Investigation of the antenna characteristics with the impact of hexagonal metamaterial

Antenna miniaturization is a typical trend in contemporary wireless systems, notably for current wireless technology, to meet multiband needs while preserving high transmission qualities. The terahertz (THz) regime is helpful in advanced applications and significantly impacts wireless technology. This paper proposes a double-layered hexagonal split ring resonator (HSRR) based on a microstrip patch antenna (MPA) and analyzes the simulated characteristics. The HSRR width is varied for different thickness “w” values and compares the analysis of with and without HSRR in the antenna. Due to the impact of metamaterials, the optimized antenna produces −44.02-dB return loss, 1.012 voltage standing wave ratio (VSWR), 6.47-dBi gain, and 4.78-dB directivity at 1.8-THz frequency. This proposed antenna is suitable for THz applications, which include high-speed data rate in wireless communication, bio-medical field, and THz spectrometer.     

宽阻带三模谐振器微带带通滤波器设计

介绍了一种新颖的微带三模谐振器,由该谐振器构成的微带滤波器具有较宽的通带以及较好的带外抑制。对传统的单模微带环形谐振器结构进行优化,使谐振器在通带内具有三个谐振点,并且在通带边缘有四个对称衰减极点。引入的阶梯阻抗谐振单元使得微带三模谐振器具有良好的带外抑制。依据传输线原理对宽阻带三模谐振器进行了分析,并完成了中心频率为1090 MHz的宽阻带带通滤波器设计和加工,其实际测试结果与软件仿真结果具有良好的一致性。     

光纤环形复合谐振器的研究

介绍光纤环形复合谐振器的结构和工作原理，分析谐振器的参数对其特性的影响，并讨论其在各种领域的应用。     

一种新颖的复合环形谐振腔的理论分析

文章基于环形谐振腔所具有的非线性相位传输特性,提出了一种新型的动态光谱滤波器结构,它将全通环形谐振腔调相器接入平衡马赫-曾德干涉仪,实现复合结构的动态滤波特性.与传统的马赫-曾德干涉仪相比,此复合滤波结构可利用远小于π的相移调整实现输入光信号的开关,因此,在提高开关速度、降低调相器功耗等方面具有重要的应用价值.     

一种利用环形双模谐振器实现的带阻滤波器

提出了一种利用双模环形谐振器实现的带阻滤波器。该滤波器由一个对称的双模环形谐振器以及一段四分之一波长的平行耦合线组成。借助于在普通环形谐振器的两个相对边上添加一对小贴片,环形谐振器的两个简并谐振模式可以被可控的分离,从而可以构成带阻滤波器的工作频带。平行耦合线的作用是为了对双模谐振器进行馈电,同时也被用做两端口间的阻抗变换器。在理论分析之后,利用平面PCB工艺设计制作了滤波器样品,并对其进行了测量,进一步证明这种设计的有效性。     

全环形镜面利用的多程环形腔特性分析

本文分析了全环形镜面利用的多程环形腔的运行特性和输出特性。     

应用于THz波的非对称双开口环传输特性研究

设计并制备了一种适用于太赫兹波段的非对称双开口环结构,数值仿真和实验测量了其传输性质.结果表明,垂直极化时样品在低频的0.540 THz和0.925 THz处存在谐振点,来源于左右两开口环的LC谐振,电流和电场分布主要集中在两开口环的开口处;而在高频处(1.885THz)谐振点的表面电流具有相反的两个环流方向,电流和电场分布于整个样品表面,此处的谐振来源于两开口环耦合后的偶极子谐振.当太赫兹波平行极化该样品时,原来两个低频的LC谐振消失.实验测量结果与数值仿真具有很好的一致性.此结构超材料的传输特性研究对太赫兹波调制器、滤波器、吸收器及偏振器等器件设计和制备具有一定的指导意义.     

Efficient Method to Extract Coupling Ratio and Round-trip Loss Parameters of Optical Waveguide Ring Resonator

Based on the measurement of the contrast ratios of the transmission spectra from the throughput and drop ports of ring resonator, an efficient method is proposed to extract the coupling ratio and round-trip loss of the integrated optical waveguide ring resonator. The parameters of a racetrack resonator prepared by ion-exchange technique in K9 optical glass substrate are examined, which demonstrates the validity of this method. The accuracy and applicable range of this method are also discussed.     

调相谱检测技术下光纤环腔的谐振特性

调相谱检测技术是谐振式光学陀螺信号检测的重要手段。根据贝塞尔函数展开与光场叠加原理,理论分析了光纤环形谐振腔的传输特性;搭建了谐振特性测试系统,采用LiNbO3相位调制,针对不同调制频率与调制电压条件下光纤环的谐振特性和解调曲线特性开展了实验,对实验结果进行分析,得到了调制频率、调制电压与光纤环形谐振腔谐振信号及解调信号之间的关系,实验结果与理论分析相符;并对调制过程中出现的谷裂现象进行了测试与分析,通过实验数据拟合,得到了产生谷裂现象的临界调制频率与调制电压值之间的关系。     

Rapid and precise read-out of terahertz sensor by high-speed asynchronous optical sampling

High-speed asynchronous optical sampling is used for the rapid and precise determination of transmission resonances of terahertz surface sensors based on asymmetric double split ring resonator arrays. The sensor response represented by a characteristic resonant frequency is determined to 0.66113 THz with an accuracy of ±325 MHz within 2 seconds of read-out time.     

激光器线宽对光纤环形谐振腔谐振特性的影响

采用光波场叠加的方法计算了谐振腔光纤陀螺的核心敏感部件———光纤环形谐振腔 (FRR)的传递系数 ,详细分析了激光器光谱线宽对光纤环形谐振腔谐振特性的影响 ,并进一步分析了在一定激光器光谱线宽条件下 ,由光探测器散弹噪声所限制的谐振腔光纤陀螺极限灵敏度和光纤环形谐振腔光路参数之间的关系 ,从而为谐振腔光纤陀螺的优化设计提供了理论基础     

Electronic Feedback System for Stabilization of Fiber Ring Resonator

We propose a simple technique to stabilize the optical output intensity of a fiber ring resonator. The electronic feedback circuit system, which consists of two voltage control oscillators, a phase comparator, and a low pass filter, is applied to the fiber ring resonator in order to compensate the optical phase shift in the ring loop. The reference electrical signal determines the operating condition of the fiber ring resonator for the desired optical output signal. The experimental results within the operating range agree well with the analytical results. The simulated performance of the proposed model is also compared with that of other existing models and shows significant improvement over them.     

Tunable filters based on an SOI nano-wire waveguide micro ring resonator

Micro ring resonator(MRR) filters based on a silicon on insulator(SOI) nanowire waveguide are fabricated by electron beam photolithography(EBL) and inductive coupled plasma(ICP) etching technology.The cross-section size of the strip waveguides is 450×220 nm2,and the bending radius of the micro ring is around 5μm.The test results from the tunable filter based on a single ring show that the free spectral range(FSR) is 16.8 nm and the extinction ratio(ER) around the wavelength 1550 nm is 18.1 dB.After thermal tuning,the filter’s tuning bandwidth reaches 4.8 nm with a tuning efficiency of 0.12 nm/℃Meanwhile,we fabricated and studied multi-channel filters based on a single ring and a double ring.After measurement,we drew the following conclusions: during the signal transmission of multi-channel filters,crosstalk exists mainly among different transmission channels and are fairly distinct when there are signals input to add ports.     

有源光纤环形腔进行频率调谐窄线宽激光的方法

本文提出用有源光纤环形腔来获得精确调谐窄线宽激光的新方法，理论分析结果表明：幅值（或相位）调制产生的频宽扩展对腔带宽的影响很小，滤波输出激光的线宽约等于入射光随机初相位决定的线宽，有源腔对滤波输出激光还有光放大作用。     

多程环形腔失调引起的损耗分析

本文对多程环形腔失调引起的损耗进行了分析，导出了单程损耗的表示式，对这类腔的设计和调整有参考意义。     

二氧化硅光波导环形谐振腔

利用宽角光束传输法(WA-BPM)对二氧化硅平面波导环形谐振腔进行了优化设计,详细分析了不同环形腔长度下,谐振腔清晰度与环形腔耦合器耦合系数的关系,并进一步分析了由光探测器散弹噪声所限制的谐振型光学陀螺极限灵敏度和环形腔光路参量之间的关系。在此基础上,在硅衬底上利用火焰水解化学掺GeO2的二氧化硅波导上制作成带输入/输出耦合器的环形谐振腔芯片。并通过实验测试了所研制的光波导环形谐振腔,其清晰度高达60,理论分析表明采用上述环形谐振腔研制的陀螺,其极限灵敏度可达1°/h。     

Dynamic response of a fiber-optic ring resonator: Analysis with influences of light-source parameters

In practice, dynamic behavior of fiber-optic ring resonator (FORR) appears as a detrimental factor to influence the transmission response of the FORR. This paper presents dynamic response analysis of the FORR by considering phase modulation of the FORR loop and sinewave modulation of input signal applied to the FORR from a laser diode. The analysis investigates the influences of modulation frequency and amplitude modulation index of laser diode, loop delay time of the FORR, phase angle between FM and AM response of laser diode, and laser diode line-width on dynamic response of the FORR. The analysis shows that the transient response of the FORR strongly depends on the product of modulation frequency and loop delay time, coupling and transmission coefficients of the FORR. The analyses presented here may have applications in optical systems employing an FORR with a laser diode source.     

利用有机-无机溶胶-凝胶方法制备平面波导环形谐振腔

采用简单的有机-无机混合的溶胶-凝胶方法制备了折射率在一定范围内可调的波导材料,并利用其制备了平面波导环形谐振腔器件。波导结构呈现倒脊形,其制备工艺首先是利用感应耦合等离子体刻蚀技术(ICP)在二氧化硅衬底上刻蚀波导结构的凹槽,然后再沉积波导薄膜。利用光谱仪对器件的传输特性进行了测量,观测到具有10 dB对比度,自由光谱范围0.182 nm周期性谐振现象,结合环形谐振腔的传输特性,得到环形腔具有较低的传输损耗1.7 dB/cm。同时对环形谐振腔的温度特性进行了测量,得出波导材料的热光系数为-1.54×10-4/℃。     

四镜8字环形腔激光器的设计与实验研究

采用ABCD传输矩阵计算方法结合Matlab软件进行模拟计算,设计热稳定性良好的四镜8字环形激光谐振腔。该环形谐振腔在高功率泵浦条件下,腔模参数随热透镜焦距变化具有良好的稳定性。在腔内插入由法拉第旋光器和半波片组成的光学单向器,实现了单向运转。在泵浦功率为40 W时,获得最高功率为14 W的连续波单向1064 nm波长激光输出,光光转换效率为35%。     

有源光纤环形腔的频率滤波特性

本文首先从理论上通过简单的分析得以了有源光纤环形腔的输出谱密度函数公式，该式清楚地表明光纤环形腔的频率滤波特性。从该公式出发，详细分析了环形腔输入光纤宽和环形腔参数对输出光谱谱型和线宽的影响。最后，通过设计不同的环形腔的自由谱宽和不同线宽的激光器作为输出光源，对上述理论分析做了实验验证。理论和实验表明，由于环形腔的强度传递函数是多峰的响应函数，环形腔自由谱宽和输入激光线宽的大小直接影响到环形腔输出光频谱形状，即是单峰输出还是多峰输出，对于不同形状的光谱输出，输出激光的线宽受环形腔的参数影响也各不相同。