基于软光刻的高聚物多模光功率分配器

设计并制作了一种紧凑型高聚物光功率分配器,该器件长度比传统器件结构缩短近1/3,实现了器件的微型化改进.利用设计仿真工具BeamProp对器件所需参量进行详细的筛选分析,最终确定了器件结构的具体数值.采用极具优势的软光刻技术印制成功高聚物1×8光功率分配器,在实际的测量中所得损耗结果与模拟仿真符合较好.该器件很大程度上迎合了通信器件微型化的发展趋势,且所采用的制作工艺具有加工便捷,成型快速,成本低廉等独特优势,使器件的规模生产成为可能.     

利用硅波导实现全混洗变换的新方法

全混洗变换在光互连中具有重要的作用.本文提出并实现了一种新的全混洗变换实现方法——硅波导实现全混洗变化.分析了全混洗变化的基本理论及其特点;利用软件OptiFDTD仿真并分析了4×4和8×8的PS变换结构;根据仿真结果,利用感应耦合等离子体刻蚀等工艺对SOI基片进行加工,制作了基于硅基的片上全混洗变换结构.结果显示,该结构的传输效率在80%以上,而且此结构的串扰在1%左右,该结构具有传输效率高,插入损耗和串扰较低等特点,并且在结构上具有体积小、结构简单、易于集成等优点,将在未来的光学集成及光学计算机中发挥重要作用.     

基于软光刻的多层光互连垂直耦合结构

设计并试制了一种新型垂直耦合光互连线路结构,可用于高速计算机内部等垂直堆叠的多层连通光互连的芯片间光信息通讯。其结构简单,且具有较小的连接损耗(可低至0.05dB)。对四种不同的典型波导截面(分别为30μm×30μm,50μm×50μm,100μm×100μm,200μm×200μm),利用蒙特卡罗多光线追迹分析法对跨越1~6层的垂直耦合结构进行了性能分析,发现当该结构的跨越高度与横向跨越距离的比值约为0.128时,可实现较理想的低损耗(低于1dB)光传输。采用软光刻的方法制备了实验多层光互连线路,其性能测试与理论结果基本相符。     

半导体激光阵列谱合束系统中光束串扰物理机制分析

在外腔反馈半导体激光谱合束系统中,由于半导体激光阵列的“smile”效应、外腔中光学元件制作误差等因素,激光阵列一子单元发射光束经过外腔返回注入其他子单元,在两子单元之间形成光束串扰并影响合束特性.本文从耦合腔光束谐振角度出发,基于光反馈半导体激光器速率方程,构建了耦合腔谐振模型,推导了激光器稳态输出时能在耦合腔中起振的光束模式.结合耦合腔模式竞争机制与耦合腔谐振模型分析由两子单元间距变化引起的不同串扰对锁定光谱和合束效率的影响.结果表明子单元间的串扰行为会造成光谱峰值下降、光谱偏移、边缘毛刺以及合束效率劣化.相比距离更远的两子单元之间的高阶串扰,距离更近的两子单元间的低阶串扰对合束特性的劣化程度更大.最后,为证明该模型的正确性和有效性,对所得分析结果进行了实验验证,实验观测到在串扰影响下的光谱结构与理论分析一致.     

一种硅基金属狭缝表面等离子体波导的设计

设计了一种适用于光电子集成电路的表面等离子体波导结构.利用三维全矢量时域有限差分法对该波导结构进行了数值模拟,并分析了其在基模传输时的模式场分布与金属结构顶角的关系以及其能量限制性.研究了该波导结构在不同金属材料下的有效折射率和传播长度对芯层宽度的依赖关系,讨论了两个该波导结构之间的耦合长度、最大转移功率和彼此间的串扰.结果表明:光场被高度限制在芯层区域,在金属结构顶角为135°时,其能量限制因子更高;在金属材料确定的情况下,有效折射率随芯层宽度增大而减小,而传播长度增大;在芯层宽度一定的条件下,两个波导结构间的耦合长度随波导间距增大而增大,最大转移功率和串扰随波导间距增大而减小.     

一种基于纳米级CMOS工艺的互连线串扰RLC解析模型

基于纳米级CMOS工艺,综合考虑电容耦合与电感耦合效应,提出了分布式RLC耦合互连解析模型.采用函数逼近理论与降阶技术,在斜阶跃输入信号下提出了受扰线远端的数值表达式. 基于90和65 nm CMOS工艺,对不同的互连耦合尺寸下的分布式RLC串扰解析模型和Hspice仿真结果进行了比较,误差绝对值都在4%内,能应用于纳米级片上系统（SOC）的电子设计自动化（EDA）设计和集成电路优化设计. 关键词： 纳米级CMOS 互连串扰 分布式 RLC解析模型')" href="#">RLC解析模型     

空间交叉波导耦合特性分析

由两根在空间呈X型放置的光波导组成的空间交叉波导结构是构成垂直耦合光分束器、垂直耦合光滤波器、垂直耦合光开关和垂直耦合上/下复用器等三维集成光学器件的基本结构单元.提出用一种等效模场匹配法分析空间交叉波导耦合特性,将矩形波导的场分布看成是对圆对称光纤场分布的微扰,解决了对角区场分布的表达,从而计算空间交叉波导的耦合长度,并用三维全矢量光束传输法验证了分析结果.将两种方法所得的空间交叉波导耦合长度加以比较,最大误差为1.2%,平均误差为0.9%.结果表明该等效模场匹配法具有精度高、运算速度快等优点,为基于空间交叉波导的三维集成光学器件的设计和分析提供理论基础.     

一种定向耦合器型高聚物光开关设计

本文提出了一种基于定向耦合器型的高分子聚合物波导光开关设计,其突出特点是极低的波长相关性和耦合区几何尺寸敏感度,可采用橡胶成型工艺(Rubber Molding Process)实现高聚物波导在硅基底上的快速转印成型.利用BPM方法进行了器件的波导结构设计及性能模拟,插入损耗为0.4-0.6 dB,串扰<-32 dB,偏振相关损耗约为0.08 dB,电光系数r33＝14 pm/V时,器件的开关电压为42 V.     

光致变色多阶光存储中的光学串扰分析

利用光致变色材料的灰度分阶特性可以实现多阶光存储。以傅里叶光学和光致变色记录符的可叠加性为基础,采用霍普金斯标量衍射理论的经典归-化坐标,对光致变色多阶光存储中的光学串扰进行了理论建模和数值分析。作为后续电通道补偿设计的前提。数值计算结果表明：相邻记录符与盘基信号的交叉串扰项是光学串扰的主要成分,且随着中心距的增加,相邻记录符引起的串扰迅速降低;当无寻道误差时,邻道记录符引起的串扰可以忽略;高阶记录符引起串扰要明显高于低阶的串扰。且影响多阶存储的可分阶性;实验结果很好地验证了所建立的模型的合理性。     

一种基于纳米级CMOS工艺的互连线串扰RLC解析模型

基于纳米级CMOS工艺,综合考虑电容耦合与电感耦合效应,提出了分布式RLC耦合互连解析模型.采用函数逼近理论与降阶技术,在斜阶跃输入信号下提出了受扰线远端的数值表达式. 基于90和65 nm CMOS工艺,对不同的互连耦合尺寸下的分布式RLC串扰解析模型和Hspice仿真结果进行了比较,误差绝对值都在4%内,能应用于纳米级片上系统(SOC)的电子设计自动化(EDA)设计和集成电路优化设计.     

Sub-microns period grating couplers fabricated by silicon mold

This paper describes a novel simple process suitable for fabrication of micro-periodic structure in optical waveguide. The mold was fabricated using electron beam lithography and fast atom beam etching. Sub-micron-scale patterns were transferred from silicon mold to polymer layer. Grating coupler was fabricated by the mold and normal optical mask. In the proposed method, no press which is needed for imprint lithography is required and the mold structure can be duplicated with high aspect ratio. Experimental coupling efficiency is about 25%. This technique can also be used to fabricate other nanometer-scale structures.     

Polymer-waveguide-based vertical coupler

A 2 × 2 polymer-waveguide-based vertical coupler was designed and fabricated. The relationships between the coupling efficiency and the key optical design parameters of vertical coupler (such as the crossing angle, gap thickness between two waveguide layers and the waveguide dimensions) were investigated by using beam propagation method. Based on these simulations, a fully polymer vertical coupler was demonstrated.     

Controlled waveguide coupling for photon emission from colloidal PbS quantum dot using tunable microcavity made of optical polymer and silicon

A tunable microcavity device composed of optical polymer and Si with a colloidal quantum dot (QD) is proposed as a single-photon source for planar optical circuit. Cavity size is controlled by electrostatic micromachine behavior with the air bridge structure to tune timing of photon injection into optical waveguide from QD. Three-dimensional positioning of a QD in the cavity structure is available using a nanohole on Si processed by scanning probe microscope lithography. We fabricated the prototype microcavity with PbS-QD-mixed polymenthyl methacrylate on a SOI (semiconductor-on-insulator) substrate to show the tunability of cavity size as the shift of emission peak wavelength of QD ensemble.     

电光聚合物波导中的锥形结构

提出并设计了一种基于电光聚合物的锥形波导,可用于单模光纤与电光聚合物波导器件之间的连接.锥形波导中采用了宽度锥形和折射率锥形结构.宽度锥形采用劈形形状,通过宽度和折射率的缓慢变化实现模场转换.劈形形状的宽度锥形具有较小的损耗且易于制作,折射率锥形可采用灰度掩膜光刻技术制作.研究了锥形波导的传输损耗与锥形波导的长度、波导宽度和厚度、材料吸收损耗等参数的关系及其优化,分析了锥形波导中的功率传输、模场分布与模式转换效率.结果显示锥形波导的传输损耗小于0.37 dB,光纤-波导-光纤的连接损耗优于1.62 dB,对插入损耗的改善达到8.78 dB,模场转换效率达到了83.7%.     

Single etch grating couplers for mass fabrication with DUV lithography

Surface grating couplers enable efficient coupling of light between optical fibers and planar waveguide circuits. While traditional grating designs require two etch steps for efficient coupling to silicon-on-insulator waveguides, recently proposed subwavelength structured gratings can achieve the same coupling efficiencies with a single etch step, thereby significantly reducing fabrication complexity. Here we demonstrate that such couplers can be fabricated on a large scale with ultra-violet lithography, achieving a 5?dB coupling efficiency at 1,550?nm. Through both simulations and experiments we give physical insight on how pattern fidelity impacts the performance of these couplers, and propose strategies to deal with inevitable process variations.     

Photonic band-gap enhanced second-harmonic generation in a planar lithium niobate waveguide

Enhanced second-harmonic generation (SHG) conversion efficiency was theoretically predicted in waveguide geometry with coupling to a one-dimensional grating photonic band gap (PBG). We report a series of experiments using samples made with lithium niobate. A waveguide was fabricated near the surface by applying the proton-exchange technique. The characteristics of waveguide modes were determined by several techniques: prism coupling, diffraction, and Cherenkov radiation. The WKB method was used to analyze the results. Ultraviolet laser lithography was applied to make PBG gratings on the sample. We further investigated Cherenkov second-harmonic generation (CSHG), i.e., SHG radiated into the substrate, under the condition of a band-edge PBG resonance in the waveguides. The SHG inside planar waveguides was also experimentally investigated. We fabricated waveguides with multiple pump modes and found that the second mode was more efficient in enhancing the second harmonic signal. This result is explained by our model. Several samples were investigated in detail; the highest conversion efficiency of CSHG with a PBG was enhanced around 50 times above the CSHG signal without a PBG. A numerical model was constructed with parameters calculated from our sample characterization data to interpret the experimental results.     

Circular grating coupler for creating focused azimuthally and radially polarized beams

We show a planar optical circuit design that takes light from an input waveguide and creates a focused azimuthally or radially polarized beam emanating from the surface of the substrate. It is implemented in silicon-on-insulator waveguides and does not require any external components to focus the beam. The focal spot size can be subwavelength and is potentially useful for lithography, imaging, optical data storage, optical trapping, optical excitation of molecules, or coupling to optical fibers.     

Design and analysis of a low loss and large-tolerance optical interface for large-area optical waveguides

An alternative interface structure design of a large-area optical waveguide for a large-area optical printed circuit board using a step-out fabrication technique is proposed. To investigate the misalignment tolerances and coupling excess losses, we simulated and compared our proposed structure to a typical straight core structure. As a result, the proposed structure was found to significantly improve the misalignment tolerance by more than 2 times and successfully conduct a data-link based on large area optical waveguide of 50 cm ×?50 cm.     

Babinet-Inverted Optical Nanoantenna Analogue of Electromagnetically Induced Transparency

A Babinet-inverted optical nanoantenna analogue of electromagnetically induced transparency based on the coupling between two magnetic dipole antennas and a magnetic octupole antenna in a Au film waveguide is demonstrated. Simulation results indicate that a pronounced elimination occurs in the radiating spectrum due to the coupling-induced radiation suppression. A two-oscillator electromagnetically induced transparency model is used to describe the antenna. The coupling coefficient between the magnetic dipole antennas and the magnetic octupole antenna is calculated using the model and is found to decline exponentially with the increase of the distance between them. Such an antenna can be directly integrated with optical waveguides or transmission lines,thus is of fundamental significance for the applications in nano-optics, such as the optical device miniaturizations and photonic circuit integrations.     

跑道型结构光子晶体波导定向耦合器

鉴于波导定向耦合器在集成光路以及光电集成方面的广泛应用,提出了一种基于光子晶体波导间高效耦合的光子晶体定向耦合器。通过主波导和耦合波导间的耦合,可以实现对波长为1 490 nm和1 550 nm电磁波的高效分光。在将器件长度控制在30 μm左右的同时,其总效率高达93.05%。另外,发现主波导和耦合波导间介质柱结构参数对电磁波的耦合周期有着极大的影响。并通过将介质柱沿z方向拉伸0.1a(a为晶格周期),设计了工作波长为1 530 nm和1 540 nm的光子晶体定向耦合器,器件长度仅为60 μm。通过拉伸介质柱的纵向长度,可以大幅减小耦合周期,这对缩小器件体积以及实现更为密集的波分复用有着重要的意义。