极化聚合物薄膜取向有序度及极化寿命的表征

研究了极化聚事物薄膜波导的退极化过程,提出了表征极化聚合物薄膜取向有序度和极化寿命的集成光学方法。采用集成光学中的棱镜耦合技术,测量极化前后聚合物薄膜光波导的各向异性有效折射率。通过求解各向异性介质光波导的模式本征方程,得到波导极化前后寻常光和非寻常光折射率的变化及其随时间衰减,进而得到取向有序度随时间的变化曲线。采用复合指数函数模型进行最小二乘曲线拟合,进而推测其极化寿命。实验中以键合型ＤＡＮＳ     

脊形聚合物光波导制备及理论分析

报道了利用铝膜作掩模,通过紫外光照射制备键合型聚合物DANS－PMMA脊形光波导的新方法。所制备的聚合物脊形光波导,其形状与通常的脊形波导相同,但内部折射率又与矩形波导类似。从理论上推导出脊形波导的模式本征值方程,并给出相应的归一化通用曲线,可以供相应波导设计和制备作为参考。     

As2S8玻璃条形波导的光激励法制备技术研究

为了在As2S8薄膜中制备条形波导,实验研究了As2S8薄膜光致折射率变化和密度变化的现象,采用棱镜耦合、X线衍射和远红外反射光谱等测试技术,确认了As2S8薄膜经紫外光辐照后薄膜密度增高、折射率增大的现象。采用可见光吸收谱测试技术,确认了经紫外光辐照的As2S8薄膜不发生黑化现象。在归纳了实验规律的基础上,提出并采用紫外光激励的方法试制了As2S8条形波导,采用自动调芯端面耦合的方法激励As2S8条形波导的导模,结果显示该波导具有良好的导波特性。     

集成光学 光波导材料与制备

TN2522006054304As2S8玻璃条形波导的光激励法制备技术研究=Study onAs2S8glass stripe waveguide fabrication using illumination[刊,中]/邹林儿(上海理工大学光电学院.上海(200093)),陈抱雪…//光学学报.—2006,26(7).—1043-1047为了在As2S8薄膜中制备条形波导,实验研究了As2S8薄膜光致折射率变化和密度变化的现象,采用棱镜耦合、X线衍射和远红外反射光谱等测试技术,确认了As2S8薄膜经紫外光辐照后薄膜密度增高、折射率增大的现象。采用可见光吸收谱测试技术,确认了经紫外光辐照的As2S8薄膜不发生黑化现象。在归纳了实验规律的基…     

新型杂萘联苯型聚芳醚砜硐聚合物光子材料成膜和光学特性

对新型聚合物光子材料杂萘联苯型聚芳醚砜硐(PPESK)波导薄膜的成膜工艺进行了系统的研究。分析了溶剂吸水性对成膜质量的影响,并通过氮气保护的方法获得了具有良好均一性的波导薄膜,其厚度一致性可优于1%,折射率一致性优于0.03%。采用棱镜耦合技术测量分析了PPESK波导薄膜的折射率、双折射、热光系数等光学特性,测量得到该材料在1310 nm波长处的损耗小于0.24 dB/cm,在1550 nm波长处的损耗小于0.52 dB/cm,表明该材料是一类性能良好的聚合物光子材料。     

聚合物自写入光波导的时域有限差分模拟

利用时域有限差分方法,对非线性光学聚合物SU-8环氧树脂在激光作用下,其折射率会升高的过程进行了数值模拟与分析,得到SU-8薄膜与激光作用一定时间之后,其内部折射率的分布。分别对表面是平面及表面带有微透镜的SU-8薄膜进行了模拟。结果表明,利用折射率升高引起的自聚焦效应,可以在SU-8薄膜内自写入波导;写入的波导以自聚焦焦点为分界点,分为锥形波导和柱形波导。写入的波导长度随着与激光作用时间的增加而增长;在与激光相同的作用时间里,表面带有微透镜的SU-8薄膜,与表面是平面的SU-8薄膜相比,锥形波导的旁瓣更收敛,写入的波导长度更长;在微透镜底面半径保持不变以及曝光时间一定时,微透镜冠高与底面半径比例为0.08时比比例为0.24时写入的波导长度要长12.2%,其中锥形波导部分要长19.2%。     

光波导技术同步测量棱镜及波导薄膜参数

依据全反射理论和棱镜耦合原理,实现了对棱镜折射率及波导薄膜材料折射率和厚度的同步测量。使用高准直半导体激光器激光入射到棱镜内部与波导膜的分界面上,逐步旋转棱镜或改变棱镜的入射角,得到棱镜耦合M线,曲线前面几组的波谷为波导模激发,在M线左侧收尾处有一个不完整波峰,其反射光强随入射角迅速衰减,为全反射时的临界点,由此可实现棱镜及波导薄膜参数的同步测量;用此法测量了棱镜耦合一体化平面波导棱镜的折射率和聚甲基丙烯酸甲酯(PMMA)聚合物波导薄膜的折射率和厚度。测量棱镜折射率精度为±1.9×10-4,波导薄膜折射率和厚度的精度分别为±6.2×10-4 μm和±1.6×10-2 μm。     

棱镜耦合法测量聚合物薄膜波导的参数

通过棱镜耦合方法测量了聚合物薄膜构成的三层平板介质波导不同阶导模下的有效折射率,通过计算机编程解光波导的色散方程,得出了介质薄膜的折射率和厚度.     

1感光溶胶-凝胶法制备光波导研究

采用溶胶-凝胶技术与化学修饰相结合的方法,制备了具有紫外感光特性的SiO2/Al2O3溶胶及其凝胶薄膜,并通过在溶胶中加入聚乙二醇使其形成有机-无机复合结构,经一次提拉制膜就可获得18 μm厚的感光性凝胶薄膜.利用薄膜自身的感光性,使紫外光通过掩模照射薄膜,再经过溶洗和200℃、1 h的热处理,就可获得厚度达到15 μm、线宽约为100 μm的波导阵列.对这种波导薄膜的折射率和的透射率进行了研究.     

侧链型聚合物DANS-PMMA脊形条波导的制备

有机聚合物的紫外漂白,经过一系列复杂的光化学反应,会使聚合物薄膜的折射率和厚度降低。在此基础上,利用金属掩模对聚合物薄膜进行选择性紫外漂白,制备出了聚合物脊形条波导。紫外漂白不需要对聚合物薄膜进行光刻和腐蚀便可获得边缘和表面比较整齐和光滑的脊形条波导,对减少波导的散射损耗十分有利。本文介绍了利用紫外漂白和金属掩模方法制备侧链型聚合物DANS（4－dimethylamino-4’nitro-stlibene)-PMMA(polymethyl methacrylate)脊形条波导的工艺过程,并对关键工艺进行了讨论。     

Reduction of insertion loss after annealing of silicon oxynitride optical waveguides

The insertion losses of silicon oxynitride (SiON) waveguides have been measured in the 1550 nm wavelength region. The waveguide structure consisted of a 2.0μm SiON waveguide core with a refractive index of 1.50, a 0.5μm SiO₂ upper cladding and a 5.0μm SiO₂ lower cladding with a refractive index of 1.45. It was found that the wavelength-dependent insertion losses of the waveguide were greatly reduced by annealing, and the loss was decreased more than 5.7 dB/cm at 1550 nm after annealing at optimum conditions. The former was attributed to the reduction of the absorption caused by N-H and Si-H vibration modes, and the latter was due to the improvement of the interface roughness and homogeneity in the waveguides after annealing.     

Dispersion characteristics of complex refractive-index planar slab optical waveguide by using finite element method

In this paper, finite element method (FEM) mode analyses of planar slab optical waveguide having complicated refractive index profile are presented. We try to estimate the dispersion graph, mode cut-off condition, group delay and waveguide dispersion for the case of α-power and chirped-type refractive index profile. In order to obtain the more accurate result, we have derived the higher-order polynomial, which establishes the suitable relationship between b and V for different profile of optical waveguide. On the basis of the derived polynomials, the waveguide dispersion is analyzed for different type of refractive index profile waveguide. Our study shows that the waveguide dispersion can be substantially reduced when we deployed the optical waveguide having linearly chirped-type refractive index profile. Earlier too, the arbitrary refractive index profile has been analyzed but to the best of our knowledge chirped-type refractive index profile has not been analyzed till date for the case of planar slab optical waveguide.     

Efficient coupling of a laser to a waveguide using a taper designed by conformal mapping

Maximising the optical power collected in a waveguide from the diffracting field of a semiconductor laser is desirable in optical fibre communication systems. However, the spot size and phase front curvature of the laser field usually makes a poor overlap with the mode of the receiving waveguide. Various proposals have been made to improve this coupling. This paper presents the design of a tapered waveguide section, having the correct geometry and refractive index profile, to efficiently capture and transform the rapidly diffracting light from a semiconductor laser to a planar wavefront in a straight waveguide. Experimentally, such an approach requires the refining of available techniques (UV exposure, ion implantation or diffusion) to obtain the required grading of the refractive index profile within the tapered input section of the receiving waveguide.     

Investigations of the E-O behavior in the poled polymer waveguide

The electro-optic (E-O) properties of the slab polymer waveguide induced by electric poling have been studied experimentally. The thin film waveguide was prepared by a synthesized polymer polypelargonamide and poled by applying voltage between the electrodes. I–V curves and E-O characteristics of the polymer films were in-situ measured during poling. In order to evaluate the molecular dipole orientation under the poling field, the absorption spectra of this film was observed by FTIR. The E-O performance of the polymer slab film was also estimated by the Mach–Zehnder interferometer.     

Dye-doped polymeric planar waveguide devices based on a thermal UV-bleaching technique

A new type of single-mode embedded dye-doped polymeric planar waveguide device based on cross-linkable negative photoresist has been successfully designed and fabricated using a UV-bleaching technique. A notable difference in the refractive index of the resist between exposed and un-exposed regions was observed, which was found to be dependent on the curing temperature. The new fabrication technique is a simple, rapid, and controllable process. The easy-to-fabricate waveguide structure is suitable for planar light-wave circuit applications. By optimizing the poling temperature and the dopant levels of Disperse Red 1, the material showed excellent photostability and exhibited a electro-optic coefficient, γ₃₃, of 25 pm/V. The dye-doped polymeric planar waveguide devices will be useful in realizing electro-optic (EO) modulators and switches.     

键合型DANS聚合物光波导电晕极化及其二阶非线性衰减

对键合型DANS聚合物薄膜光波导的电晕极化过程及其二阶非线性衰减特性进行了研究.采用本文给出的电晕极化参数,制成了具有较长极化寿命的极化聚合物薄膜光波导,为进一步研究其二阶非线性光学性质奠定了基础.     

一种新型的光纤锥形耦合器

提出了一种光纤波导折射率渐变的新型锥形（Taper）耦合器件，其原理是基于光纤中Ge缺陷在紫外光照射下而产生的光致折射率的变化。利用光纤在高压、低温下渗氢技术使单模光纤的光致折射率变化△n达6×10-3数量级；通过控制曝光条件就可以在光纤中产生一定规律的锥形结构，使单模光纤的模场半径由4．8μm缩小到3．2μm。由耦合波理论分析表明该器件具有较好的基模传输特性。     

掺半导体玻璃(SDG)波导非线性饱和的导波测量方法

掺半导体玻璃波导的折射率分布是通过多模波导有效折射率测量得到的.当耦合进入波导的激光功率密度变化时,可在不同模深度处,测量到波导的非线性折射率系数,并获得波导非线性折射率系数与功率密度的关系.从而得到波导的非线性饱和值为1.54×10-4.