【作者】 郭永娟；

【导师】 孙军强；

【作者基本信息】 华中科技大学 ， 光学工程， 2006， 硕士

【摘要】 本文首先介绍了未来光通信网络中的核心器件之一——全光波长转换器(AOWC),介绍了全光网络中对AOWC的基本要求,进而讨论了基于半导体激光器、半导体光放大器、非线性光纤环镜的全光波长转换器,分析了各种全光波长转换器的优缺点以及国内外研究近况。在此基础上提出了本文所研究的全光波长转换器——基于非线性光波导周期极化反转铌酸锂(PPLN)的和频与差频级联型二阶非线性效应的全光波长转换器,主要研究有:理论研究:首先给出了非线性极化的弹簧模型,形象的说明了非线性极化强度的产生原理;然后从麦克斯韦方程组和物质方程出发,经过简单的近似推导出和频与差频级联型全光波长转换的瞬态耦合波方程;最后介绍了该波长转换中的关键技术——准相位匹配技术(QPM),并将其与双折射相位匹配技术进行了比较,进而更加明确了准相位匹配技术的优点。数值模拟:首先计算了和频与差频级联型全光波长转换技术在波矢失配量的允许范围内,准相位匹配波长允许的范围。分别计算了该波长转换技术在脉冲泵浦和连续泵浦情况下:转换效率随着PPLN长度的变换曲线;泵浦光功率、两束泵浦光之间的间距、泵浦光的脉冲宽度以及走离效应对转换效率的影响;计算了信号光和转换光的可调谐范围;并计算了转换光脉冲宽度随着信号光没冲宽度的变化曲线。实验研究:由掺铒光纤放大器、偏振控制器、PPLN、耦合器、可调窄带滤波器和可调衰减器组成的可调谐的光纤环形腔激光器产生的连续光作为泵浦光,40Gbit/s的可调谐脉冲光作为信号光进行了实验。测量了和频与差频级联型全光波长转换的转换效率,对其信号光以及转换光的可调谐性进行了测量,并测量了该波长转换的稳定性以及3dB带宽。更多还原

【Abstract】 First, Introduced one of the core devices in future optical networks——All- optical wavelength converter(AOWC), analyzed the based requirements of the AOWC. Then discussed several Introduced several kinds of all-optical wavelength converter based on Semiconductor Lasers, Semiconductor Optical Amplifier and Nonlinear Optical Loop Mirror. Then put forward the AOWC studied in this paper——the wavelength conversion based on the cascaded sum- and difference frequency generation (SFG+DFG) in quasi-phase- matched (QPM) periodically poled LiNbO3 (PPLN) waveguides, The main contents are as follows:Theory study: First put forward the spring-model of the nonlinear polarization, which showed the principle of the polarization visually. Then educed the nonlinear instantaneous coupling-wave equation of the cascaded sum- and difference frequency generation begin with the Maxwell and the Physical equations. Last, discussed the key technology in the PPLN——quasi-phase-matched (QPM), and compared with the birefraction, and analyzed the advantages of the QPM.Numerical simulations: First calculated the range of the QPM wavelength of the cascaded sum- and difference frequency generation, which empowered in the range of the phase mismatch. Then did some calculations of the wavelength conversion under pulse-pump and continuum-pump: Calculated the evolutions of the conversion efficiency with the PPLN; Analyzed the effect to the wavelength conversion by the pump wave power, the space between the two pump waves, the width of the pump and the depart of the waves; Calculated the tunable range of the signal wave and generated wave; And calculated the pulse-width of the generated wave.Experiment study: The pump waves were the continuous light produced by the tunable fiber ring laser, which constituted by the EDFA, PC, PPLN, coupling devices, tunable filters and tunable attenuator, and the signal wave was the tunable pulsed laser, the velocity of which was 40Gbit/s. Measured the conversion efficiency of the wavelength conversion based on the cascaded sum- and difference frequency generation; Checkout the tunabity of the signal wave and generated wave; Measured the 3dB width of the pump, and the stability of the wavelength conversion.更多还原