非线性导波光学与波导全光开关器件

综述了非线性导波光学的研究内容，着重介绍了基于三阶非线性的波导光开关器件的研究成果，其中包括频率调制型器件，振幅调制型器件及孤子非线性波导器件。此外，还讨论了非线性光波导材料的优化问题。     

一种新型的光波导阵列电光快速扫描器

研究一种新型的光波导阵列电光快速扫描器，分析了它的工作原理及光波导阵列结构对输出光空间分布特性的影响，并通过实验验证了器件的扫描特性，指出这种光波导阵列器件可以用很小的控制电压（＜10V），实现二维空间快速宽视场窄光束扫描。     

基于道格拉斯格式的宽角有限差分光束传播法分析大角度交叉波导

交叉波导是集成光学中的一种重要的器件单元，针对大角度交叉波导的结构及折射率分布，运用基于广义道格拉斯算子的宽角多步有限差分光束传播法模拟大角度交叉波导的传输特性，数值计算出波导中的光场的分布。与Crank-Nicholson格式的有限差分光束传播法相比，该算法在几乎不增加计算时间和计算机内存资源的情况下，结合了广义道格拉斯格式的有限差分光束传播法截断误差小[只有o(△x)^4]和宽角多步法所具有较高精度的优点，是光波导器件理想的数值模拟工具。在此基础上计算分析了大角度交叉波导的输出分支波导的能量与交叉角度的关系，以及交叉角度对波导间能量耦合的影响。这为实际的设计制作光器件的工作提供了极好的基础。     

基于大芯径晶体波导的半导体可饱和吸收镜锁模激光器

大芯径晶体波导可吸收更高功率的泵浦光，能够实现更高的输出功率，同时在锁模运行时芯层中的峰值功率密度相对较低，而且减少了非线性效应的积累。基于此，构建了一种基于Yb:YAG大芯径晶体方波导的被动锁模皮秒激光器。实验中，首先使用高反镜替代半导体可饱和吸收镜(SESAM),在较高的泵浦功率下调节晶体波导的位置和角度以实现泵浦光与波导芯层的匹配；然后，仔细调节球面反射镜的角度，使信号光耦合进波导芯层中以尽量减小腔内的损耗。所设计的激光器采用折叠腔结构，在腔内没有色散补偿器件的情况下，实现了平均功率为10.2 W、脉冲宽度为65 ps、重复频率为30.15 MHz、单脉冲能量为0.34μJ的激光输出。     

M-Z型极化DANS聚合物电光波导强度调制器研究

研究了Mach-Zehnder型极化聚合物电光波导强度调制器的制备工艺.器件采用DANS (4-dimethylamino-4′nitro-stlibene)聚合物为电光波导材料，由电光波导层、上下介质缓冲层、上下金属电极层构成五层波导结构.对五层光波导各层之间的光学、化学以及微加工工艺的相互兼容性进行了深入研究.采用紫外光漂白方法制备出侧壁光滑的条波导，采用钨丝电晕极化方法对DANS聚合物波导进行有效极化，使其具有电光特性.通过优化器件制备工艺，研制出工作波长为1300 nm的M-Z型电光波导强度调制器原型器件.实验测得器件半波电压约为10 V，调制带宽约为1 GHz.     

一阶模的滤除及在Y分支和多模干涉结构中的应用

Y分支和多模干涉结构广泛应用于平面光波导器件中，在这些器件中，Y分支和多模干涉结构输出对称性具有重要意义。引入Y分支和多模干涉结构输出的不对称主要原因是这两种结构中产生了一阶导模，设计一种新的耦合器结构，在这个结构中．两根单模波导分别放置在一根多模波导两边，并且单模波导的传播常量与多模波导的一阶模的传播常量相同，这种结构可以将一阶导模滤除。在Y分支和多模干涉结构中使用了这种结构，模拟结果表明，采用这种耦合器的Y分支和多模干涉结构具有非常好的输出对称性。     

单侧耦合16通道100GHz硅基二氧化硅阵列波导光栅的研制

介绍了一种新型单侧耦合16通道、100GHz通道间隔的硅基二氧化硅阵列波导光栅(AWG)。通过增加一个Y分支波导结构,将AWG的输入、输出波导等间距整齐排列,仅用一个光纤阵列(FA)就可以对AWG器件进行耦合封装。这种AWG的结构设计可有效地减小器件尺寸和增加波导结构的弯曲半径,可减少器件的抛光和耦合时间,可降低器件的成本。     

波导-同轴线的脊型转换器设计与测试

射频测量系统中经常会用到波导-同轴线转换器，主要是利用其将射频器件的波导端口转换成能够直接接入测量仪器的50 Ω同轴线。本文设计的648 MHz/WR1500波导同轴转换器主要用于CSNS升级工程（CSNS-II）超导直线射频器件的测量。利用切比雪夫脊型阶梯阻抗变换和探针耦合的方式实现波导到同轴线的转换。对脊加载波导和不连续同轴线分别进行了分析，得到最优尺寸。为了提高测量精度，设计的波导-同轴线转换器具有低插入损耗、低驻波比和宽带宽等特性。最后对生产的转换器进行了测试，测试结果与仿真结果相近，能够满足作为测量器件的使用要求。     

Ti∶LiNbO_3二维渐变折射率光波导传播常数的计算

从Ti∶LiNbO3波导截面折射率分布的特点出发，得出一套计算传播常数简单而精确的方法。文中对该法进行了分析，并应用该方法计算了钛扩散波导的色散关系。该方法为钛扩散光波导集成光学器件的设计提供了一种较可靠的理论手段。     

Ti：LiNbO3二维渐变折射率光波导传播常数的计算

从Ｔｉ：ＬｉＮｂＯ３波导截面折射率分布的特点出发，得出一套计算传播常数简单而精确的方法，文中对该法进行了分析，并应用该方法计算了钛扩散波导的色散关系，该方法为钛扩散光波导集成光学器件的设计提供了一种较可靠的理论手段。     

Polymeric 32-channel arrayed waveguide grating multiplexer using fluorinated poly (ether ether ketone)

In wavelength division multiplexing (WDM) systems, an arrayed waveguide grating (AWG) multiplexer is a key component. A polymeric AWG multiplexer has recently attracted much attention due to its low cost processing and a potential of integration with other devices. Fluorinated poly (ether ether ketone)(FPEEK) is excellent material for fabrication of optical waveguides due to its low absorption loss at 1.55-μm wavelength and high thermal stability. A 32-channel AWG multiplexer has been designed based on the grating diffraction theory and fabricated using newly synthesized FPEEK. During the fabrication process of the Polymer/Si AWG device, spin coating, vaporizing, photolithographic patterning and reactive ion etching (RIE) are used. The AWG multiplexer measurement system is based on a tunable semiconductor laser, infrared camera and a Peltier-type heater. The device exhibits a wavelength channel spacing of 0.8nm and a center wavelength of 1548 nm in the room temperature.     

Passive broadband silicon-on-insulator polarization splitter

We present the implementation of a novel wavelength independent polarization splitter on a silicon-on-insulator platform. The waveguide splitter is based on a zero-order arrayed waveguide grating (AWG) configuration. The splitting function is realized by employing cladding stress-induced birefringence. The device demonstrated a TE to TM splitting ratio better than -15 dB over a 20 nm tuning range centered around lambda=1550 nm and better than -10 dB over our entire accessible wavelength range from lambda=1465 nm to 1580 nm. The highest splitting extinction ratio achieved was -20 dB. To our knowledge, this is the first reported passive broadband polarization splitter based on AWG.     

低插入损耗阵列波导光栅的设计

研究了阵列波导光栅的插入损耗.针对损耗来源,讨论了各项损耗的研究方法.分析了结构参量对损耗的影响,讨论了降低损耗的设计思路.对结构参量进行优化,设计了8通道200 GHz间隔的阵列波导光栅,中心通道插入损耗为1.37 dB,低于目前商用器件的1/2.对阵列波导光栅的设计具有一定的指导意义.     

Design and fabrication of wavelength tunable AWGs based on the thermo-optic effect

In this Letter, a 16 channel 200 GHz wavelength tunable arrayed waveguide grating(AWG) is designed and fabricated based on the silicon on insulator platform. Considering that the performance of the AWG, such as central wavelength and crosstalk, is sensitive to the dimension variation of waveguides, the error analysis of the AWG with width fluctuations is worked out using the transfer function method. A heater is designed to realize the wavelength tunability of the AWG based on the thermo-optic effect of silicon. The measured results show that the insertion loss of the AWG is about 6 d B, and the crosstalk is 7.5 d B. The wavelength tunability of 1.1 nm is achieved at 276 m W power consumption, and more wavelength shifts will gain at larger power consumption.     

阵列波导光栅解调系统光电集成中Si纳米线AWG的设计

设计了一种阵列波导光栅解调集成系统中的8通道Si纳米线阵列波导光栅波分复用器。根据材料的折射率设计了单模波导截面尺寸,利用光束传播法对所设计阵列波导光栅进行了模拟。结果表明,器件尺寸为200μm×219μm,远小于目前技术较成熟的硅基SiO2的尺寸,光功率分布符合高斯分布,信道间隔为1.8nm,串扰小于-21dB。对小尺寸AWG的设计具有参考意义。     

AWG中波导间耦合造成的相位畸变的分析

用(1,1)阶Pad啨近似的广角BPM计算了阵列波导光栅(AWG)中由于阵列波导间耦合造成的相位畸变以及由于相位畸变引起的相位误差分别考虑了光从中心/非中心输入波导入射两种情况结果表明,波导间的耦合会造成显著的相位畸变,但由此引起的相位误差却很小,光从中心输入波导入射时对应的相位误差10-3rad,从非中心输入波导入射时的相位误差约为10-2rad针对波导阵列边缘效应引起的相位畸变,设计AWG结构时,在阵列部分两侧增加了边缘辅助波导结构,从而消除了边缘效应,使得边缘阵列波导对应的相位误差从10-1rad量级减小为10-3(10-2)rad量级.     

A novel wavelength dispersive device with a dispersive element based on staircase-like straight and parallel arrayed waveguides

We propose a new type of arrayed waveguide grating (AWG) multiplexer/demultiplexer based on modified group refractive index. This device is composed by an array of straight and parallel waveguides of equal length and each waveguide consist of two sections with different width. The length of the two sections are changed from a waveguide to the adjacent one following a linear dependence resulting in a wavelength dispersive waveguide array. An example of the device design for silicon-on-insulator (SOI) platform is provided and numerical simulations have been carried out for various arrayed waveguide parameters. We demonstrate that the group index modification can be used for tailoring device dispersion properties, and that it can also result in new dispersion characteristics predicted numerically not observed in conventional AWGs. Additional advantages are that the demultiplexer does not necessarily require bending waveguide sections as in a conventional AWG (de)multiplexers, and thus yields highly compact devices with potentially very low insertion loss. Channel spacing of 1 nm have been predicted for sub-micron waveguides sizes. In this paper it is also proposed a novel wavefront converter based on waveguide array lens-like element with waveguides broadened sections. Numerical results for different input/output geometries are analized.     

Wavelength-dispersive device based on a Fourier-transform Michelson-type arrayed waveguide grating

We propose a new type of arrayed waveguide grating (AWG) device that operates as a Fourier-transform (FT) spectrometer without the need of scanning elements. The large input aperture size typical of a FT spectrometer eliminates the requirement for a narrow single-mode input waveguide while still achieving high spectral resolution with a markedly increased light-gathering capability (etendue). An example of the device with a resolution of 0.07 nm (approximately 10 GHz) and designed for a silicon-on-insulator platform is presented. The calculated spectra show no noticeable deterioration for aperture widths as large as 40 microm, yielding more than a 50-fold increase in aperture size compared with conventional AWG or echelle grating based devices at the equivalent resolution.     

小尺寸低折射率差硅基二氧化硅阵列波导光栅

随着AWG型器件在光通信系统中的大规模应用,对低成本AWG芯片的需求越来越多。在各种降成本方案中,减小AWG芯片的尺寸是最有效的方法之一。本文介绍了一种新型小尺寸低折射率差硅基二氧化硅阵列波导光栅（AWG）的设计。在该AWG中,输入波导/输出波导与平板波导连接的部分制作成两侧为空气槽的高折射率差波导,所以在与输出平板波导连接处的相邻输出波导间距较小,这样可以在设计上缩短平板波导的长度、减少阵列波导的数量,实现较小的AWG芯片尺寸。该AWG的其它部分,如输入/输出波导与光纤耦合的部分、阵列波导光栅等均采用常规的低折射率波导工艺,所以就同时具有与常规的低折射率波导AWG相同的优点：如低耦合损耗、较好的串扰以及光学特性等。根据这个原理,设计了一种40通道100 GHz频率间隔的低折射率差硅基二氧化硅AWG,其芯片尺寸只有23.88 mm?10.5 mm,是传统相同材料制作的AWG尺寸的1/6。