100-GHz cross-cascaded arrayed waveguide gratings (AWGs)-based wavelength selective optical switching optical cross-connects (OXCs) modules with Mach-Zehnder interferometer (MZI) thermo-optic (TO) variable optical attenuator (VOA) arrays and optical truetime- delay (TTD) line arrays is successfully designed and fabricated using polymer photonic lightwave circuit. Highly fluorinated photopolymer and grafting modified organic-inorganic hybrid material were synthesized as the waveguide core and cladding, respectively. The one-chip transmission loss is ~6 dB and the crosstalk is less than ~30 dB for the transverse-magnetic (TM) mode. The actual maximum modulation depths of different thermo-optic switches are similar, ~15.5 dB with 1.9 V bias. The maximum power consumption of a single switch is less than 10mW. The delay time basic increments are measured from 140 to 20 ps. Proposed novel module is flexible and scalable for the dense wavelength division multiplexing network.

由于特种光束的独特性质和丰富应用，光场调控技术近年来得到了越来越广泛的关注。设计特定结构调控普通高斯光束的振幅、相位或偏振方向，可以得到一系列特殊光场。利用一种偏振敏感的光取向材料，基于动态缩微投影曝光系统的液晶光控取向技术，可实现精确、任意和可重构的液晶方位角的取向控制。基于该项技术制备了二值或渐变的液晶微结构元件，对入射光场的各个参量维度进行调控，产生了高品质、高效率的涡旋光束、矢量光束和艾里光束。利用该项技术制备的器件具有成本低廉、轻便集成、电光可调、偏振可控和宽波段适用等特点。综述了本课题组近期在该领域的系列研究工作，或将为光场调控技术带来全新的可能，为液晶光学器件带来更广泛的应用。

利用溶胶 -凝胶法制备了有机 -无机杂化光敏性 SiO2-TiO2材料，在单晶硅基片上旋转涂膜，经前烘、紫外光固化、淋洗、后烘等步骤，在硅片上得到复制有掩模微图案的薄膜。用紫外 -可见光 -近红外分光光度计测试了薄膜的光透过吸收性质，用 Fourier红外光谱仪测试了不同紫外光辐照时间下薄膜的红外振动吸收光谱，用高倍光学显微镜和扫描电子显微镜 (SEM)观察制备得到的薄膜微图案。结果表明：薄膜在紫外可见光区域的光透过率约为 90%，紫外光照能促使不同的官能团间发生缩聚反应， 80℃前烘温度处理以及 15 min左右的紫外光辐照能够得到清晰、精确的薄膜微图案。

A new organic-inorganic hybrid material, which shows photo-induced reduction of refractive index as well as volume contraction, is prepared using a sol-gel method. This material is coated on a Si substrate by spin-coating to manufacture film. After irradiated by ultraviolet (UV) light with a deuterium lamp for 5 h, the thickness of film decreases largely by 55%, and the refractive index of film changes from 1.484 to 1.445 at 550 nm. The film’s optical thickness exhibits an exponential change with the increasing irradiation time. Futhermore, the photo-patternning of the organic-inorganic hybrid film without any further process (wet etching and thermal curing) is performed utilizing the volume contraction on UV-light irradiation. This film has potential applications for fabrication of patterned filter array and apodizing filter by direct light writing, and also demonstrates good temperature stability and immunity to visible light exposure.

Sn/Yb codoped silica optical fiber preform is prepared by the modified chemical vapor deposition (MCVD) followed by the solution-doping method. Ultraviolet (UV) optical absorption, photoluminescence (PL) spectra under 978-nm laser diode (LD) pumping, and refractive index change after exposure to 266-nm laser pulses are obtained. There is only a little change in the PL spectra while a positive refractive index change up to 2\times10^{-4} is observed after 30-min exposure to 266-nm laser pulses. The results show that both of the peculiar photosensitivity of Sn-doped silica and the gain property of Yb-doped silica fiber are preserved in the Sn/Yb codoped silica optical fiber preform. The experimental data suggest that the photosensitivity of the fiber preform under high energy density laser irradiation should be mainly due to the bond-breaking of oxygen deficient defects, while under relatively low energy density laser irradiation, the refractive index change probably originates from the photoconversion of optically active defects.

The synthesis of zinc oxide (ZnO) nanowires is achieved by vapor phase transportation (VPT) method. The designed quartz tube, whose both ends are narrow and the middle is wider, is used to control the growth of ZnO nanowires. Dielectrophoresis (DEP) method is employed to align and manipulate ZnO nanowires which are ultrasonic dispersed and suspended in ethanol solution. Under the dielectrophoretic force, the nanowires are trapped on the pre-patterned electrodes, and further aligned along the electric field and bridge the electrode gap. The dependence of the alignment yield on the applied voltage and frequency is investigated.