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的特点是芯和包层结构的折射率略有不同。折射率对比度通过全内反射引导核心内的光线。人们有相当大的动力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过程中解放出来。与传统的硅基玻璃和晶体波导材料相比，对提供更高带宽和更大组成灵活性的新材料和结构的需求也同样存在。我们提出的结果表明，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光波导材料，它结合了组成的灵活性和快速和相对廉价的处理要求。初步的波导波传播损耗研究表明，这些材料的损耗约为2分贝/厘米。正在进行的研究表明，溶胶-凝胶波导的热回流很可能将这一损耗降低到1分贝/厘米以下。对聚合物导向器的持续研究表明，氟化支化电光染料可以掺入低损耗聚合物主体中，其薄膜损耗远低于1分贝/厘米。这两项研究都提供了令人信服的证据，表明这些材料是很有希望用于波导应用的新材料。此外，我们还介绍了重要的结果，证明了波导的设计、制造和表征是高等物理和化学本科生的一个极好的培训机会，并满足了学生为材料科学的高级学习做准备的关键需求。研究和学生培训方面的持续进展取决于能否获得准确测量光传播损耗的精确定位和成像设备。材料研究通过光纤和激光等创新改变了技术格局。例如，高效率的半导体激光器与低损耗光纤很好地匹配，导致了大量的电信发展，如高速互联网传输。为光纤线路上的最终传输准备光信号的设备被称为集成光学器件。所有集成光学器件都有共同的材料结构，称为波导，它将光信号限制在比人类头发厚度更小的明确区域。人们对简化波导结构制造的材料合成和加工技术有相当大的需求。与此同时，迫切需要使本科生能够更容易地学习波导材料，以便为研究生研究和工业提供适当培训的学生。满足材料研究界技术和培训需求的几种有希望的方法是基于聚合物和胶体溶胶-凝胶材料。使用简单的镀膜技术，就可以用这些材料制作波导，而且两者都提供了相当大的成分灵活性。任何一种新型波导材料的效用都取决于其在最小衰减的情况下传输光的能力，因此，由于吸收和散射造成的光学损失的评估成为任何波导材料研究工作的重要组成部分。我们的初步结果有力地表明，聚合物和胶体溶胶-凝胶材料可以产生适合于应用的光学损耗。在研究和学生培训方面的持续进展取决于为准确测量光传播损耗而开发的精确定位和成像设备。

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.