MRI: Acquisition of Instrumentation for Optical Propagation Loss Measurement in Novel Waveguide Materials

用于信息处理和传输的集成光波导具有折射率略有不同的核心和包层结构。折射率对比引导光线在核心通过全内反射。开发材料合成和加工技术，将集成光学器件从复杂的气相沉积制造工艺中解放出来，具有相当大的动力。与传统的硅玻璃基和晶体波导材料相比，对新材料和新架构的需求也同样存在，这些新材料和新架构可以提供更高的带宽和更大的组成灵活性。我们的研究结果表明，聚合物、玻璃纳米复合材料和胶体溶胶-凝胶材料是非常有前途的波导材料，它们结合了成分的灵活性和快速、相对廉价的加工要求。最初的波导传播损耗研究表明，这些材料的损耗为2 dB/cm。正在进行的研究表明，溶胶-凝胶波导的热回流可能会将这种损失降低到1 dB/cm以下。对聚合物导板的持续研究表明，氟化支链电光染料可以掺入低损耗聚合物基质中，薄膜损耗远低于1 dB/cm。这两项研究都提供了令人信服的证据，证明这些材料是有前途的波导应用新材料。此外，我们提出了重要的结果，证明波导的设计，制造和表征是高等物理和化学本科生的一个极好的训练机会，并填补了学生为材料科学的高级学习做准备的关键需求。研究和学生培训的持续进展取决于获得精确定位和成像设备，以便准确测量光传播损耗。材料研究通过光纤和激光等创新改变了技术领域。例如，高效率的半导体激光器与低损耗光纤很好地匹配，导致了高速互联网传输等丰富的电信发展。为最终通过光纤传输而准备光信号的设备被称为集成光学设备。所有集成光学元件都有一个共同的材料结构，叫做波导，它将光信号限制在比人类头发厚度还小的明确区域内。对于简化波导结构制造的材料合成和加工技术有相当大的动力。与此同时，迫切需要让本科理科生更容易接触到波导材料的研究，以便为研究生研究和工业提供适当训练的学生。聚合物和胶体溶胶-凝胶材料是满足材料研究界技术和培训需求的几种有前途的方法。波导可以用简单的涂层技术从这些材料中制造出来，并且两者都提供了相当大的组成灵活性。任何新型波导材料的效用都取决于其以最小衰减传输光的能力，因此，评估吸收和散射引起的光损失是任何波导材料研究工作的重要组成部分。我们的初步结果强烈表明，聚合物和胶体溶胶-凝胶材料可以产生适合应用的光学损耗。研究和学生培训的持续进展取决于精确定位和成像设备的发展，以精确测量光传播损耗。

Integrated optical waveguides for information processing and transmission are characterized by core and cladding structures of slightly different refractive index. The refractive index contrast guides light rays within the core via total internal reflection. There is considerable motivation to develop materials synthesis and processing techniques that free integrated optics from complex vapor deposition fabrication processes. There is likewise demand for new materials and architectures that offer increased bandwidth and greater compositional flexibility than conventional silica-glass based and crystalline waveguide materials. We present results demonstrating that polymeric, glass nanocomposite, and colloidal sol-gel materials are highly promising waveguide materials that combine compositional flexibility with fast and relatively inexpensive processing requirements. Initial waveguide propagation loss investigations reveal these materials exhibit losses of order 2 dB/cm. Ongoing studies reveal that thermal reflowing of sol-gel waveguides is likely to reduce this loss below 1 dB/cm. Continuing investigation of polymeric guides has demonstrated that fluorinated branched electro-optic dyes can be incorporated in low loss polymer hosts with thin-film losses of well below 1 dB/cm. Both studies provide compelling evidence that these are promising new materials for waveguide applications. In addition, we present important results demonstrating that waveguide design, fabrication, and characterization is an excellent training opportunity for advanced physics and chemistry undergraduates, and fills a critical need in preparing students for advanced study in materials science. Continued progress on both research and student training is contingent on the acquisition of precision positioning and imaging equipment for the accurate measurement of optical propagation loss. Materials research has transformed the technological landscape through innovations such as optical fibers and lasers. For example, highly efficient semiconductor lasers are well-matched to low-loss optical fiber, resulting in a wealth of telecommunications developments such as high speed Internet transmission. The devices which prepare light signals for eventual transmission over fiber optic lines are referred to as integrated optics. All integrated optics have in common material structures called waveguides that confine light signals to well-defined regions smaller than the thickness of a human hair. There is considerable motivation for materials synthesis and processing techniques that simplify the fabrication of waveguide structures. At the same time, there is an urgent need to make the study of waveguide materials more accessible to undergraduate science students, in order to provide properly trained students for both graduate research and industry. Several promising approaches that satisfy both the technological and training needs of the materials research community are based on polymeric and colloidal sol-gel materials. Waveguides can be fabricated from these materials using simple coating techniques, and both offer considerable compositional flexibility. The utility of any novel waveguide material depends on its ability to transmit light with minimal attenuation, thus making the assessment of optical losses due to absorption and scattering an essential component of any waveguide materials research effort. Our preliminary results strongly suggest that polymeric and colloidal sol-gel materials can yield optical losses suitable for applications. Continued progress on both research and student training is contingent on the development of precision positioning and imaging equipment for the accurate measurement of optical propagation loss.