InGaAsP的折射率色散及其波导的单膜尺寸

理论分析了红外光波导开关中波导层Ｉｎ_（１－ｘ）Ｇａ_ｘＡｓ_ｙＰ_（１－ｙ）的折射率色散，对波长为１．３μｍ的激光，当ｙ＝０．４０，ｘ＝０．１８时，波导层的折射率为３．３８；当ｙ＝０．００，ｘ＝１．００时，其折射率为３．２１。数值计算得到矩形加载波导的单膜尺寸范围，为光波导开关的设计与制作提供了参考数据。     

集成光学用单模磁光波导薄膜

采用双层（ＢｉＡｌ）ＹＩＧ膜结构来制作单模磁光波导。通过改变外延生长工艺来调节两层薄膜的折射率，可在一定波导的厚度范围内实现单模传输。Ｘ射线衍射测量表明薄膜质量良好，且易磁化方向平行膜面，最后利用棱镜耦合，观察了波导中的暗ｍ线。     

单纯形法在非线性光波导传播特性分析中的应用

简要介绍了优化理论中的单纯形方法,并且应用到求解介质非线性光波导的色散方程。文中计算了非线性光波导传输特性的2个实例,1）非对称3层平板波导,由线性衬底、克尔型芯区和线性包层（LNL）组成;2）对称3层平板波导,由克尔型包层、衬底及线性芯区组成（NLN）。数值结果表明,非线性光波导的色散方程很困难求解时,单纯形方法对于分析非线性光波导的传输特性简便而且有效。     

通用二维波导模式数值计算方法及其应用

给出了一种通用精确的二维光波导模式有限差分数值计算方法，在处理波导边界时采用了无穷边界（导数为零）或消逝边界（场为零）在波导内部两种介质的界面处采用了电磁场边界条件，这样可得到标准的本征方程，允许不同波导层采用不同的差分间距，但同一波导要求采用均匀剖分，该方法适用于任何形式的波导。作为应用，文章对金属包层多量子阱光波导的模式双折射特性做了理论分析。     

高速电光调制器波导测试系统滤光片的研制

为了实现对基于BaTiO3薄膜的高速电光调制器波导精确测试,研制出了一种深背景、高截止度的滤光片,用于提高测试系统信噪比,排除杂光干扰。该滤光片采用双离子束溅射的制备方法,以Nb和SiO2作为沉积材料,借助TFCalc和Macleod软件进行膜系设计和工艺反馈分析,通过正交矩阵法简化了辅助离子源工艺参数的优化过程,保证了采用优化后的工艺制备的薄膜具有更低的吸收,利用实时标定薄膜材料沉积速率等方法,解决了膜层厚度精确控制等问题。制备的滤光片通带中心波长为1 550.1 nm,通带宽度5.1 nm,光密度在-0.1~30 dB处的波长间隔为1.9 nm,满足了波导精确测试系统的使用要求。     

基于光子晶体多层膜的对称薄膜波导特性研究

研究了一种“光子晶体多层膜+波导层+光子晶体多层膜”对称薄膜波导特性,光子晶体多层膜的第一禁带频率范围为73 THz～99 THz。采用多层介质平板波导理论研究了频率在73 THz～99 THz间的电磁波在波导中的传输特性。结果表明波导传输的是TE0和TM0基模,对于高次模式,不能在波导中传输,另外,频率在73 THz～99 THz间的电磁波在波导层（中心层）的功率约束因子（Γ）在0.99～1之间,即此时电磁波几乎完全局限在波导层内传输,为了比较,处在光子带隙外的频率分别为40 THz和50 THz的电磁波在波导层内的功率约束因子（Γ）分别为0.84和0.86,因此,利用光子带隙特征,由光子晶体多层膜构造的对称薄膜波导具有超低损耗特性。     

理想匹配层及模式匹配法分析多段平面光波导结构

将理想匹配层（PML）吸收边界条件和模式匹配法用于多段平面光波导结构分析，给出了一种改进的平面光波导结构的PML吸收边界条件，并对光波导的光场分布进行数值模拟，所得结果表明了PML吸收边界条件应用于多段平面光波导结构分析的有效性。该方法也可用于分析复杂结构的平面光波导。     

硅 SIMOX 单模脊形光波导研制

本文描述硅光波导技术的重大突破：（１）用ＳＩＭＯＸ技术代替传统的硅外延型光波导，解决了衬底吸收光波．从而显著改善了光波导的传播损耗．（２）在理论及实验上均已解决用调整脊形的高宽比（高宽均能达１０微米左右），制取单模脊形光波导．这种光波导的下覆盖层是ＳｉＯ２，传播损耗小；断面积大，和单模光纤耦合良好．满足了光集成技术中对光波导的几项重要要求．     

一种高分辨率触觉指纹传感器

本文描述了一种基于光的全内反射（ＴＩＲ）原理，用光学玻璃作为波导极，在其上覆盖一层深色弹性膜的触觉指纹传感器。该传感器具有一般刚性波导板触觉传感器的高分辨率特点；耐用性好，成本低，能够清晰地获取人的手指纹理，非常适合用作自动指纹识别系统中的指纹读取仪。     

全硅集成光学—理论与工艺（Ⅶ）（续六）：第七讲 硅分支波导

全硅集成光学──理论与工艺（Ⅶ）（续六）第七讲硅分支波导赵策洲（副教授）（西安电子科技大学微电子所，西安７１００７１）１引言硅分支波导起到了光功率的传输和分割作用。它是硅耦合器和硅电光开关的重要组成部分。硅分支波导分支角的大小决定了它的功能和作用。尽...     

Low-Loss and Low-Birefringence High-Contrast Silicon-Oxynitride Waveguides for Optical Communication

Silicon-oxynitride waveguides fabricated by plasma-enhanced chemical vapor deposition are very attractive for passive optical components used in optical networks. We use a combination of an high-index contrast and compact core dimensions for the realization of small bending radii. To achieve the high quality requirements with the desired waveguide design the layer deposition and the waveguide fabrication are optimized. Furthermore, we discuss the interface of the high-index optical components to standard single-mode fiber (SSMF) and coupling tolerances, which is more difficult compared to common fiber-mode-matched wave guides. We show results of fabricated Mach-Zehnder interferometer-switches, tunable ring resonators and present a solution to reduce the waveguide birefringence by adjusting the mechanical stress of the cover layer.     

Monolithic Integration of a Waveguide Optical Isolator With a Distributed Feedback Laser Diode in the 1.5- μm Wavelength Range

We present first monolithic integration of a waveguide optical isolator with a distributed feedback laser diode (DFB LD) in the 1.5-mum wavelength range. The integrated devices are composed of 0.25-mm-long index-coupled DFB LDs and 0.75-mm-long semiconductor active waveguide optical isolators. The semiconductor active waveguide optical isolators are based on the nonreciprocal loss in the semiconductor optical amplifier (SOA) waveguides with ferromagnetic metals (Fe). The fabrication process consists of two steps of metal-organic vapor phase epitaxy to grow the DFB LD/SOA layer structures, one dry-etching process for the waveguide stripe formation, and three steps of electron-beam evaporation for the electrodes and ferromagnetic metals deposition. They showed single-mode emission at 1543.8nm and 4-dB optical isolation under a magnetic field of 0.1 T.     

波导层介质对二维光子晶体反射光谱的影响

构建了基底介质为SiO2、表面覆层介质为TiO2 的二维光子晶体,采用严格耦合波法分析了二维光子晶体的窄带光学传输特性。分析了二维光子晶体的晶格周期、波导层的折射率及厚度对其反射光谱的影响。分析结果表明:当光子晶体的晶格周期和波导层介质厚度为常数时,随着波导层介质折射率的增大,光子晶体的反射峰值波长红移,且波导层折射率与反射峰值波长呈线性关系。当光子晶体波导层介质折射率为常数时,波导层厚度增大或光子晶体晶格周期的增大都会引起光子晶体反射峰值波长增大,但这两个参数与反射峰值波长只是在一定的变化范围内为线性关系。此种结构的二维光子晶体覆层表面吸附分布不均匀的介质时,通过分析光子晶体的呈现光谱可获得其表面吸附介质的不均匀特性。     

Radiation Fields of Optical Stripline Waveguides

Dispersion characteristics and radiation fields of an optical stripline waveguide radiating into free space are calculated. The waveguides are fabricated as multiple layers of differing dielectric materials. A top layer is etched to form a "cap" with an effective waveguide in a layer below the cap. Confinement of the fields to the waveguide is obtained in the vertical direction by dielectric discontinuities, while lateral confinement occurs because of spatial interference of a continuum of plane waves. The radiation field of the fundamental mode in a plane perpendicular to the waveguide layers is characterized by the layer widths and index discontinuities. Beamwidths of the fundamental mode in the plane parallel to the dielectric layers are developed in terms of the waveguide parameters. Values of these parameters which yield the best optical confinement under the stripe can be obtained.     

Low-loss GaAs/AlGaAs optical waveguides on InP substrates

It is shown that the waveguide losses in lattice-mismatched GaAs-on-InP structures can be significantly reduced using an appropriate buffer layer. An AlGaAs buffer layer sequence was used for this purpose. A thin (400 nm) layer of Al_0.7Ga_0.3As, with an index below that of InP, was placed adjacent to the GaAs guiding layer both to maximize optical confinement in the guide and to increase the allowable guide dimensions for a single planar waveguide mode. Additional separation between guide and mismatched interface was achieved by inserting an Al_0.5Ga_0.5As layer with an index nearly equal to that of InP between the low-index buffer and InP. The final waveguide structure also included a thin (<40 nm) GaAs layer which was used to initiate growth and did not affect waveguide performance. Low losses (typically 3 dB/cm, with best results below 1 dB/cm) were achieved at a 1.52-μm wavelength for samples grown by organometallic chemical vapor deposition     

Thermooptic interferometric switches fabricated by electron beamirradiation of silica-on-silicon

The thermal stability of channel optical waveguide devices fabricated by electron beam irradiation of plasma-enhanced chemical vapor deposition (PECVD) silica-on-silicon is investigated. The degree of stability is dependent on the starting material and on the use of thermal annealing prior to irradiation. High-temperature postprocessing is shown to reduce modal confinement, increasing losses in waveguide bends and the coupling coefficient in directional couplers. A low-temperature cladding process based on a thick MgF₂ layer is described, and low-loss thermooptic Mach-Zehnder interferometric switches are demonstrated     

Semiconductor Waveguide Optical Isolators Towards Larger Optical Isolation Utilizing Nonreciprocal Phase Shift by Ferromagnetic Co

We theoretically investigated optical isolation in Co–InGaAsP semiconductor active waveguide optical isolators based on a nonreciprocal phase shift. By appropriate design of the waveguide layer structure and ferromagnetic metal, a large alpha parameter can be obtained, and the optical isolation was estimated to be larger than 30 dB in Mach–Zehnder interferometric waveguide optical isolators. The length of the nonreciprocal phase shifting region is as short as 1.3 mm.      

200K高特征温度的1.3μm AlInGaAs应变单量子阱激光器

在20～80℃范围内连续工作条件下,非对称波导层结构的1.3μm AlInGaAs/AlInAs单量子阱激光器的特征温度为200K,这是目前国内报道的相同有源材料、相同发射波长的激光器中最高的特征温度值.因此AlInGaAs是长波长光纤激光器的理想有源区材料.研究表明非对称波导结构能降低光吸收,提高激光器的高温特性和COD阈值.     

光纤尾纤波分复用滤光膜的研制

根据光纤通信无源器件对光学薄膜的特殊需求, 要求在光纤尾纤上镀制较复杂的波分复用滤光膜, 针对光纤镀膜所存在的难点问题, 利用TFCalc 膜系设计软件采用解析法设计出一个初始的规整膜系, 再结合梯度优化法在该规整膜系上有选择性的局部优化, 并考虑镀膜设备所允许的膜层灵敏度, 评估其鲁棒性和可镀制性, 从而设计出满足光谱特性要求的滤光膜膜系.然后通过对德国莱宝APS1104 型镀膜机进行内部结构改造并选择合适的冷镀工艺, 最终采用离子源辅助沉积对所设计的膜系进行了实际镀制, 获得了性能优良的光纤尾纤波分复用滤光膜.     

双面金属包覆单轴晶体波导的偏振转换研究

利用转移矩阵方法计算了双面金属包覆单轴晶体波导结构中的色散曲线、反射谱。结果表明,双面金属包覆结构使得波导可以被自由空间光场激发;单轴晶体的光轴取向能对该结构中的波导模式进行调控,使入射光波中的Ey、Ez分量发生相互转换耦合,从而在波导层中形成杂化模。通过调节耦合金属层厚度可以对出射光偏振状态的控制,实现TE线偏振入射光向TM线偏振反射光的转换以及线偏振入射光向圆偏振反射光的转换。