【作者】 朱宏娜；

【导师】 罗斌；

【作者基本信息】 西南交通大学 ， 通信与信息系统， 2013， 博士

【摘要】 光纤参量放大(FOPA)是一种基于光纤四波混频(FWM)效应的新型光放大技术,具有工作波长范围灵活、对信号的比特率和调制格式完全透明、高增益、大带宽、低噪声系数、高相敏特性等显著优点,并在全光信号处理方面具有广泛的应用,被认为是最适合未来超长距离密集波分复用系统(DWDM)和全光网络的光放大技术之一。因此,作为一种新型的光放大技术,光纤参量放大技术成为近年来新的研究热点。而如何提高并优化光纤参量放大过程的增益成为研究的重点。鉴于此,本论文围绕光纤参量放大过程中的光波调控的技术方法,致力于研究分析其对增益特性的影响。其目的是设计优化光纤参量放大过程增益的方案并从理论上和实验上对其进行深入研究。本文的主要研究内容和研究成果如下：深入研究了光纤参量放大过程的基本理论,概述了光纤参量放大过程的基本原理及主要结构,介绍了四波混频的基本机理,并在此基础上分别分析了单泵浦光纤参量放大过程和双泵浦光纤参量放大过程的理论模型,同时分别分析了他们在考虑泵浦消耗和不考虑泵浦消耗时的增益特性以及相位匹配条件,给出了不考虑泵浦消耗时的解析解,并分别搭建和研究了单泵浦结构和双泵浦结构的光纤参量放大实验系统。给出了采用光波调控方式的光纤参量放大过程的方案,在不考虑泵浦消耗时推导了基于光波调控技术的通用传输矩阵,给出了不考虑泵浦消耗时信号光的增益表达式,并通过仿真分析得到了增益的优化。应用标准G.652单模光纤(SSMF)与高非线性光纤(HNLF)级联,分别设计了单泵浦和双泵浦的光纤参量放大方案,理论分析了采用SSMF前后对系统增益的影响,并发现了梳状谱结构的增益谱；同时从实验上验证了采用SSMF级联时对光纤参量放大系统的影响。设计了对泵浦光进行相位控制的光纤参量放大系统的方案。利用传输矩阵法分析相移光栅的传输特性,应用泵浦光相移(PPS)的方法,实现了平坦化的系统增益；同时分析了通过相移光栅对泵浦光进行相移前后的光波的变化,结果表明：采用PPS后,相位失配得到了补偿,并且信号光的增益得到了提高；通过分析采用PPS前后的信号光的增益谱特性,获得了采用PPS后的更加平坦化的增益谱。提出了调控闲频光优化光纤参量放大过程增益的方案,分别对闲频光的相位和功率的调节两方面来优化系统的增益特性。提出了采用光滤波器抑制闲频光的单泵浦FOPA系统的结构,通过在两段HNLF间引入光滤波器,提高了信号光的增益和泵浦光向信号光的能量转换效率,并实现了增益带宽的优化。提出了利用相移光栅对闲频光同时移相和反射的系统结构,研究结果表明：引入相移光栅后,补偿了光波间的相对相位差和相位失配,从而提高了信号光的增益；并且,对比研究了相移光栅的反射率和相移量对信号光增益的影响作用。通过搭建实验系统,验证了采用均匀Bragg光栅(FBG)对闲频光的反射作用可以提高系统的增益,并且提高了泵浦光向信号光的能量转换效率。更多还原

【Abstract】 Fiber-optic parametric amplificatiaon (FOPA) is a new optical amplification technique based on four wave mixing (FWM), which has the obvious advantages of providing high gain uniform over a wide wavelength range, complete transparence to the signal bit rate and modulation formate, low noise figure, phase sensitivity, compatible with all fiber devices and so on. What is more, the FOPA has potentional advantages in all optical signal-processing, and it is considered as one of the most suitable optical amplifiable techniques for the future ultra-long-distance dense wavelength division multiplexing (DWDM) all-optial networks. Therefore, the FOPA has attracted increasing attencion recently as a new type of fiber optical amplifier. However, it is a very important issue to find some new ways of increasing and optimizing the gain spectrum of the FOPA. Considering the profound background, in this work, the lightwave regulation method is presented and concentrated on the influcnes to the gain properties of the FOPA, with the purpose of achieving the optimized gain method and investigating them deeply both from the theory and experiment. The main contents of the dissertation are as following.The basic theory of the FOPA is investigated comprehensively at first, as well as the main structure. And based on the principle of the FWM, the theory model is analyzed in the case of one-pump FOPA and two-pump FOPA, respectively, at the same time, both the signal gain without pump depletion and the gain with pump depletion are discussed. The phase matching condition and the analytical solution of signal gain without pump depletion are given for both the one-pump and two-pump cases. What is more, the amplification systems of both the one-pump FOPA and the two-pump FOPA are achieved experimently.The scheme of the FOPA based on lightwave regulation is presented and analized. Afer the derivation of the theory modle of the signal gain without pump depletion, the solution of the signal gain is given, meanwhile, the gain characteristics of the FOPA system is optimized obviously with the simulation and discussion.By using the standard single mode fiber (SSMF) connecting between two high nonlinear fibers (HNLFs), the cascaded systems of FOPA are designed. The SSMF is applied to compencate the phase mismatch parameter of the involed waves. The numerically simulation shows that the signal gain is increased and the gain bandwidth is broaded with the SSMF inserting between HNLFs, and the comb gain spectrum is observed. Furthermore, the amplification experimental flatform is set up and tested, and the result shows that the gain is improved, which is consistently with the simulation mentioned before.Next, the phase shifted fiber Bragg gratting (PS-FBG) is unilized to shift the phase of the pump wave in order to research the influence to the gain of FOPA. With the way of pump phase shifter (PPS), FOPA can gain flattened gain spectrum. In the case of the fixed signal wavelength, compareing with the system without inserting PPS, it can be seen that the phase matching is compensated and the signal gain is increased obviously with using PPS. On the other hand, the flat gain bandwidth is also abtainted by analyzing the gain spectrum.For the first time, the solution to enhance the efficiency of fiber optical parametric amplification is proposed by regulating the idler wave, and both the phase and the power properties of the idler wave are regulated. Firstly, the one-pump FOPA is designed by using an optical bandpass filter (OBPF) between two HNLFs to filter the idler wave, and it shows that both the signal gain and the pump-to-signal conversion efficiency are enhanced, with the gain flatter at the same time. Secondly, a PS-FBG is also adopted between two HNLFs to shift the phase and reflect the power of the idler wave during the amplification processing. The result shows that the phase mismatch is compensated, the relative phase difference of the involved waves is changed and the signal gain is improved clearly. Then influence of the reflectivity and phase shifter of the PS-FBG to the gain property are also discussed. At last, the experimental one-pump FOPA system via fiber Bragg grafting (FBG) reflecting the idler wave between two same HNLFs is constrocted and analyzed. The experimental results show that the sigal gain is increased, and the conversion efficiency of the pump power transferred to the signal power is enhanced synchronously.更多还原