聚合物复合薄膜DR13/PMMA的制备及其光学特性

薄膜的厚度、折射率和传输损耗等参数在电光系数的确定和光波导器件的设计和制作过程中都是重要的参考数据。采用旋涂法制备了三种不同质量比的偶氮化合物染料分散红13(DR13)与聚合物聚甲基丙烯酸甲酯(PMMA)复合薄膜;利用分光光度计测量样品的吸收光谱;利用棱镜耦合仪测量了薄膜的厚度和折射率,并对不同波长下的折射率进行拟合得到折射率色散曲线;采用视频摄像技术研究样品的光传输特性,利用自己编写的计算机程序来处理其实验结果。DR13/PMMA复合薄膜在300nm和500nm处有两个大的吸收峰,而在其他波段,尤其是在通信波段没有明显吸收。薄膜的膜厚大约为1~2μm,其折射率随着质量比的增加而增大,随着激光波长的增大而降低,膜厚和折射率的误差分别为3.2×10-1μm和1.5×10-3。三种质量比(10%,15%和20%)的薄膜传输损耗分别为1.5269dB/cm,2.7601dB/cm和3.6291dB/cm,可以看出随着DR13质量比的增大,光传输损耗也逐渐增大,即DR13的含量对于传输损耗的影响较大。     

40GHz铌酸锂电光调制器

本文遵循减小损耗的思路 ,提出了复合电极的结构,设计制做了这种电极结构的调制器并进行了分析.实验测得微波传输损耗系数α0＜0.3 dB/[cm(GHz)1 /2],在29～38 GHz内相对调制指数变化约3.5 dB.     

基于PVK/PbS纳米晶有机无机复合薄膜电双稳器件性能研究

通过简单旋涂方法,制备了一种基于硫化铅（PbS）纳米晶与聚乙烯基咔唑（PVK）的有机/无机复合薄膜电双稳器件,并对所制备的器件进行性能测试及其电荷传输机制研究。首先采用热注入的方法制备了尺寸均一的立方形PbS纳米晶,然后将PbS纳米晶与PVK聚合物混合作为活性层材料,制备了有机/无机复合薄膜电双稳器件。该器件展示了良好的电双稳特性并且可以实现稳定的“读-写-读-擦”操作。器件的最大电流开关比能够达到10⁴。并进一步对器件在正向电压下的I-V曲线进行了理论拟合,发现在不同电流传导状态下,器件符合不同的电传导模型。进而分析了该电双稳器件中的电荷传输机制,认为在电场的作用下,发生在纳米晶与聚合物之间的电场诱导电荷转移是产生电双稳特性的主要原因。     

湿法腐蚀制备的SOI光波导

用化学湿法腐蚀的方法制作了SOI光波导,并且用三维波束传播方法分析和设计了单模波导和1×2 3dB多模干涉分束器,修正了有效折射率和导模传输方法的误差.制作的器件具有低传输损耗(- 1 37dB/cm)、低附加损耗(- 2 2dB)、良好的均衡性(0 3dB)等优良性能.     

P-nc-si:H薄膜材料及在微晶硅薄膜太阳电池上应用

对RF PECVD技术沉积p nc Si:H薄膜材料进行了研究。随着功率的增大材料的晶化率增大。B的掺杂可以提高材料的电导率,同时会抑制材料的晶化,在纳米Si薄膜材料中B的掺杂效率很高,少量的B即可获得高的电导率,而对材料晶化影响不大。用比较高沉积功率和少量B的方法获得了高电导率、宽光学带隙和高晶化率的P型纳米Si薄膜材料(σ=0.7S/cm,Eopt>2.0eV)。将这种材料应用于微晶硅(μc Si)薄膜太阳能电池中,电池结构为:glass/SnO2/ZnO/p nc Si:H/I μC Si:H/n Si:H。首次获得效率η=4.2%的μC Si薄膜太阳能电池(Voc=0.399V,Jsc=20.56mA/cm2,FF=51.6%)。     

湿法腐蚀制备的SOI光波导

用化学湿法腐蚀的方法制作了SOI光波导,并且用三维波束传播方法分析和设计了单模波导和1×2 3dB多模干涉分束器,修正了有效折射率和导模传输方法的误差.制作的器件具有低传输损耗(-1.37dB/cm)、低附加损耗(-2.2dB)、良好的均衡性(0.3dB)等优良性能.     

硅衬底上PZT薄膜的制备及其特性分析

利用溶胶-凝胶提拉技术在低阻硅衬底上以钛酸铅(PT)作缓冲层,成功地制备了锆钛酸铅(PZT)高介电常数介质膜,其锆钛组分比为4 5∶5 5 .研究了薄膜结晶状态与制备条件的关系及相应的介电、铁电特性.结果表明,用这种方法制备的PZT薄膜在80 0℃退火1 5 m in晶化已相当完善,以(1 1 0 )为择优取向;这些样品的结晶尺度根据衍射峰的半高宽估计为1 4～2 5 nm左右;采用Sawyer- Tower电路和L CR电桥测试法获得的结果表明,经过80 0℃退火1 5 min的PZT样品,其剩余极化强度为4 7.7μC/ cm2 ,矫顽场强为1 8k V/ cm,介电常数为1 5 8,损耗因子为0 .0 4～0 .0 5 5     

聚合物脊形光波导设计

用5层非对称平面波导理论和等效折射率法(ERIM)分析了金属电极对聚合物脊形光波导横向模式特性及其传输损耗的影响。计算结果表明：在工作波长1．55μm波段,当常规脊形光波导的芯层厚度大于0．8μm、包层厚度大于3．0μm时,才能保证传输损耗的理论极限小于0．1dB／cm;当脊波导刻蚀深度为0.l一0．2μm、对应脊波导宽度为7—5μm时,可满足脊波导横向单模传输。     

掺杂LiYF_4:Er,Yb纳米晶的聚合物平面光波导放大器

采用高温热分解法合成了粒径约为10nm的LiYF4…Er,Yb纳米晶,将其掺杂入SU-8聚合物作为光波导放大器的有源层。以SiO2作为下包层,P(MMA-GMA)聚合物作为上包层,制备了LiYF4…Er,Yb纳米晶掺杂SU-8聚合物平面光波导放大器。当980nm波长抽运光功率为180mW时,在1535nm波长处获得了2.3dB/cm的相对增益率。     

聚合物单模光波导的研究

采用一种间接方法，计算出了DCNP／PEK－c主客掺杂聚合物薄膜在1300nm波长下的折射率；在对其平板光波导研究的基础上，进行了新型单模倒脊型聚合物光波导的设计与制做。结果表明，此种新型光波导具有较好的单模性。     

Loss Measurements on Polymer Thin Film Optical Waveguides

Asimple setup for the measurement of transmission loss in polymer thin film optical waveguides is described.A new electro-optic polymer film has been prepared.The transmission loss of the film is measured before and after corona poling.And the loss is determined to be 1.84 dB/cm and 2.14dB/cm, respectively.     

Low-loss electrooptic BaTiO/sub 3/ thin film waveguide modulator

A strip-loaded electrooptic waveguide modulator based on an epitaxial BaTiO/sub 3/ thin film was fabricated and characterized for the first time. The strip-loaded waveguide structure greatly improves waveguide propagation and polarization-dependent loss performance. A propagation loss of 1.1 dB/cm and polarization dependent loss of 0.1 dB/cm were measured. The electrooptic waveguide modulator exhibited a half-wave voltage-interaction length product of 4.5 V /spl middot/ cm at a wavelength of 1542 nm. The measured effective electrooptic coefficient of the as-grown BaTiO/sub 3/ waveguide modulator was 38 pm/V. The experimental results indicate that a strip-loaded thin film waveguide modulator is suitable for photonic applications.     

Scattering loss reduction in polymer waveguides by reflowing

A polymer channel waveguide was fabricated by reactive ion etching. Loss measurements were performed on this waveguide before and after reflowing. The waveguide loss decreases from 3 to 1 dB/cm by heating the sample slightly above the glass transition temperature of the core material. This result in channel loss is very close to the measured film losses of 0.8 dB/cm.     

纳米微晶／聚合物复合材料介电性的表征

在全面考虑纳米（ｎｍ）微晶与聚合物所形成的复合材料的极化机构情况下,对纳米微晶和聚合 物分别采用Ｄｅｂｙｅ和ＮＨ函数弛豫理论,用Ｏｎｓａｇｅｒ有铲场理论详细计算了该类复合材料的复介电常数的频率响应。制备了纳米复合材料薄膜ＰＴ／ＰＥＫ－Ｃ。由以上理论结果模拟出的纳米复合的介电性和测量结果有较好的一致性。     

Polymeric variable optical attenuator based on long range surface plasmon polaritons

Proposed is a polymeric variable optical attenuator based on long range surface plasmon polaritons (LRSPPs) along a thin metal stripe embedded in polymers. The device is operated by controlling radiation loss of the LRSPP mode resulting from the temperature gradient of the polymer cladding caused by a heater. For guiding LRSPPs and efficient coupling of singlemode fibres, gold stripes 20 nm thick, 4 /spl mu/m wide and 1 cm long are utilised. To obtain a long physical lifetime, the heater is formed on the top of the polymer cladding with a 200 nm Au film which is about ten times thicker than the thin metal waveguide. The fabricated device is characterised at a wavelength of 1.55 /spl mu/m, exhibiting high attenuation of less than 30 dB with an operating power of 100 mW. A fibre-to-fibre total insertion loss of 6.1 dB is achieved when using singlemode fibres.     

Polymer-Based Long-Range Surface Plasmon Polariton Waveguides for 10-Gbps Optical Signal Transmission Applications

We present characteristics of very thin Au strip waveguides based on long-range surface plasmon polaritons (LR-SPPs) along thin Au strips embedded in polymers. We also report a 10 Gbps optical signal transmission via LR-SPPs with the pig-tailed Au strip waveguide at a telecommunication wavelength of 1.55 mum. We limited the thickness, width, and length up to ~20 nm, ~ 10 mum, and ~5 cm, respectively, for practical applications. At 1.55 mum, loss properties of the Au strip waveguides were theoretically and experimentally evaluated with thickness, width and cladding material. The lowest propagation loss of ~1.4 dB/cm was experimentally obtained with the 14-nm-thick and 2-mum-wide Au strip. With a single-mode fiber, the lowest coupling loss of less than 0.1 dB/facet was achieved with the 14-nm-thick and 7.5-mum-wide Au strip. The lowest insertion loss was obtained 7.7 dB with the 14-nm-thick, 5-mum-wide, and 1.5-cm-long Au strip. The propagation loss was improved approximately 30% for the 17-nm-thick Au strip with lowering the refractive index of the cladding polymer by 0.01. In the 10 Gbps optical signal transmission experiment, the LR-SPP waveguide exhibits an excellent eye opening and a 2.2 dB power penalty at 10^-12 bit error rate. These all results indicate that the LR-SPP waveguide is a potential transmission line for optical interconnects to overcome inherent problems in electric interconnects.     

Influence of water sorption on acrylic polymer waveguide loss

The influence of water sorption on acrylic polymer waveguides was studied by measuring the loss changes in the atmosphere at 13 to 98% RH. The absorption peak at 1.41 μm increased from 0.5 to 2 dB/cm due to water sorption. This peak resulted in a small loss change of 0.03 dB/cm at 1.3 μm, which was successfully measured using a 57 cm waveguide with a loss of around 0.1 dB/cm. Relationships between loss change and water sorption were also revealed by measuring the water content of the polymers     

Optical transmission losses in polycrystalline silicon strip waveguides: Effects of waveguide dimensions, thermal treatment, hydrogen passivation, and wavelength

Signal propagation delays dominate over gate delays in the ever-shrinking ultra large scale integrated (ULSI) circuits. Consequently, silicon-based monolithic optoelectronic circuits (SMOE) with their light speed signal propagation can provide unique advantages for future generations of microprocessors. For such SMOE circuits, we need optical interconnects compatible with silicon technology. Strip waveguides consisting of polycrystalline silicon (polySi) clad with SiO₂ offer excellent optical confinement and ease of fabrication that are ideal for such interconnect applications. One major challenge with using this material system, however, is its insertion loss. In this paper we provide techniques for minimizing optical transmission losses in polySi strip waveguides. Our previous work using polySi strip waveguides, showed an optical transmission loss of 15 dB/cm at λ=1.55 μm, which is a communication wavelength of choice in optical fibers because it represents an absorption minimum. Similar measurements in crystalline silicon strip waveguides¹ yielded transmission losses of less than 1 dB/cm. Hitherto, in decreasing loss from 77 dB/cm to 15 dB/cm, we had minimized loss from surface scattering by improving the film surface morphology, and decreased bulk absorption with hydrogen passivation. In this paper we report a further reduction in the residual bulk loss from 15 dB/cm to 9 dB/cm. By experimenting with different waveguide core dimensions, we find that the contribution of bulk loss towards net transmission loss decreases with waveguide core thickness. Additionally, high temperature treatment provides strain relief in the polySi, decreasing transmission loss. Annealing in an oxygen ambient is not recommended because it always increases transmission loss. Hydrogen passivation improves transmission, attributable to passivation of light-absorbing dangling bond defect sites present at polySi grain boundaries. Together, these methods have resulted in the lowest measured loss value of 9 dB/cm at λ=1.55 μm. Since integrated SiGe and Ge photodetectors are more efficient at shorter wavelengths like λ=1.32 μm, transmission loss is also measured at λ=1.32 μm. Losses at the two wavelengths (1.32 μm and 1.55 μm) are similar when defects and stress in the waveguides are minimized.