abstract]:High power, high brightness line biased fiber laser is widely used in nonlinear frequency conversion, gravitational wave detection, laser communication, long distance sensing, beam synthesis and other fields. At present, the polarization laser based on polarization maintaining fiber and polarization dependent optical fiber laser is mainly used to obtain high power and high brightness. In the device, the stimulated Brillouin scattering, the stimulated Raman scattering and other nonlinear effects and the mode instability threshold are lower than the non conservative fiber laser under the same condition, the process is complicated and the price is expensive, the cutting of polarization maintaining fiber and the fusion are more difficult. In general, the output power of the polarization maintaining fiber laser is not guaranteed to be biased. The output power of fiber laser is low. In order to obtain higher power line polarization optical fiber laser, this paper proposes an adaptive non polarization preserving polarization laser conversion technology. The non linearly polarized laser is directly converted to a linear polarization laser with high extinction ratio. The paper is a non conservative polarization laser conversion based on the polarization controller and the phase lock control principle. The detailed theoretical and experimental research is carried out. The main contents are as follows: first, the development status and power limiting factors of the polarization maintaining fiber laser are introduced. The feasibility of the adaptive polarization conversion technology to realize high power polarization maintaining laser is pointed out, and the research results of researchers at home and abroad in the field of polarization control are reviewed and summarized. The development status of polarization control technology in sensing, communication, beam synthesis and other fields. Secondly, an adaptive non conservative partial polarization maintaining laser conversion control system based on polarization controller is proposed and designed. The detailed theoretical and experimental research is carried out. The basic structure and working principle of the control system are given in theory, and the polarization control based on polarization control is established. The theoretical model of the polarization conversion system. Based on the stochastic parallel gradient descent algorithm, the influence of the gain and disturbance accuracy of the algorithm, the control precision and the step gain of the polarization controller and the stability of the laser on the polarization conversion effect are numerically simulated. The results show that the parameter of the random parallel gradient descent algorithm is optimized. The parameters of the polarization controller can obtain the linear polarized light with high extinction ratio. On the basis of the theoretical study, an adaptive conversion system based on the polarization controller is built. According to the response characteristics of the system, the control program is improved, and the adaptive polarization rotation under the condition of low power seed light and high power amplifier is carried out respectively. The experimental results show that the polarization conversion of high extinction ratio can be achieved by the polarization conversion technology, both of the non conservative seed source and the non conservative laser after the high power amplification. In addition, the output beam can be converted at any angle by using this structure. Then, the adaptive rotation based on polarization phase locking is proposed and studied. In theory, the basic structure and working principle of the control system are given, and the theoretical model of polarization conversion system based on polarization locked phase is set up. The influence of the overlap error, the tilt error, the phase locked residual of the closed loop and the different light intensity of the synthetic beam on the polarization conversion effect is analyzed. The overlapping error and the tilt error affect the conversion efficiency of the system by the non coincidence and light leakage at the synthetic place, and the overlap error will affect the degree of polarization of the output, but the tilt error does not affect the degree of polarization of the output. The influence of the intensity and conversion efficiency of two different light intensity can be ignored in the case of the small phase locked residual difference. Phase locked residual is the key factor affecting the efficiency and degree of polarization of the system. In the experiment, the experimental platform based on phase locked control of all fiber structure and space structure is set up respectively. In all fiber polarization conversion system, the extinction ratio of the unbiased laser is increased from 5dB to 17.2dB. in the spatial structure system, and the polarization is finally obtained. A high extinction ratio laser with a degree of 93.5% is presented. Finally, a scheme to convert the output laser of a high power wide spectrum non conservative laser to a linearly polarized laser is proposed. The feasibility of the scheme is analyzed. The feasibility of the polarization conversion based on the polarization locked phase adaptive conversion system under the condition of wide spectrum light source is studied and the preliminary design is made. In this paper, the feasibility of the scheme based on polarization control and polarization locked polarization - Polarization - preserving - polarization conversion is proposed through theoretical and experimental research, which provides a certain reference for high power linear polarization laser.
【學位授予單位】：國防科學技術大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TN248
本文編號：2132830
[Abstract]:High power, high brightness line biased fiber laser is widely used in nonlinear frequency conversion, gravitational wave detection, laser communication, long distance sensing, beam synthesis and other fields. At present, the polarization laser based on polarization maintaining fiber and polarization dependent optical fiber laser is mainly used to obtain high power and high brightness. In the device, the stimulated Brillouin scattering, the stimulated Raman scattering and other nonlinear effects and the mode instability threshold are lower than the non conservative fiber laser under the same condition, the process is complicated and the price is expensive, the cutting of polarization maintaining fiber and the fusion are more difficult. In general, the output power of the polarization maintaining fiber laser is not guaranteed to be biased. The output power of fiber laser is low. In order to obtain higher power line polarization optical fiber laser, this paper proposes an adaptive non polarization preserving polarization laser conversion technology. The non linearly polarized laser is directly converted to a linear polarization laser with high extinction ratio. The paper is a non conservative polarization laser conversion based on the polarization controller and the phase lock control principle. The detailed theoretical and experimental research is carried out. The main contents are as follows: first, the development status and power limiting factors of the polarization maintaining fiber laser are introduced. The feasibility of the adaptive polarization conversion technology to realize high power polarization maintaining laser is pointed out, and the research results of researchers at home and abroad in the field of polarization control are reviewed and summarized. The development status of polarization control technology in sensing, communication, beam synthesis and other fields. Secondly, an adaptive non conservative partial polarization maintaining laser conversion control system based on polarization controller is proposed and designed. The detailed theoretical and experimental research is carried out. The basic structure and working principle of the control system are given in theory, and the polarization control based on polarization control is established. The theoretical model of the polarization conversion system. Based on the stochastic parallel gradient descent algorithm, the influence of the gain and disturbance accuracy of the algorithm, the control precision and the step gain of the polarization controller and the stability of the laser on the polarization conversion effect are numerically simulated. The results show that the parameter of the random parallel gradient descent algorithm is optimized. The parameters of the polarization controller can obtain the linear polarized light with high extinction ratio. On the basis of the theoretical study, an adaptive conversion system based on the polarization controller is built. According to the response characteristics of the system, the control program is improved, and the adaptive polarization rotation under the condition of low power seed light and high power amplifier is carried out respectively. The experimental results show that the polarization conversion of high extinction ratio can be achieved by the polarization conversion technology, both of the non conservative seed source and the non conservative laser after the high power amplification. In addition, the output beam can be converted at any angle by using this structure. Then, the adaptive rotation based on polarization phase locking is proposed and studied. In theory, the basic structure and working principle of the control system are given, and the theoretical model of polarization conversion system based on polarization locked phase is set up. The influence of the overlap error, the tilt error, the phase locked residual of the closed loop and the different light intensity of the synthetic beam on the polarization conversion effect is analyzed. The overlapping error and the tilt error affect the conversion efficiency of the system by the non coincidence and light leakage at the synthetic place, and the overlap error will affect the degree of polarization of the output, but the tilt error does not affect the degree of polarization of the output. The influence of the intensity and conversion efficiency of two different light intensity can be ignored in the case of the small phase locked residual difference. Phase locked residual is the key factor affecting the efficiency and degree of polarization of the system. In the experiment, the experimental platform based on phase locked control of all fiber structure and space structure is set up respectively. In all fiber polarization conversion system, the extinction ratio of the unbiased laser is increased from 5dB to 17.2dB. in the spatial structure system, and the polarization is finally obtained. A high extinction ratio laser with a degree of 93.5% is presented. Finally, a scheme to convert the output laser of a high power wide spectrum non conservative laser to a linearly polarized laser is proposed. The feasibility of the scheme is analyzed. The feasibility of the polarization conversion based on the polarization locked phase adaptive conversion system under the condition of wide spectrum light source is studied and the preliminary design is made. In this paper, the feasibility of the scheme based on polarization control and polarization locked polarization - Polarization - preserving - polarization conversion is proposed through theoretical and experimental research, which provides a certain reference for high power linear polarization laser.
【學位授予單位】：國防科學技術大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TN248
【參考文獻】
相關期刊論文 前6條
1 張曉青;賈豫東;董建晶;;分布式光纖傳感雙通道調(diào)制光源設計與測試[J];激光技術;2015年03期
2 黃智蒙;唐選;劉倉理;李劍峰;張大勇;王小軍;韓梅;;變增益隨機并行梯度下降算法及其在相干合成中的應用[J];中國激光;2015年04期
3 王小林;張漢偉;于海龍;陶汝茂;周樸;郭少鋒;許曉軍;陳金寶;;3.15kW全光纖單模激光器[J];中國激光;2015年02期
4 黃龍;馬鵬飛;陶汝茂;史塵;王小林;周樸;;1.5kW全光纖線偏振激光器[J];強激光與粒子束;2015年01期
5 陶汝茂;周樸;王小林;司磊;劉澤金;;高功率全光纖結構主振蕩功率放大器中模式不穩(wěn)定現(xiàn)象的實驗研究[J];物理學報;2014年08期
6 陶汝茂;王小林;肖虎;周樸;劉澤金;;高功率光纖放大器中模式不穩(wěn)定閾值功率的理論研究[J];光學學報;2014年01期
相關博士學位論文 前1條
1 黃智蒙;光纖激光主動相位與偏振自適應控制技術研究[D];中國工程物理研究院;2014年
相關碩士學位論文 前1條
1 熊玉朋;光纖放大器的偏振自適應控制技術研究[D];國防科學技術大學;2012年
，本文編號：2132830
本文鏈接：http://sikaile.net/kejilunwen/dianzigongchenglunwen/2132830.html
教材專著
