【作者】 赵爽；

【导师】 吴重庆；

【作者基本信息】 北京交通大学 ， 光学工程， 2010， 博士

【摘要】 全光触发器是数字光信号处理的基础技术之一,也是全光分组交换网的关键技术之一。本文对基于法布里-珀罗激光器、耦合环形激光器以及耦合偏振光开关等三种结构的全光触发器进行了深入的理论分析和实验研究,优化光触发器的分析方法,并研究了翻转时间、触发时间、触发光功率等一系列触发器的关键问题。据我们所知,本文首次对另一项全光信号处理技术——同步脉冲展宽技术进行了研究,提出利用光触发器和可调光延迟线实现可调脉宽的同步展宽方案。这些工作对于推进全光信号处理技术以及全光分组交换、全光路由、全光计算等领域的发展,都有重要的意义。本文取得的研究成果包括以下内容：1.提出了一种利用单个法布里-珀罗(FP)激光器实现全光触发器的结构。该结构使用两个波长不同的布拉格光纤光栅对FP的输出光进行反馈,使多纵模的F-P激光器只剩下两个竞争波长,从而实现了双波长稳态的光触发器；并利用自制的可调的温度稳定模块,实现了波长的稳定,波长漂移小于0.01nm。实验结果证实了该光触发器的技术可行性。这种方案具有结构简单、低成本、易集成等特点。2.针对基于两个互耦合的环形腔激光器所构成的全光触发器,首次应用解非线性方程的图解法来分析基于半导体光放大器(SOA)的光纤环形激光器(S-FRL)的振荡过程,从而确定了这种触发器的翻转时间。提出一种利用改变光纤环反馈系数来调节翻转时间的方法和一种增加外部注入光功率加速抑制激光过程的方法。3.通过图解法分析了耦合系数对于双环耦合双稳态触发器的影响,提出了一种通过合理配置耦合系数来优化该触发器的方法：耦合系数较小的端口应该用于构成环形谐振腔,耦合系数较大的端口应该用于抑制另外的激光器产生激光。通过实验证实了该方法的有效性。4.首次将邦加球分析法用于研究半导体光放大器(SOA)中的非线性偏振旋转(NPR)效应。提出了一个描述输出偏振态沿邦加球纬线旋转的方位角与SOA工作参数的简明表达式,指出SOA增益的相对变化量和线宽增强因子的偏振相关性是影响NPR的两个主要因素,简化了NPR的分析过程。分析了耦合偏振开关光触发器的触发特性和输出光信号的上升沿和下降沿,指出了在耦合偏振开关中,连接两个SOA的光纤长度决定了触发光脉冲的持续时间,同时也影响着触发器输出波形的上升沿和下降沿。5.提出了一种基于非线性光纤环路镜(NOLM:Nonlinear optical loop mirror)测量SOA中线宽增强因子的偏振相关性的方法,测量了不同输入光偏振态所对应的SOA线宽增强因子的具体数值,实验结果证实了该方法的有效性。6.提出了全光同步脉冲展宽的概念和一种实现方案,并具体使用光缓存器作为可调光延迟线,与双环耦合光触发器共同构成了同步脉冲展宽器,实现了将0.5μs光脉冲同步展宽到44μs和68μs。更多还原

【Abstract】 All-optical flip-flops (AOFF) are key devices for realizing many functionalities in optical networks and optical computing, especially as all-optical memories for the temporary storage of decisions in photonic packet routers. In this paper, we investigated three kinds of AOFFs theritically and experimentally. The conclusions of this paper are significant for the development of the all optical signal processing. The followings are some innovative works I have done:1. A novel optical flip-flop based on single Fabry-Perot Laser Diode (FP-LD) was proposed. Two Fiber Bragg Gratings with different wavelength were used to reflect the output power of the FP-LD, and make the FP-LD work under the bistability condition. This scheme is lower cost, easy for integration, and reduces the affect of wavelength fluctuation to the AOFF.2. The graphic method is proposed to analysis the Fiber Ring Laser (FRL) for the first time. The graphic method gets rid of complex calculations and is used to analyze the lasing and quenching process of the FRL. According to the Graphic Method, we obtain that the lasering and quenching process is influenced by the feedback factor of the FRL. The eternal inject optical power is also a key factor that influences the laser suppression, the bigger the power is and the shorter the laser suppress time is.3. The graphic method is used to analyze the bistability property of the coupled FRL. The important factor of the coupler structure to realize bi-stability is the couple split ratio between the two FRLs. The graphic method is also used to analyze the functional properties of the AOFF.4. The Poincare Sphere method is used to analyze the Nonlinear Polarization Rotation (NPR) effect of SOA for the first time. The PS method is applied to describe the variations of ellipticipy angle and azimuth of SOA output state of polarization (SOP) induced by polarization-dependent gain (PDG) and polarization-dependent phase shift, respectively. The theoretical results reveal that the polarization dependence of the linewidth enhancement factor (LEF) and the variation of SOA gain are significant factors for the NPR. The evolutions of output SOP on the PS under quasi-continuum condition have been demonstrated experimentally. This Poincare Sphere method has been used to optimazing the performance of AOFF based on polarization switch. 5. The polarization dependence of LEF has been measured for the first time. The result reveals that the polarization dependence of LEF plays an important roll in the NPR effect of SOA.6. The concept of synchronous pulse expanding has been proposed for the first time, which is an important technology for the optical packet switching network node. The synchronous pulse expanding scheme of AOFF cascaded with optical buffer has been demonstrated. In the experiment, the narrow input light with 0.5μs pulse width has been synchronously expanded to 44μs and 68μs respectively.更多还原