Silica waveguide ring resonators with multi-turn structure

Optical waveguide ring resonator is the basic element of resonator integrated optic gyro (RIOG). In this paper, we report a novel configuration of optical waveguide ring resonator using a multi-turn structure. The characteristic of the light propagating across the crossed waveguides is analyzed using the finite difference beam propagation method. The relationship between the propagation loss and the intersection angle for arbitrary intersecting angles has been analyzed. Some crossed waveguides are fabricated in silica waveguides to verify the theoretical results. On this basis, the influences of the loop numbers and the excess loss of the crossed waveguide on the limited sensitivity of the RIOG have been analyzed. There is a critical intersection angle for certain resonator, only when the intersection angle is bigger than the critical angle, the gyro sensitivity can be improved by increasing the loop numbers. This will be helpful to how to determine the optimum length in resonator for its application in RIOG.     

谐振腔马赫-曾德尔干涉集成光波导陀螺

研究了光学环形腔中的单方向传输光在光学谐振腔中传输的情况，在系统旋转角速率变化时光束会产生频移，在此基础上，设计出一种具有谐振腔马赫-曾德尔干涉集成光波导陀螺结构，可以方便地检测出系统旋转角速率与方向，其检测精度与光波导谐振腔的品质无关。和萨尼亚克集成光波导陀螺相比较，性能价格比有进一步提高的潜力。     

一种基于金刚石多层波导结构微环谐振器的仿真分析

提出了一种以金刚石新型材料为芯层的单微环谐振器模型.谐振器的纵切面采用五层脊形波导结构,中间一层设定为金刚石,上下两侧分别是SiO_2和As_2S_3,即As_2S_3-SiO_2-金刚石-SiO_2-As_2S_3.设置操作波长为1550 nm,依据耦合膜理论和微环谐振理论,利用Comsol软件仿真模拟了单直波导纵切面、直波导和环形波导耦合区的纵切面以及微环在谐振波长为1543 nm时的场强分布,及直波导和环形波导耦合区间距改变时微环的场强分布和传输特性.在此基础上,依据传输矩阵法讨论了微环的品质因数、耦合系数变化对输出光谱的影响,并对微环损耗进行了讨论.结果表明:以金刚石为芯层的微环谐振器具有良好的光学特性,本结构在谐振波长为1543 nm时谐振峰值达到了-12 dB以上,品质因数达到了1.54×10~5,在耦合系数为0.01时,自由光谱范围约为40 nm.     

微型光波导陀螺中无源环形谐振器研究

光波导无源环形谐振器是微型光波导陀螺的核心敏感部件，其性能直接影响陀螺的极限分辨率和各误差项，是此种陀螺设计和制造中的关键。本文通过理论分析，对无源环形谐振器进行了深入的研究，提出了可行的光学系统设计，并结合现有先进的光学工艺，提出了加工与制造的方案。     

Magnetic plasmon mode resonance and power transmission in a nanosandwich waveguide

The magnetic plasmon (MP) modes in the metal-dielectric-metal nanosandwich structure are investigated nu-merically,and the principle of energy resonance in such a resonator is proposed.An equivalent inductance capacitance circuit analysis method is proposed and the results are in agreement with the numerical simulations.Based on the MP resonance in such a structure,a nanosandwich chain waveguide is designed.Gold and silver are chosen as the metal materials.The power transmission efficiency of the nanosandwich waveguide can be as high as 0.546 in a specific nanosandwich unit cell,even when the metal absorption loss is large,which is the perspective of the new waveguides and lasers based on MP modes.     

基于圆弧谐振腔的金属-介质-金属波导滤波器的数值研究

设计了一个基于圆弧谐振腔的金属-介质-金属波导滤波器, 并应用时域有限差分算法数值研究了它的传播特性. 结果发现, 在透射光谱中出现了明显的透射峰. 分析表明, 该透射峰是由表面等离极化激元在圆弧腔中的谐振所导致. 我们还研究了圆弧谐振腔的结构参数及其弯曲方向对其传播特性的影响. 此外, 该结构还可以用作一种光分路器, 实现滤波与分路的双重功能.     

利用离子交换技术制备跑道形波导谐振腔滤波器的研究

采用AgNO3和KNO3混和熔盐作为离子交换源,在K9玻璃上制备了跑道形波导谐振腔滤波器。利用ASE宽带光源和光谱仪对器件特性进行了测试,得到的该滤波器自由光谱范围为0.176nm。对比对Cr=4dB和3dB带宽δλ=0.13nm来说,耦合系数和传输损耗分别为к=0.9和α=3.2dB/cm。测试了环形腔的热光调相特性,在16℃的变化范围内实现了2π的相移。通过分析,波导材料的热光系数约为1.49×10-5/℃。该滤波器不仅可用于滤波、传感等领域,而且也可与其它波导结构相结合实现新的功能。     

耦合谐振器光波导旋转传感的相位灵敏度

利用光学谐振器结构的色散可提高旋转传感的灵敏度, 耦合谐振器光波导可实现强色散, 本文利用传输矩阵理论, 研究耦合谐振器光波导旋转传感的相位灵敏度, 讨论谐振器布局和波导参数对相位灵敏度的影响, 结果表明波导的相位曲线和相位灵敏度依赖于波导中谐振器的布局, 谐振器数量和耦合系数不仅会影响波导旋转传感相位灵敏度曲线峰值的数量和带宽, 还会影响相位灵敏度的大小, 而损耗会降低波导的相位灵敏度, 本文的结果可用于利用谐振器布局和波导参数设计耦合谐振器光波导的相位灵敏度, 对其在旋转传感方面的应用有重要意义. 关键词： 谐振器 旋转传感 光波导     

Analysis of a second-order polarization-independent filter made of a single ring resonator and a Sagnac interferometer

A novel second-order polarization-independent filter made of a single ring resonator and a Sagnac interferometer (SRRSI) is proposed, and its filtering characteristics are investigated. By using birefringence in waveguide, a single ring resonator can be used to synthesize a filter with second-order response. Analytical formulas are derived for characteristics of the SRRSI varied with waveguide parameters, such as the coupling coefficient; and the critical condition of a second-order Butterworth filter is given. The influence of loss in the ring resonator is also analyzed.     

用于集成光学陀螺的波导谐振腔设计

给出了一种集成光学陀螺谐振腔的优化设计方案,在保证集成光学陀螺精度的同时更利于微型化。选用传输损耗为0.01dB/cm的硅基二氧化硅材料作基底,谐振腔内损耗仅为0.5dB,保证了谐振腔的高清晰度;采用准单模矩形波导结构,利用弯曲波导对一阶模的有效限制实现了光的基模传输,利于谐振腔的小型化;分析了波导的传输损耗、波导耦合器分光比对谐振腔性能及陀螺极限灵敏度的影响,得出波导耦合器分光比的优化参数,并仿真得到谐振腔的谐振清晰度达到70以上。在激光器线宽为30kHz,探测器响应度0.95A/W,积分时间为10s的条件下,系统的极限灵敏度为1.6°/h。     

弯曲波导研究进展及其应用

本文主要分析了弯曲波导损耗机理,包括传输损耗、辐射损耗、模式转换损耗。重点综述了设计低损耗弯曲波导的方法,包括波导材料、弯曲波导的曲线形状、波导种类、脊型波导的宽度、脊高、弯曲半径、模场分布、弯曲波导曲线形状和其他新型波导结构等。简要概括了近年来设计和制备低损耗弯曲波导的代表性工作。介绍了弯曲波导在集成光学中的应用。通过对弯曲波导的损耗及耦合机制理论的不断完善,实现光在较小弯曲半径的低损耗传输,从而提高集成光学的集成度是弯曲波导今后的发展趋势。     

Defect assisted coupled resonator optical waveguide: Weak perturbations

Coupled resonator optical waveguides (CROW) comprised of only a few resonators including one defective element are investigated analytically and numerically. The defect is introduced by perturbing weakly the resonator at the center of the chain, creating a ‘cavity’ in what is an analogue of a Fabry-Pérot resonator or a defect-assisted photonic crystal structure. The device is found to have a very narrow resonance within the original stopband of the unperturbed CROW, and an accompanying extremely large group velocity excursion, that extends over both the subluminal and the superluminal ranges. The properties of the resonance and the magnitude of the group velocity dispersion are found to be conveniently controllable by coupling strength and by the number of resonators used. The perturbation can be caused thermo-optically or electro-optically. The complex effects of waveguide loss are extensively discussed.     

Efficient design of silicon slot waveguide optical modulator

An optimal design of a slot waveguide is presented for realizing an ultrafast optical modulator based on a 220 nm silicon wafer technology. The recipe is to maximize the confinement and interaction between optical power supported by the waveguide and electric field applied through metallic electrodes. As height of waveguide is fixed at 220 nm, the waveguide and slot width are optimized to maximize the confinement factor of optical power. Moreover, metal electrodes tend to make the waveguide lossy, their optimal placement is calculated to reduce the optical loss and enhance the voltage per unit width in the slot. Performance of an optimally designed slot waveguide with metal electrodes as ultrafast modulator is also discussed.     

表面等离激元在具有PT对称性的环谐振器中的传输

提出了具有PT对称性的金属-绝缘体-金属波导系统,由两个波导耦合一个环谐振器组成,环谐振器的上臂填充增益介质而下臂填充损耗介质。对表面等离激元在该系统的传输特性进行了研究,结果表明:通过平衡增益介质和损耗介质,PT对称性诱导的透明峰可以被清楚地看到,并且该透明峰具有反相位的特点。     

A photonic crystal side-coupled waveguide based on a high-quality-factor resonator array

Based on the present coupled mode theory of the photonic crystal resonator array in this paper,we propose a novel side-coupled waveguide to achieve highly efficient coupling of photonic crystal devices.It is found that the coupling efficiency is sensitive to the interval,the total number and the quality factor of the resonator.Considering the coupling efficiency and the coupling region,we select five resonators with an interval of six lattice periods.By optimizing the structure parameters of the waveguide and resonator,the quality factors of the resonator can be modulated and the coupling efficiency of the side-coupled waveguide reaches 95.47% in theory.Compared with other coupling methods,the side-coupled waveguide can realize efficient coupling with a compact structure,a high level of integration and a low degree of operational difficulties.     

微波频段表面等离子激元波导滤波器的实验研究

基于理论分析, 实验研究了二维磁单负材料/双正材料/磁单负材料表面等离子波导的滤波效应. 研究表明, 该波导结构具有低通滤波性质, 引入分支缺陷之后, 由于谐振效应该波导具有带阻滤波效应. 分支缺陷相当于亚波长谐振腔, 谐振腔的长度决定带阻滤波器的中心频率, 而中心频率几乎不受缺陷位置的影响; 滤波器透射率下降的幅度由耦合距离决定. 通过引入谐振腔及改变谐振腔的长度、数量以及耦合间距等参数, 可以实现可调节的表面等离子波导滤波器. 实验结果与理论分析符合得很好, 该性质将在可调的单通道或多通道带阻滤波器件中具有潜在的应用价值. 关键词： 表面等离子激元 特异材料波导 谐振腔 滤波器     

一种硅基SiO_2波导耦合器的设计与分析

波导耦合器是组成光纤传感系统和光纤通信系统光收发组件及模块的重要元器件,是实现光收发模块一体化光电集成的基础。给出了一种用光纤陀螺系统的X型四端口波导耦合器的工作原理,采用有效折射率法和BPM(Beam propagation method)法建立了耦合器的数学模型,计算并分析了耦合器尺寸在尽可能小的情况下和在满足单模传输的条件下耦合器的耦合系数、有效耦合长度、分光比以及回波损耗等参数之间的关系,并对其关键技术进行了系统的研究。仿真结果表明,所设计的波导耦合器在低损耗情况下分光比可达到50%∶50%,耦合器全长为33.5mm,输入输出波导间距为410μm,芯层截面积为6μm×6μm。     

Optimization of optical ring resonator devices for sensing applications

The Q-factor of an optical resonance device determines the width of its transmission resonances. For this reason, in sensing applications of optical resonators, it is commonly assumed that the Q-factor fully determines resonator sensitivity. Practically, the latter is not exactly correct. In this Letter, the parameters responsible for the sensitivity of resonance devices (i.e., the steepness and the sharpness of the transmission resonance) are analyzed. It is shown that, for given intrinsic losses of a single ring resonator sensor, the slope of the resonance is largest if its extinction ratio is 9.5 dB, while the resonance is sharpest if its extinction ratio is 6 dB. For a sensor consisting of several identical ring resonators coupled to a bus waveguide, the largest slope and sharpness parameters correspond to the extinction ratios of ~9 dB and ~4.5 dB, respectively. The determined optimum parameters can be achieved by tuning the coupling between the resonator rings and the waveguide.     

Nondestructive measurement of loss performance in channel waveguide devices with phase modulator

A novel method using a phase modulator is proposed for the nondestructive measurement of propagation loss in a channel waveguide. The phase modulator was fabricated on a Ti-diffused LiNbO3 crystal. Tuning the effective optical length of a waveguide by application of an electrical field on the phase modulator, the contrast of the resultant Fabry-Perot resonator in a channel waveguide device can be measured. The associated propagation attenuation coefficients are determined from the experimental results. Coordination of the phase modulator with an optical channel waveguide device not only allows measurement of the bending loss, but improvement in the relative intensity noise owing to the reduction of the reflected power.     

A photonic crystal side-coupled waveguide based on a high-quality-factor resonator array

Based on the present coupled mode theory of the photonic crystal resonator array in this paper, we propose a novel side-coupled waveguide to achieve highly efficient coupling of photonic crystal devices. It is found that the coupling efficiency is sensitive to the interval, the total number and the quality factor of the resonator. Considering the coupling efficiency and the coupling region, we select five resonators with an interval of six lattice periods. By optimizing the structure parameters of the waveguide and resonator, the quality factors of the resonator can be modulated and the coupling efficiency of the side-coupled waveguide reaches 95.47% in theory. Compared with other coupling methods, the side-coupled waveguide can realize efficient coupling with a compact structure, a high level of integration and a low degree of operational difficulties.