Guided Wave Optics in Super-EO Materials

本研究的总体目标是获得支持和促进高电光系数钨青铜铁电材料（“超级eo材料”）在各种导波光学器件中的应用的分析和实验结果。德克萨斯A&amp大学为制造钨青铜衬底的第一个低损耗波导和电光调制器而开发的技术将作为拟议项目的基础。这种波导是通过一个简单的过程产生的，在这个过程中，来自有图案的表面薄膜的静态应变产生了局部折射率的增加。罗克韦尔国际科学中心（Rockwell International Science Center）已经为Texas A&amp提供了好几年的超级eo材料，在拟议的项目过程中，该中心将继续担任这一合作角色。研究将在五个关键任务领域进行：(1)静态应变光学（SSO）波导建模，(2)器件设计，(3)材料表征，(4)调制器和开关开发，以及(5)可调谐滤波器研究。考虑到应变光学和电光对局部折射率变化的贡献，将计算SSO波导中TE和TM偏振的二维折射率分布。本文将采用变分法进行波导模态分析。将测量波导和器件模型所需的参数，如应变光学和电光系数、折射率和热膨胀系数。最近发现的“自极化”效应将被实验研究，以确定在高温下处理SSO器件后，在没有极化的情况下存在大的电光效应的条件。利用SSO波导的电光截止调制器、耦合波导开关和可调谐通道下降滤波器将在罗克韦尔衬底上设计、制造并表征。该研究将为在导波器件中使用超级eo材料奠定基础，并在未来十年中在宽带通信网络中得到越来越多的应用。将寻求调制器和开关，其性能比其在LiNbO3中的对应物（导波电光器件的传统衬底选择）表现出数量级的改进。将探索用于波长复用的新型通道下降滤波器，具有前所未有的调谐范围，低串扰和最小的电功率耗散。成功的演示将增强罗克韦尔对钨青铜基板商业化的兴趣，以便它们将普遍用于研究和设备应用。＊＊＊

9522740 Taylor The overall objective of this research is to obtain analytical and experimental results which support and promote the application of high-electrooptic-coefficient tungsten bronze ferroelectric materials ("super-EO materials") in a variety of guided wave optical devices. Techniques developed at Texas A&M for making the first low-loss waveguides and electrooptic modulators in tungsten bronze substrates will serve as the foundation for the proposed project. The waveguides are produced by a simple process in which static strain from a patterned surface film creates a localized refractive index increase. The Rockwell International Science Center, which has supplied super-EO materials to Texas A&M for several years, will continue in this collaborative role during the course of the proposed project. Research will be conducted in five critical task areas: (1) static strain optic (SSO) waveguide modeling, (2) device design, (3) material characterization, (4) modulator and switch development, and (5) tunable filter investigations. Two-dimensional refractive index profiles for TE and TM polarizations in SSO waveguides will be computed, considering both strain-optic and electrooptic contributions to the localized index change. A variation method will be utilized for waveguide mode analysis. Parameters needed for the waveguide and device models, such as strain-optic and electrooptic coefficients, refractive indices, and thermal expansion coefficients, will be measured. The recently discovered "self-poling" effect will be investigated experimentally to determine the conditions under which a large electrooptic effect is present without poling after processing of an SSO device at elevated temperatures. Electrooptic cutoff modulators, coupled waveguide switches, and tunable channel dropping filters which make use of the SSO waveguides will be designed, fabricated in the Rockwell substrates, and characterized. The proposed research will lay the groundwork for using super-EO materials in guided wave devices which could find increasing application in broadband communication networks over the next decade. Modulators and switches which exhibit order-of-magnitude improvement in performance over their counterparts in LiNbO3 - the traditional substrate of choice for guided wave electrooptic devices - will be sought. New channel-dropping filters for wavelength multiplexing with unprecedented tuning range, low crosstalk, and minimal electrical power dissipation will be explored. Successful demonstrations should reinforce Rockwell's expressed interest in commercializing the tungsten bronze substrates so that they will be generally available for research and device application. ***