【作者】 刘鑫；

【导师】 孔梅；

【作者基本信息】 长春理工大学 ， 光学， 2013， 博士

【摘要】 近几年来,利用微环谐振器实现光速控制已成为光子学领域的一个研究热点。微环谐振器可以通过结构设计而产生谐振增强,从而实现大的色散,得到明显的光速控制效果。但是利用带有损耗的单微环谐振器实现光速控制时,存在的问题是在临界耦合点附近有强烈的光损耗和严重的脉冲畸变。在耦合双环谐振器中能实现类似于原子气体中的电磁诱导透明效应的耦合谐振器诱导透明现象,同时伴有相对于单环更大的色散,可实现显著的快、慢光。本文以光速控制为主要应用目的,以引入增益作为改善光速控制效果的辅助手段,对带有损耗或增益的耦合双环谐振器的传输和色散特性做了全面系统的分析。全文研究内容和研究成果可以总结为以下几个方面：1、研究了单环和耦合双环谐振器的基本传输特性。基于单环和耦合双环谐振器的传递函数,分析给出了它们在不同耦合条件下有效相移的主要特征。对耦合双环谐振器,指出可以按照透射率极值点的数量划分其透射谱类型,给出了极值点满足的方程。2、系统地研究和揭示了包括带有增益情况在内的耦合双环谐振器的传输特性。推导了带有增益的单环和耦合双环谐振器的激光阈值。基于带有损耗和增益的微环谐振器的对称性,首次对带有增益的耦合双环谐振器的透射谱类型进行了分析,指出其可呈现特有的倒置的耦合谐振器诱导透明(ICRIT)和吸收(ICRIA)谱,给出了透射谱类型划分判据。按谐振点和分裂点透射率的大小关系,系统完整地分析了透射谱类型与参数条件的对应关系。按不同增益和损耗情况下群延迟的表达式,分析了各种情况下的快、慢光条件,与透射谱类型产生条件结合,完整地给出了不同参数条件下的光谱类型和快、慢光情况。3、系统地研究和揭示了结构参数对耦合双环谐振器传输特性的影响规律。通过全面分析微环谐振器的群延迟和透射率对透射系数和振幅传递系数的导数,研究了不同参数范围下透射系数和振幅传递因子对群延迟和透射率的影响。结合产生模式分裂情况下产生快、慢光的参数条件,详细地给出了利用微环谐振器实现光速控制时的综合的性能-参数关系。演示了如何针对特定的设计目标,利用这一性能-参数关系进行优化设计。定义了耦合双环谐振器群速度控制的工作带宽,分析了影响工作带宽的因素。4、分析了单环和耦合双环谐振器中高阶色散对输出脉冲的影响。通过计算无损耗无增益的微环谐振器的入射脉冲在三阶色散极值点和二阶色散极值点的输出脉冲,揭示了二阶和三阶色散对微环谐振器中脉冲传输的作用。发现并分析了随着入射光脉冲中心波长远离谐振波长,输出脉冲分裂逐渐变浅直至消失的现象,以及快光输出时分裂出现在脉冲后沿,慢光输出时分裂出现在脉冲前沿的现象。5、搭建了光纤环透射谱实验测试装置,完成了单环和双环透射谱的实验测试,测得了双环中的耦合谐振器诱导透明效应。本文工作系统地揭示了耦合双环谐振器的透射特性和色散特性、器件参数对传输特性的影响以及高阶色散对微环谐振器输出脉冲的影响,研究成果为该结构微环谐振器在光速控制上的应用,以及其滤波和色散特性的其它应用提供了坚实的理论基础和设计优化依据。更多还原

【Abstract】 Recently, group velocity control of light by microring resonators has been one of hot research areas in photonics field. Resonance can be enhanced in microring resonators through structure design, and large dispersion and significant group velocity can be realized. However, using lossy microring resonators to realize fast or slow light often suffers serious attenuation and great distortion near the critical point. As the EIT effect in atomic vapor, EIT-like effect referred to as coupled-resonator-induced transparency (CRIT) exists in coupled double-ring resonators (CDRRs), which is often accompanied by greater dispersion than single microring resonators and can realize obvious slow and fast light.In this dissertation, taking the group velocity control of light as the main application goal and introducing gain as an assistant means to improve the effect of the group velocity control, we researched the characteristics of transmission and dispersion in coupled double-ring resonators with loss or gain comprehensively. In summary, major research contents and achievements are as the following:1. The transmission characteristics of single and coupled double-ring resonators were studied. Based on the transfer functions of the single and coupled double-ring resonators, the major characteristics of their effective phase shifts at different conditions were provided. For the CDRRs, we pointed out that the classification of the transmittance response can be distinguished according to the number of its extreme points, and the equation satisfied by the extreme points was given.2. The transmission characteristics of CDRRs including those with gain are investigated systematically. The lasing thresholds of gain structures were provided. For the first time, based on the symmetry between the transmission characteristics of two coupled double-ring resonators with symmetrical loss and gain, the transmittance and dispersion characteristics of CDRRs with gain are analyzed systematically. We pointed out that their transmittance spectra may appear as specific inversed CRIT (ICRIT) and CRIA (ICRIA) and criteria for different transmittance spectrum types were given. According to the relative relation between the transmittances at resonance and at the split modes, the corresponding relation between parameter conditions and types of transmission spectra was analyzed comprehensively. According to expression of group delay under different loss or gain, the conditions of slow and fast light in various situations were analyzed. Combining the conditions for different types of the transmittance spectra, conditions for types of the transmittance spectra and slow/fast light were provided completely.3. The influence of structure parameters on CDRR group delay and transmittance were investigated systematically. Through finding derivatives of CDRR group delay and transmittance with respect to the coupling coefficients and amplitude transmission factors, the effect of these parameters on group delay and transmittance at different conditions were found. Combing the parameter conditions for fast or slow light when mode splitting appears, comprehensive performance-parameter relations for group velocity control are provided. We showed for a specific design goal how to use these performance-parameter relations to carry out design and optimization. Moreover, the working bandwidth of group velocity control realized by a CDRR was defined and the factors affecting the working bandwidth were analyzed.4. The effects of higher order dispersion on output pulse in single and coupled double-ring resonators were analyzed. Through calculating the pulse response of microring resonators without loss/gain to incident pulses at the extreme value point of the second-and third-order dispersion respectively, the effect of the second-and third-order dispersion on output pulse were revealed. We found that as the pulse center wavelength of the incident pulse departing from the resonant wavelength, the splitting bottom of the output pulse became shallow gradually until disappeared. In addition, for slow light the splitting occurs at front part of the pulse, and for fast light it appears at the back part.5. An experimental system for transmittance spectrum measuring was developed. The transmittance spectra of single and coupled double-ring fiber resonators were measured. The CRIT effect spectra in coupled double-ring fiber resonators were realized.In this dissertation the transmittance and dispersion characteristics of CDRRs were demonstrated. The influence of the structure parameters on the transmission characteristics of CDRR, and the effect of higher order dispersion on output pulse in microring resonators were analyzed systematically. Work in this dissertation provides a solid theory foundation and design basis for applications of CDRRs on group velocity control and others based on its transmittance and dispersion performance.更多还原