Analysis on Mode Field Distribution of Waveguide Grating Coupler by the Scalar FDTD

The scalar two-dimensional finite difference time domain (FDTD) method is applied to simulate the mode field distribution of TE 0 of the waveguide grating coupler. Computer simulation shows that the same stable mode field distribution pattern is obtained through the different kinds of driving sources. It is found that the optical field mode is determined by waveguide structure and optical wavelength other than the driving source.According to the mode field distribution, the optimum coupling efficiency can be predicted. Compared with another numerical methods,the CPU-time and memory elements of computer used by FDTD are much less.

Tunable wavelength filters using polymer long-period waveguide gratings based on metal-cladding directly defined technique

In this work, long-period waveguide grating-based tunable wavelength filters using organic–inorganic grafting poly（methyl methacrylate）（PMMA） materials are designed and fabricated by metal-cladding directly defined technique.The thermal stabilities and optical properties of the organic–inorganic grafting PMMA core materials are analyzed. Structures and performance parameters of the waveguide gratings and self-electrode heaters are designed and simulated. The contrast of the filter is about 15 d B and the resonant wavelength can be tuned by different electric powers applied to the metal-cladding self-electrode heaters. The temperature sensitivity is 3.5 nm/℃ and the switching time is about 1 ms. The technique is very suitable for realizing the optoelectronic integrated wavelength-division-multiplexing systems.

High efficiency grating couplers based on shared process with CMOS MOSFETs

Grating couplers are widely investigated as coupling interfaces between silicon-on-insulator waveguides and optical fibers.In this work,a high-efficiency and complementary metal-oxide-semiconductor（CMOS） process compatible grating coupler is proposed.The poly-Si layer used as a gate in the CMOS metal-oxide-semiconductor field effect transistor（MOSFET） is combined with a normal fully etched grating coupler,which greatly enhances its coupling efficiency.With optimal structure parameters,a coupling efficiency can reach as high as ～ 70% at a wavelength of 1550 nm as indicated by simulation.From the angle of fabrication,all masks and etching steps are shared between MOSFETs and grating couplers,thereby making the high performance grating couplers easily integrated with CMOS circuits.Fabrication errors such as alignment shift are also simulated,showing that the device is quite tolerant in fabrication.

Demonstration of an As₂S₃Grating Coupler on Thin Film LiNbO₃

We present both design and experimental results for an As2S3 grating coupler on a thin film LiNbO3 substrate. A basic grating coupler structure is designed with coupling efficiency of 53% to a single mode fiber. A maximum simulated coupling efficiency of 78.8% is achieved, assuming a polymer bonding process. The basic structure was fabricated, and the coupling efficiency was measured to be at least 23.4% at 1540 nm. Some of the loss may be attributable to non-grating sources, such as waveguide tapers and testing fiber tails. A grating cavity was then measured using the grating couplers. The cavity waveguide propagation loss was 2.0 dB/cm. For a 400 nm thick As2S3 on 500 nm thin film LiNbO3 on insulator, the confinement factor in the LiNbO3 crystal is 82.3% when the As2S3 waveguide width is 400 nm, showing that As2S3-on-thin film LiNbO3 is an excellent candidate for thin film electro-optic applications.

A high-efficiency grating coupler between single-mode fiber and silicon-on-insulator waveguide

We present the design of a diffractive grating structure and get the optimal parameters which can achieve more than 75%coupling efficiency（CE） between single-mode fiber and silicon-on-insulator（SOI） waveguide through 2D finite-different time-domain（FDTD） simulation.The proposed architecture has a uniform structure with no bottom reflection element or silicon overlay.The structure,including grating couplers,adiabatic tapers and interconnection waveguides can be fabricated on the SOI waveguide with only a single electron-beam lithography（ICP） step,which is CMOS-compatible.A relatively high coupling efficiency of 47.2%was obtained at a wavelength of 1562 nm.

Highly Sensitive Refractive Index Sensor Based on Polymer Long-Period Waveguide Grating With Liquid Cladding

We propose a novel structure and unique sensing mechanism bio-chemical sensor which is fabricated by a polymer long-period waveguide grating with the detection liquid directly as the waveguide cladding.Quantitative detection is realized from analyzing the output absorption spectrum and resonant wavelength shift related to the liquid detection concentration.The proposed polymer long-period waveguide grating based liquid refractive-index sensor is developed experimentally,the high sensitivity of 1.01×10^4nm/RIU is achieved,and the temperature stability coefficient is 1.47nm/℃.Theoretically and experimentally,this work has been demonstrated to have potential application in chemical and biological detections and may provide an important technical support for solving today's increasingly serious civil problems such as food safety and drug safety, which will also have the important scientific significance and application prospects.

Analysis of Corrugated Long-Period Gratings in Planar Waveguides and Their Polarization Dependence

We present a theoretical analysis of corrugated long-period gratings in planar waveguides. In particular, we calculate the transmission spectra for both the TE and TM polarizations and highlight the polarization-independence conditions.

Tunable Filters Based on Cascaded Long-Period Polymer Waveguide Gratings

Long-period waveguide grating based filters have attracted attention due to their flexible fabrication,a variety of materials and structures,low back reflection,low insertion loss,and excellent performance in the tuning range and temperature sensitivity.To our knowledge,for the first time,a two-segment polymer long-period waveguide grating was cascaded to implement a filter with a narrower bandwidth.Experimental results showed that the device had a maximum extinction ratio of 24 dB at 1577 nm,and the 12 dB bandwidth was 10 nm.The temperature sensitivity of the fabricated device was 1.79 nm/℃.

基于铌酸锂薄膜波导的电光调谐光栅辅助定向耦合器研究

提出并实验研究了一种基于铌酸锂薄膜光波导的电光调谐的光栅辅助定向耦合器。该耦合器由单模与双模脊形波导及制作于双模波导侧壁的长周期光栅构成。长周期光栅的引入补偿了单模与双模波导中基模的相位失配,可在共振波长实现两波导中基模的高效耦合。进一步地,在双模脊形波导两侧制作调谐电极实现了高速、低驱动电压的电光调谐功能。优化了器件的制作工艺,并采用单次干法刻蚀将耦合器的光栅与波导同步制作于X切铌酸锂薄膜上。测试结果表明所制作的器件在1595.3 nm波长处实现了14.8 dB的隔离度,其电光调谐效率为0.38 nm/V(1595.3 nm~1599.0 nm),热光调谐效率为0.14 nm/℃(25℃~50℃)。该器件可用于实现可调谐滤波、滤模、电光调制及高灵敏度温度传感等功能。

硅基垂直光栅耦合器的研究进展

对国内外硅基垂直光栅耦合器的研究进展进行了总结,讨论了均匀光栅耦合器和非均匀光栅耦合器的研究现状,并对相关耦合器的性能参数做了对比和分析,为未来继续研发更高耦合效率、更大耦合带宽的垂直光栅耦合器提供思路与参考。

High-Q micro-ring resonators and grating couplers for silicon-on-insulator integrated photonic circuits

An ultra-small integrated photonic circuit has been proposed,which incorporates a high-quality-factor passive micro-ring resonator（MR） linked to a vertical grating coupler on a standard silicon-on-insulator（SOI） substrate.The experimental results demonstrate that the MR propagation loss is 0.532 dB/cm with a 10μm radius ring resonator,the intrinsic quality factor is as high as 202.000,the waveguide grating wavelength response curve is a 1 dB bandwidth of 40 nm at 1540 nm telecommunication wavelengths,and the measured fiber-to-fiber coupling loss is 10 dB.Furthermore,the resonator wavelength temperature dependence of the 450 nm wide micro-ring resonator is 54.1 pm/℃.Such vertical grating coupler and low loss MR-integrated components greatly promote a key element in biosensors and high-speed interconnect communication applications.

用MMI实现的平顶型AWG的特性分析

引入归一化偏移和归一化间距,利用高斯近似得到阵列波导光栅(AWG)的频谱响应,从而分 析了展宽系数、品质因数、插损与归一化间距的关系。给出一个实例,取归一化间距为0.707,对应的展宽系数约为2,插入损耗IL约为2dB,并用光束传输方法(BPM)进行了验证。

全息光聚合法制备聚合物波导光栅耦合器

在光通信及集成光学中,光波耦合器是关键器件之一。本文中选择树脂CN960E60单体作为聚合体系,采用自由基型对532nm波长敏感的单光子引发剂,利用全息光聚合法制备出聚合物波导光栅耦合器。在进行聚合实验之前,首先测定了聚合材料的透射光谱。实验观测结果证实了用光全息聚合方法制作波导光栅耦合器的可行性。

集成光学波导光栅研究进展

报道了20世纪80年代以来,研究组在集成光学波导光栅研究领域的主要工作及研究成果。其中包括集成光学波导光栅的制备研究;若干非线性波导光栅器件研究;高效体相位全息布拉格光栅-光导板的耦合互连;单片集成波导光栅波分复用等。这些研究工作为光通信、光计算、光传感和光学信息处理等应用领域提供小型化、低功耗、超快速全光型器件奠定了技术基础。

自聚焦平板波导透镜及其应用

介绍了一种新颖的自聚焦平板波导透镜(SPWL),利用几何光学方法分析了它的光学特性,得出其传输矩阵,并进行了特殊的结构设计。介绍了实际制备这种透镜的工艺过程,并给出了光纤输出光束经1/4节距的自聚焦平板波导透镜之后输出的近场和远场光斑图,测试结果表明自聚焦平板波导透镜输出近场光斑在 x-z 平面内束宽为1153.3 μm,与根据传输矩阵计算得出的束宽1153.2 μm相符;最后介绍了自聚焦平板波导透镜的三种应用实例:LD 阵列和光纤的耦合、SOA 与单模光纤的耦合、光功率分束器和直波导阵列波导光栅。

PDMS基光子器件的耦合光栅与波导研究

基于柔性材料聚二甲基硅氧烷(PDMS)的优异特性,面向紫外和可见光波段进行光子器件基础研究和设计。通过单模波导以消除模间传输损耗,基于布拉格条件的数值解析和有限元仿真优化设计耦合光栅结构,实现了光栅刻蚀比为0.9、周期为570 nm的峰值损耗为6 dB的单模波导集成型耦合光栅。结果表明,基于PDMS的芯片光子结构可以实现低损耗波导传输和高效波导光子获取。该工作为PDMS基柔性芯片光子集成器件奠定了理论和设计基础。

多孔硅-PMMA/DR1复合膜制备方法的研究(英文)

报道了用电化学腐蚀法结合激光干涉或聚合物掩膜制备多孔硅通道波导、定向耦合器、波导棱镜、光栅耦合器和激光诱导动态光栅等光子器件,并给出了这些多孔硅光波导器件的性能参数,研究结果表明可利用多孔硅开发出新的全硅光电子器件.

阵列波导光栅梳状带通滤波器的传输效率

在光波导模场分布高斯近似条件下,根据星形光波导耦合器的耦合特性,推导出了基于累加运算和卷积运算近似表达的阵列波导光栅梳状带通滤波器光谱响应效率的函数表达式。给出了阵列波导光栅梳状带通滤波器光谱响应效率曲线的半最大值全宽度和阵列波导光栅梳状带通滤波器的通道中心波长的光谱响应度与器件参数的关系。在输入信号光谱分布高斯近似条件下,给出了阵列波导光栅梳状带通滤波器信号通道传输效率的计算表达式和输入信号光谱宽度对阵列波导光栅梳状带通滤波器信号通道输出特性的影响。给出了物理意义明确的函数表达式,它们可为快速分析阵列波导光栅梳状带通滤波器的特性提供理论基础。

制备波导光栅的相位掩膜技术

制备波导光栅的相位掩膜技术＊马少杰李燕徐迈林久令（中国科学院长春物理研究所，长春１３００２１）（中国科学院激发态物理开放研究实验室，长春１３００２１）关键词光波导，光栅耦合器，全息光栅自从７０年Ｄａｋｓｓ等人首次报道了集成光波导光栅器件以来［１］，波...

氮化硅光子器件与应用研究进展

氮化硅材料提供了一种与CMOS兼容的集成光子平台,具有丰富的光学特性。通过调节相关制备参数,可以获得特定折射率的薄膜材料,且消光系数和非线性系数具有较大可调控范围。因此,氮化硅材料在薄膜光学、微纳平面光学、非线性集成光学等诸多领域具有广泛的应用前景。本文主要介绍氮化硅材料的光学特性及其在光学薄膜、微纳超构材料和硅光集成器件方面的研究现状,综述氮化硅材料在太阳能薄膜、可见光超构表面、光栅耦合器和非线性光波导等应用领域的研究概况。